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Best podcasts about sirnas

Latest podcast episodes about sirnas

Empowered Patient Podcast
Using AI Big Data to Engineer More Efficient Drugs to Treat Rare and Common Diseases with Chris Hart Creyon Bio

Empowered Patient Podcast

Play Episode Listen Later Oct 15, 2024 20:51


Chris Hart, Co-Founder, CEO, and President of Creyon Bio, is focused on engineering drugs rather than just discovering them through serendipity and traditional methods.  Creyon is developing oligonucleotide medicines for rare and common diseases by applying AI and big data models of the molecular and genetic basis of diseases to develop safe and effective drugs more quickly.  Chris elaborates, "When we think about drug engineering versus drug discovery, we're thinking about how we take this process that currently requires us to do trial-and-error identification of molecules that may be beneficial in the clinic to a place where we can say, can I build the right machinery, the right data, the right models, the right processes to go in and understand if I want to make this modulation within a cell, here's the molecule that will do it and I can have confidence that it will be safe." "In terms of drug engineering and the type of drug engineering that Creyon does, what made starting Creyon the right thing to do and why it's the right time and the right time to do it is that the computing power does exist to crunch large numbers and do the analysis we need to do to build the right models. But what didn't exist for us, and I don't think it exists broadly in the industry, is the right data. So a major focus of what Creyon has been doing for the last four years has been on how we create the right data in an efficient way such that we can engineer drugs to have the properties we need them to have as drugs, which is to say safe and effective and not just bioactive." "Our focus is oligonucleotide medicines, which generally are antisense oligos, siRNAs, and aptamers. This is a super-modality we often think about. What characterizes them is their polymeric nucleic acids that are chemically synthesized, and that's our primary focus. The indications we're going after are the upside of the medicines we make: they don't constrain themselves naturally to a therapeutic area. We can think broadly about whether or not it's an immunological disease or a neurological disease. We can use these medicines for any type of disease, and we can use them across the board regardless of whether it's a rare or a common disease." #CreyonBio #AIinHealthcare #BiotechInnovation #DrugDiscovery #DrugDevelopment #DrugEngineering #PersonalizedMedicine #PrecisionMedicine #RareDiseases creyonbio.com Download the transcript here

Empowered Patient Podcast
Using AI Big Data to Engineer More Efficient Drugs to Treat Rare and Common Diseases with Chris Hart Creyon Bio TRANSCRIPT

Empowered Patient Podcast

Play Episode Listen Later Oct 15, 2024


Chris Hart, Co-Founder, CEO, and President of Creyon Bio, is focused on engineering drugs rather than just discovering them through serendipity and traditional methods.  Creyon is developing oligonucleotide medicines for rare and common diseases by applying AI and big data models of the molecular and genetic basis of diseases to develop safe and effective drugs more quickly.  Chris elaborates, "When we think about drug engineering versus drug discovery, we're thinking about how we take this process that currently requires us to do trial-and-error identification of molecules that may be beneficial in the clinic to a place where we can say, can I build the right machinery, the right data, the right models, the right processes to go in and understand if I want to make this modulation within a cell, here's the molecule that will do it and I can have confidence that it will be safe." "In terms of drug engineering and the type of drug engineering that Creyon does, what made starting Creyon the right thing to do and why it's the right time and the right time to do it is that the computing power does exist to crunch large numbers and do the analysis we need to do to build the right models. But what didn't exist for us, and I don't think it exists broadly in the industry, is the right data. So a major focus of what Creyon has been doing for the last four years has been on how we create the right data in an efficient way such that we can engineer drugs to have the properties we need them to have as drugs, which is to say safe and effective and not just bioactive." "Our focus is oligonucleotide medicines, which generally are antisense oligos, siRNAs, and aptamers. This is a super-modality we often think about. What characterizes them is their polymeric nucleic acids that are chemically synthesized, and that's our primary focus. The indications we're going after are the upside of the medicines we make: they don't constrain themselves naturally to a therapeutic area. We can think broadly about whether or not it's an immunological disease or a neurological disease. We can use these medicines for any type of disease, and we can use them across the board regardless of whether it's a rare or a common disease." #CreyonBio #AIinHealthcare #BiotechInnovation #DrugDiscovery #DrugDevelopment #DrugEngineering #PersonalizedMedicine #PrecisionMedicine #RareDiseases creyonbio.com Listen to the podcast here

Ground Truths
Pradeep Natarajan: Preventing Heart Disease

Ground Truths

Play Episode Listen Later Aug 13, 2024 57:44


Pradeep is a brilliant geneticist and Director of Preventive Cardiology, holds the Paul & Phyllis Fireman Endowed Chair in Vascular Medicine at Mass General Hospital and on faculty at Harvard Medical School and the Broad Institute. His prolific research has been illuminating for the field of improving our approach to reduce the risk of heart disease. That's especially important because heart disease is the global (and US) #1 killer and is on the increase. We didn't get into lifestyle factors here since there was so much ground to cover on new tests. drugs, and strategies.A video snippet of our conversation on ApoB. Full videos of all Ground Truths podcasts can be seen on YouTube here. The audios are also available on Apple and Spotify.Transcript with links to key publications and audioEric Topol (00:06):Well, welcome to Ground Truths. I'm Eric Topol and with me is Pradeep Natarajan from Harvard. He's Director of Preventative Cardiology at the Mass General Brigham Health System and he has been lighting it up on the field of cardiovascular. We're going to get to lots of different parts of that story and so, Pradeep welcome.Pradeep Natarajan (00:31):Thanks Eric, really delighted and honored to be with you and have this discussion.Eric Topol (00:36):Well, for years I've been admiring your work and it's just accelerating and so there's so many things to get to. I thought maybe what we'd start off with is you recently wrote a New England Journal piece about two trials, two different drugs that could change the landscape of cardiovascular prevention in the future. I mean, that's one of the themes we're going to get to today is all these different markers and drugs that will change cardiology as we know it now. So maybe you could just give us a skinny on that New England Journal piece.Two New Lipid Targets With RNA DrugsPradeep Natarajan (01:16):Yeah, yeah, so these two agents, the trials were published at the same time. These phase two clinical trials for plozasiran, which is an siRNA against APOC3 and zodasiran, which is an siRNA against ANGPTL3. The reason why we have medicines against those targets are based on human genetics observations, that individuals with loss of function mutations and either of those genes have reduced lipids. For APOC3, it's reduced triglycerides for ANGPTL3 reduced LDL cholesterol and reduced triglycerides and also individuals that have those loss of function mutations also have lower risk for coronary artery disease. Now that's a very similar parallel to PCSK9. We have successful medicines that treat that target because people have found that carriers of loss of function mutations in PCSK9 lead to lower LDL cholesterol and lower coronary artery disease.(02:11):Now that suggests that therapeutic manipulation without significant side effects from the agents themselves for APOC3 and ANGPTL3 would be anticipated to also lower coronary artery disease risk potentially in complementary pathways to PCSK9. The interesting thing with those observations is that they all came from rare loss of function mutations that are enriched in populations of individuals. However, at least for PCSK9, has been demonstrated to have efficacy in large groups of individuals across different communities. So the theme of that piece was really just the need to study diverse populations because those insights are not always predictable about which communities are going to have those loss of function mutations and when you find them, they often have profound insights across much larger groups of individuals.Eric Topol (03:02):Well, there's a lot there that we can unpack a bit of it. One of them is the use of small interfering RNAs (siRNA) as drugs. We saw in the field of PCSK9, as you mentioned. First there were monoclonal antibodies directed against this target and then more recently, there's inclisiran which isn't an RNA play if you will, where you only have to take it twice a year and supposedly it's less expensive and I'm still having trouble in my practice getting patients covered on their insurance even though it's cheaper and much more convenient. But nonetheless, now we're seeing these RNA drugs and maybe you could comment about that part and then also the surprise that perhaps is unexplained is the glucose elevation.Pradeep Natarajan (03:53):Yeah, so for medicines and targets that have been discovered through human genetics, those I think are attractive for genetic-based therapies and longer interval dosing for the therapies, which is what siRNAs allow you to do because the individuals that have these perturbations, basically the naturally occurring loss of function mutations, they have these lifelong, so basically have had a one-time therapy and have lived, and so far, at least for these targets, have not had untoward side effects or untoward phenotypic consequences and only reduce lipids and reduce coronary artery disease. And so, instead of taking a pill daily, if we have conviction that that long amount of suppression may be beneficial, then longer interval dosing and not worrying about the pill burden is very attractive specifically for those specific therapeutics. And as you know, people continue to innovate on further prolonging as it relates to PCSK9.(04:57):Separately, some folks are also developing pills because many people do feel that there's still a market and comfort for daily pills. Now interestingly for the siRNA for zodasiran at the highest dose, actually for both of them at the highest doses, but particularly for zodasiran, there was an increase in insulin resistance parameters actually as it relates to hyperglycemia and less so as it relates to insulin resistance, that is not predicted based on the human genetics. Individuals with loss of function mutations do not have increased risks in hyperglycemia or type 2 diabetes, so that isolates it related to that specific platform or that specific technology. Now inclisiran, as you'd mentioned, Eric is out there. That's an siRNA against PCSK9 that's made by a different manufacturer. So far, the clinical trials have not shown hyperglycemia or type 2 diabetes as it relates inclisiran, so it may be related to the specific siRNAs that are used for those targets. That does merit further consideration. Now, the doses that the manufacturers do plan to use in the phase three clinical trials are at lower doses where there was not an increase in hyperglycemia, but that does merit further investigation to really understand why that's the case. Is that an expected generalized effect for siRNAs? Is it related to siRNAs for this specific target or is it just related to the platform used for these two agents which are made by the same manufacturer?Eric Topol (06:27):Right, and I think the fact that it's a mystery is intriguing at the least, and it may not come up at the doses that are used in the trials, but the fact that it did crop up at high doses is unexpected. Now that is part of a much bigger story is that up until now our armamentarium has been statins and ezetimibe to treat lipids, but it's rapidly expanding Lp(a), which for decades as a cardiologist we had nothing to offer. There may even be drugs to be able to lower people who are at high risk with high Lp(a). Maybe you could discuss that.What About Lp(a)?Pradeep Natarajan (07:13):Yeah, I mean, Eric, as you know, Lp(a) has been described as a cardiovascular disease risk factors for quite so many years and there are assays to detect lipoprotein(a) elevation and have been in widespread clinical practice increasing widespread clinical practice, but we don't yet have approved therapies. However, there is an abundance of literature preclinical data that suggests that it likely is a causal factor, meaning that if you lower lipoprotein(a) when elevated, you would reduce the risk related to lipoprotein(a). And a lot of this comes from similar human genetic studies. The major challenge of just relating a biomarker to an outcome is there are many different reasons why a biomarker might be elevated, and so if you detect a signal that correlates a biomarker, a concentration to a clinical outcome, it could be related to that biomarker, but it could be to the other reasons that the biomarker is elevated and sometimes it relates to the outcome itself.(08:10):Now human genetics is very attractive because if you find alleles that strongly relate to that exposure, you can test those alleles themselves with the clinical outcome. Now the allele assignment is established at birth. No other factor is going to change that assignment after conception, and so that provides a robust, strong causal test for that potential exposure in clinical outcome. Now, lipoprotein(a) is unique in that it is highly heritable and so there are lots of different alleles that relate to lipoprotein(a) and so in a well powered analysis can actually test the lipoprotein(a) SNPs with the clinical outcomes and similar to how there is a biomarker association with incident myocardial infarction and incident stroke, the SNPs related to lipoprotein(a) show the same. That is among the evidence that strongly supports that this might be causal. Now, fast forward to many years later, we have at least three phase three randomized clinical trials testing agents that have been shown to be very potent at lowering lipoprotein(a) that in the coming years we will know if that hypothesis is true. Importantly, we will have to understand what are the potential side effects of these medicines. There are antisense oligonucleotides and siRNAs that are primarily in investigation. Again, this is an example where there's a strong genetic observation, and so these genetic based longer interval dosing therapies may be attractive, but side effects will be a key thing as well too. Those things hard to anticipate really can anticipate based on the human genetics for off target effects, for example.(09:52):It's clearly a risk signal and hopefully in the near future we're going to have specific therapies.Eric Topol (09:57):Yeah, you did a great job of explaining Mendelian randomization and the fact the power of genetics, which we're going to get into deeper shortly, but the other point is that do you expect now that there's these multiple drugs that lower Lp(a) efficiently, would that be enough to get approval or will it have to be trials to demonstrate improved cardiovascular outcomes?Pradeep Natarajan (10:24):There is a great regulatory path at FDA for approval just for LDL cholesterol lowering and inclisiran is on the market and the phase three outcomes data has not yet been reported because there is a wide appreciation that LDL cholesterol lowering is a pretty good surrogate for cardiovascular disease risk lowering. The label will be restricted to LDL cholesterol lowering and then if demonstrated to have clinical outcomes, the label could be expanded. For other biomarkers including lipoprotein(a), even though we have strong conviction that it is likely a causal factor there hasn't met the bar yet to get approval just based on lipoprotein(a) lowering, and so we would need to see the outcomes effects and then we would also need to understand side effects. There is a body of literature of side effects for other therapies that have targeted using antisense oligonucleotides. We talked about potential side effects from some siRNA platforms and sometimes those effects could overtake potential benefits, so that really needs to be assessed and there is a literature and other examples.(11:31):The other thing I do want to note related to lipoprotein(a) is that the human genetics are modeled based on lifelong perturbations, really hard to understand what the effects are, how great of an effect there might be in different contexts, particularly when introduced in middle age. There's a lot of discussion about how high lipoprotein(a) should be to deliver these therapies because the conventional teaching is that one in five individuals has high lipoprotein(a), and that's basically greater than 75 nanomoles per liter. However, some studies some human genetic studies to say if you want to get an effect that is similar to the LDL cholesterol lowering medicines on the market, you need to start with actually higher lipoprotein(a) because you need larger amounts of lipoprotein(a) lowering. Those are studies and approaches that haven't been well validated. We don't know if that's a valid approach because that's modeling based on this sort of lifelong effect. So I'm very curious to see what the overall effect will be because to get approval, I think you need to demonstrate safety and efficacy, but most importantly, these manufacturers and we as clinicians are trying to find viable therapies in the market that it won't be hard for us to get approval because hopefully the clinical trial will have said this is the context where it works. It works really well and it works really well on top of the existing therapies, so there are multiple hurdles to actually getting it directly to our patients.How Low Do You Go with LDL Cholesterol?Eric Topol (13:02):Yeah, no question about that. I'm glad you've emphasized that. Just as you've emphasized the incredible lessons from the genetics of people that have helped guide this renaissance to better drugs to prevent cardiovascular disease. LDL, which is perhaps the most impressive surrogate in medicine, a lab test that you already touched on, one of the biggest questions is how low do you go? That is Eugene Braunwald, who we all know and love. They're in Boston. The last time I got together with him, he was getting his LDL down to close to zero with various tactics that might be extreme. But before we leave these markers, you're running preventive cardiology at man's greatest hospital. Could you tell us what is your recipe for how aggressive do you go with LDL?Pradeep Natarajan (14:04):Yeah, so when I talk to patients where we're newly getting lipid lowering therapies on, especially because many people don't have a readout of abnormal LDL cholesterol when we're prescribing these medicines, it's just giving them a sense of what we think an optimal LDL cholesterol might be. And a lot of this is based on just empirical observations. So one, the average LDL cholesterol in the modern human is about 100 to 110 mg/dL. However, if you look at contemporary hunter gatherers and non-human primates, their average LDL is about 40 to 50 and newborn babies have an LDL cholesterol of about 30. And the reason why people keep making LDL cholesterol lowering medicines because as you stack on therapies, cardiovascular disease events continue to reduce including down to these very low LDL cholesterol values. So the population mean for LDL cholesterol is high and everybody likely has hypercholesterolemia, and that's because over the last 10,000 years how we live our lives is so dramatically different and there has not been substantial evolution over that time to change many of these features related to metabolism.(15:16):And so, to achieve those really low LDL cholesterol values in today's society is almost impossible without pharmacotherapies. You could say, okay, maybe everybody should be on pharmacotherapies, and I think if you did that, you probably would reduce a lot of events. You'll also be treating a lot of individuals who likely would not get events. Cardiovascular disease is the leading killer, but there are many things that people suffer from and most of the times it still is not cardiovascular disease. So our practice is still rooted in better identifying the individuals who are at risk for cardiovascular disease. And so, far we target our therapies primarily in those who have already developed cardiovascular disease. Maybe we'll talk about better identifying those at risk, but for those individuals it makes lots of sense to get it as low as possible. And the field has continued to move to lower targets.(16:07):One, because we've all recognized, at least based on these empirical observations that lower is better. But now increasingly we have a lot of therapies to actually get there, and my hope is that with more and more options and the market forces that influence that the cost perspective will make sense as we continue to develop more. As an aside, related aside is if you look at the last cholesterol guidelines, this is 2018 in the US this is the first time PCSK9 inhibitors were introduced in the guidelines and all throughout that there was discussions of cost. There are a lot of concerns from the field that PCSK9 inhibitors would bankrupt the system because so many people were on statins. And you look at the prior one that was in 2013 and cost was mentioned once it's just the cost effectiveness of statins. So I think the field has that overall concern.(17:01):However, over time we've gotten comfortable with lower targets, there are more medicines and I think some of this competition hopefully will drive down some of the costs, but also the overall appreciation of the science related to LDL. So long-winded way of saying this is kind of the things that we discussed just to give reassurance that we can go to low LDL cholesterol values and that it's safe and then we think also very effective. Nobody knows what the lower limit is, whether zero is appropriate or not. We know that glucose can get too low. We know that blood pressure can be too low. We don't know yet that limit for LDL cholesterol. I mean increasingly with these trials we'll see it going down really low and then we'll better appreciate and understand, so we'll see 40 is probably the right range.Eric Topol (17:49):40, you said? Yeah, okay, I'll buy that. Of course, the other thing that we do know is that if you push to the highest dose statins to get there, you might in some people start to see the hyperglycemia issue, which is still not fully understood and whether that is, I mean it's not desirable, but whether or not it is an issue, I guess it's still out there dangling. Now the other thing that since we're on LDL, we covered Lp(a), PCSK9, the siRNA, is ApoB. Do you measure ApoB in all your patients? Should that be the norm?Measuring ApoBPradeep Natarajan (18:32):Yeah, so ApoB is another blood test. In the standard lipid panel, you get four things. What's measured is cholesterol and triglycerides, they're the lipids insoluble in blood to get to the different tissues that get packaged in lipoprotein molecules which will have the cholesterol, triglycerides and some other lipids and proteins. And so, they all have different names as you know, right? Low density lipoprotein, high density lipoprotein and some others. But also in the lipid panel you get the HDL cholesterol, the amount of cholesterol in an HDL particle, and then most labs will calculate LDL cholesterol and LDL cholesterol has a nice relationship with cardiovascular disease. You lower it with statins and others. Lower risk for cardiovascular disease, turns out a unifying feature of all of these atherogenic lipoproteins, all these lipoproteins that are measured and unmeasured that relate to cardiovascular disease, including lipoprotein(a), they all have an additional protein called ApoB. And ApoB, at least as it relates to LDL is a pretty good surrogate of the number of LDL particles.(19:37):Turns out that that is a bit better at the population level at predicting cardiovascular disease beyond LDL cholesterol itself. And where it can be particularly helpful is that there are some patients out there that have an unexpected ratio between ApoB and LDL. In general, the ratio between LDL cholesterol and ApoB is about 1.1 and most people will have that rough ratio. I verify that that is the expected, and then if that is the expected, then really there is no role to follow ApoB. However, primarily the patients that have features related to insulin resistance have obesity. They may often have adequate looking LDL cholesterols, but their ApoB is higher. They have more circulating LDL particles relative to the total amount of LDL cholesterol, so smaller particles themselves. However, the total number of particles may actually be too high for them.(20:34):And so, even if the LDL cholesterol is at target, if the ApoB is higher, then you need to reduce. So usually the times that I just kind of verify that I'm at appropriate target is I check the LDL cholesterol, if that looks good, verify with the ApoB because of this ratio, the ApoB target should be about 10% lower. So if we're aiming for about 40, that's like 36, so relatively similar, and if it's there, I'm good. If it's not and it's higher, then obviously increase the LDL cholesterol lowering medicines because lower the ApoB and then follow the ApoB with the lipids going forward. The European Society of Cardiology has more emphasis on measuring ApoB, that is not as strong in the US guidelines, but there are many folks in the field, preventive cardiologists and others that are advocating for the increasing use of ApoB because I think there are many folks that are not getting to the appropriate targets because we are not measuring ApoB.Why Aren't We Measuring and Treating Inflammation?Eric Topol (21:37):Yeah, I think you reviewed it so well. The problem here is it could be part of the standard lipid panel, it would make this easy, but what you've done is a prudent way of selecting out people who it becomes more important to measure and moderate subsequently. Now this gets us to the fact that we're lipid centric and we don't pay homage to inflammation. So I wrote a recent Substack on the big miss on inflammation, and here you get into things like the monoclonal antibody to interleukin-6, the trial that CANTOS that showed significant reduction in cardiovascular events and fatal cancers by the way. And then you get into these colchicine trials two pretty good size randomized trials, and here the entry was coronary disease with a high C-reactive protein. Now somehow or other we abandon measuring CRP or other inflammatory markers, and both of us have had patients who have low LDLs but have heart attacks or significant coronary disease. So why don't we embrace inflammation? Why don't we measure it? Why don't we have better markers? Why is this just sitting there where we could do so much better? Even agents that are basically cost pennies like colchicine at low doses, not having to use a proprietary version could be helpful. What are your thoughts about us upgrading our prevention with inflammation markers?Pradeep Natarajan (23:22):Yeah, I mean, Eric, there is an urgent need to address these other pathways. I say urgent need because heart disease has the dubious distinction of being the leading killer in the US and then over the last 20 years, the leading killer in the world as it takes over non-communicable diseases. And really since the early 1900s, there has been a focus on developing pharmacotherapies and approaches to address the traditional modifiable cardiovascular disease risk factors. That has done tremendous good, but still the curves are largely flattening out. But in the US and in many parts of the world, the deaths attributable to cardiovascular disease are starting to tick up, and that means there are many additional pathways, many of them that we have well recognized including inflammation. More recently, Lp(a) that are likely important for cardiovascular disease, for inflammation, as you have highlighted, has been validated in randomized controlled trials.(24:18):Really the key trial that has been more most specific is one on Canakinumab in the CANTOS trial IL-1β monoclonal antibody secondary prevention, so cardiovascular disease plus high C-reactive protein, about a 15% reduction in cardiovascular disease and also improvement in cancer related outcomes. Major issues, a couple of issues. One was increased risk for severe infections, and the other one is almost pragmatic or practical is that that medicine was on the market at a very high price point for rare autoinflammatory conditions. It still is. And so, to have for a broader indication like cardiovascular disease prevention would not make sense at that price point. And the manufacturer tried to go to the FDA and focus on the group that only had C-reactive protein lowering, but that's obviously like a backwards endpoint. How would you know that before you release the medicine? So that never made it to a broader indication.(25:14):However, that stuck a flag in the broader validation of that specific pathway in cardiovascular disease. That pathway has direct relevance to C-reactive protein. C-reactive protein is kind of a readout of that pathway that starts from the NLRP3 inflammasome, which then activates IL-1β and IL-6. C-reactive protein we think is just a non causal readout, but is a reliable test of many of these features and that's debatable. There may be other things like measuring IL-6, for example. So given that there is actually substantial ongoing drug development in that pathway, there are a handful of companies with NLRP3 inflammasome inhibitors, but small molecules that you can take as pills. There is a monoclonal antibody against IL-6 that's in development ziltivekimab that's directed at patients with chronic kidney disease who have lots of cardiovascular disease events despite addressing modifiable risk factors where inflammatory markers are through the roof.(26:16):But then you would also highlighted one anti-inflammatory that's out there that's pennies on the dollar, that's colchicine. Colchicine is believed to influence cardiovascular disease by inhibiting NLRP3, I say believed to. It does a lot of things. It is an old medicine, but empirically has been shown in at least two randomized controlled trials patients with coronary artery disease, actually they didn't measure C-reactive protein in the inclusion for these, but in those populations we did reduce major adverse cardiovascular disease events. The one thing that does give me pause with colchicine is that there is this odd signal for increased non-cardiovascular death. Nobody understands if that's real, if that's a fluke. The FDA just approved last year low dose colchicine, colchicine at 0.5 milligrams for secondary prevention given the overwhelming efficacy. Hasn't yet made it into prevention guidelines, but I think that's one part that does give me a little bit pause. I do really think about it particularly for patients who have had recurrent events. The people who market the medicine and do research do remind us that C-reactive protein was not required in the inclusion, but nobody has done that secondary assessment to see if measuring C-reactive protein would be helpful in identifying the beneficial patients. But I think there still could be more work done on better identifying who would benefit from colchicine because it's an available and cheap medicine. But I'm excited that there is a lot of development in this inflammation area.Eric Topol (27:48):Yeah, well, the development sounds great. It's probably some years away. Do you use colchicine in your practice?Pradeep Natarajan (27:56):I do. Again, for those folks who have had recurrent events, even though C-reactive protein isn't there, it does make me feel like I'm treating inflammation. If C-reactive protein is elevated and then I use it for those patients, if it's not elevated, it's a much harder sell from my standpoint, from the patient standpoint. At the lower dose for colchicine, people generally are okay as far as side effects. The manufacturer has it at 0.5 milligrams, which is technically not pennies on the dollar. That's not generic. The 0.6 milligrams is generic and they claim that there is less side effects at the 0.5 milligrams. So technically 0.6 milligrams is off label. So it is what it is.CHIP and Defining High Risk People for CV DiseaseEric Topol (28:40):It's a lot more practical, that's for sure. Now, before I leave that, I just want to mention when I reviewed the IL-1β trial, you mentioned the CANTOS trial and also the colchicine data. The numbers of absolute increases for infection with the antibody or the cancers with the colchicine are really small. So I mean the benefit was overriding, but I certainly agree with your concern that there's some things we don't understand there that need to be probed more. Now, one of the other themes, well before one other marker that before we get to polygenic risk scores, which is center stage here, defining high risk people. We've talked a lot about the conventional things and some of the newer ways, but you've been one of the leaders of study of clonal hematopoiesis of indeterminate potential known as CHIP. CHIP, not the chips set in your computer, but CHIP. And basically this is stem cell mutations that increase in people as we age and become exceptionally common with different mutations that account in these clones. So maybe you can tell us about CHIP and what I don't understand is that it has tremendous correlation association with cardiovascular outcomes adverse as well as other system outcomes, and we don't measure it and we could measure it. So please take us through what the hell is wrong there.Pradeep Natarajan (30:14):Yeah, I mean this is really exciting. I mean I'm a little bit biased, but this is observations that have been made only really over the last decade, but accelerating research. And this has been enabled by advances in genomic technologies. So about 10 years or plus ago, really getting into the early days of population-based next generation sequencing, primarily whole exome sequencing. And most of the DNA that we collect to do these population-based analyses come from the blood, red blood cells are anucleate, so they're coming from white blood cells. And so, at that time, primarily interrogating what is the germline genetic basis for coronary artery disease and early onset myocardial infarction. At the same time, colleagues at the Broad Institute were noticing that there are many additional features that you can get from the blood-based DNA that was being processed by the whole exome data. And there were actually three different groups that converged on that all in Boston that converged on the same observation that many well-established cancer causing mutations.(31:19):So mutations that are observed in cancers that have been described to drive the cancers themselves were being observed in these large population-based data sets that we were all generating to understand the relationship between loss of function mutations in cardiovascular disease. That's basically the intention of those data sets for being generated for other things. Strong correlation with age, but it was very common among individuals greater than 70; 10% of them would have these mutations and is very common because blood cancer is extremely, it's still pretty rare in the population. So to say 10% of people had cancer causing driver mutations but didn't have cancer, was much higher than anyone would've otherwise expected. In 2014, there were basically three main papers that described that, and they also observed that there is a greater risk of death. You'd say, okay, this is a precancerous lesion, so they're probably dying of cancer.(32:17):But as I said, the absolute incidence rate for blood cancer is really low and there's a relative increase for about tenfold, but pretty small as it relates to what could be related to death. And in one of the studies we did some exploratory analysis that suggested maybe it's actually the most common cause of death and that was cardiovascular disease. And so, a few years later we published a study that really in depth really looked at a bunch of different data sets that were ascertained to really understand the relationship between these mutations, these cancer causing mutations in cardiovascular disease, so observed it in enrichment and older individuals that had these mutations, CHIP mutations, younger individuals who had early onset MI as well too, and then also look prospectively and showed that it related to incident coronary artery disease. Now the major challenge for this kind of analysis as it relates to the germline genetic analysis is prevalence changes over time.(33:15):There are many things that could influence the presence of clonal hematopoiesis. Age is a key enriching factor and age is the best predictor for cardiovascular disease. So really important. So then we modeled it in mice. It was actually a parallel effort at Boston University (BU) that was doing the same thing really based on the 2014 studies. And so, at the same time we also observed when you modeled this in mice, you basically perturb introduce loss of function mutations in the bone marrow for these mice to recapitulate these driver mutations and those mice also have a greater burden of atherosclerosis. And Eric, you highlighted inflammation because basically the phenotype of these cells are hyper inflamed cells. Interestingly, C-reactive protein is only modestly elevated. So C-reactive protein is not fully capturing this, but many of the cytokines IL-1β, IL-6, they're all upregulated in mice and in humans when measured as well.(34:11):Now there've been a few key studies that have been really exciting about using anti-inflammatories in this pathway to address CHIP associated cardiovascular disease. So one that effort that I said in BU because they saw these cytokines increased, we already know that these cytokines have relationship with atherosclerosis. So they gave an NLRP3 inflammasome inhibitor to the mice and they showed that the mice with or without CHIP had a reduction in atherosclerosis, but there was a substantial delta among the mice that are modeled as having CHIP. Now, the investigators in CANTOS, the manufacturers, they actually went back and they survey where they had DNA in the CANTOS trial. They measured CHIP and particularly TET2 CHIP, which is the one that has the strongest signal for atherosclerosis. As I said, overall about 15% reduction in the primary outcome in CANTOS. Among the individuals who had TET2 CHIP, it was a 64% reduction in event.(35:08):I mean you don't see those in atherosclerosis related trials. Now this has the caveat of it being secondary post hoc exploratory, the two levels of evidence. And so, then we took a Mendelian randomization approach. Serendipitously, just so happens there is a coding mutation in the IL-6 receptor, a missense mutation that in 2012 was described that if you had this mutation, about 40% of people have it, you have a 5%, but statistically significant reduction in coronary artery disease. So we very simply said, if the pathway of this NLRP3 inflammasome, which includes IL-6, if you have decreased signaling in that pathway, might you have an even greater benefit from having that mutation if you had CHIP versus those who didn't have CHIP. So we looked in the UK Biobank, those who didn't have CHIP 5% reduction, who had that IL-6 receptor mutation, and then those who did have CHIP, if they had that mutation, it was about a 60% reduction in cardiovascular disease.(36:12):Again, three different lines of evidence that really show that this pathway has relevance in the general population, but the people who actually might benefit the most are those with CHIP. And I think as we get more and more data sets, we find that not all of the CHIP mutations are the same as it relates to cardiovascular disease risk. It does hone in on these key subsets like TET2 and JAK2, but this is pretty cool as a preventive cardiologist, new potential modifiable risk factor, but now it's almost like an oncologic paradigm that is being applied to coronary artery disease where we have specific driver mutations and then we're tailoring our therapies to those specific biological drivers for coronary artery disease. Hopefully, I did that justice. There's a lot there.Why Don't We Measure CHIP?Eric Topol (36:57):Well, actually, it's phenomenal how you've explained that, but I do want to review for our listeners or readers that prior to this point in our conversation, we were talking about germline mutations, the ones you're born with. With CHIP, we're talking about acquired somatic mutations, and these are our blood stem cells. And what is befuddling to me is that with all the data that you and others, you especially have been publishing and how easy it would be to measure this. I mean, we've seen that you can get it from sequencing no less other means. Why we don't measure this? I mean, why are we turning a blind eye to CHIP? I just don't get it. And we keep calling it of indeterminate potential, not indeterminate. It's definite potential.Pradeep Natarajan (37:51):Yeah, no, I think these are just overly cautious terms from the scientists. Lots of people have CHIP, a lot of people don't have clinical outcomes. And so, I think from the lens of a practicing hematologists that provide some reassurance on the spectrum for acquired mutation all the way over to leukemia, that is where it comes from. I don't love the acronym as well because every subfield in biomedicine has its own CHIP, so there's obviously lots of confusion there. CH or clinical hematopoiesis is often what I go, but I think continuing to be specific on these mutations. Now the question is why measure? Why aren't we measuring it? So there are some clinical assays out there. Now when patients get evaluated for cytopenias [low cell counts], there are next generation sequencing tests that look for these mutations in the process for evaluation. Now, technically by definition, CHIP means the presence of these driver mutations that have expanded because it's detectable by these assays, not a one-off cell because it can only be detected if it's in a number of cells.(38:55):So there has been some expansion, but there are no CBC abnormalities. Now, if there's a CBC abnormality and you see a CHIP mutation that's technically considered CCUS or clonal cytopenia of unknown significance, sometimes what is detected is myelodysplastic syndrome. In those scenarios still there is a cardiovascular disease signal, and so many of our patients who are seen in the cancer center who are being evaluated for these CBC abnormalities will be detected to have these mutations. They will have undergone some risk stratification to see what the malignancy potential is. Still pretty low for many of those individuals. And so, the major driver of health outcomes for this finding may be cardiovascular. So those patients then get referred to our program. Dana-Farber also has a similar program, and then my colleague Peter Libby at the Brigham often sees those patients as well. Now for prospective screening, so far, an insurance basically is who's going to pay for it.(39:51):So an insurance provider is not deemed that appropriate yet. You do need the prospective clinical trials because the medicines that we're talking about may have side effects as well too. And what is the yield? What is the diagnostic yield? Will there actually be a large effect estimate? But there has been more and more innovation, at least on the assay and the cost part of the assay because these initial studies, we've been using whole exome sequencing, which is continuing to come down, but is not a widely routine clinical test yet. And also because as you highlighted, these are acquired mutations. A single test is not necessarily one and done. This may be something that does require surveillance for particular high risk individuals. And we've described some risk factors for the prevalence of CHIP. So surveillance may be required, but because there are about 10 genes that are primarily implicated in CHIP, that can substantially decrease the cost of it. The cost for DNA extraction is going down, and so there are research tests that are kind of in the $10 to $20 range right now for CHIP. And if flipped over to the clinical side will also be reasonably low cost. And so, for the paradigm for clinical implementation, that cost part is necessary.Eric Topol (41:10):I don't know the $10 or $20 ones. Are there any I could order on patients that I'm worried about?Pradeep Natarajan (41:17):Not yet clinical. However, there is a company that makes the reagents for at least the cores that are developing this. They are commercializing that test so that many other cores, research cores can develop it. I think it's in short order that clinical labs will adopt it as well too.Eric Topol (41:36):That's great.Pradeep Natarajan (41:37):I will keep you apprised.What About Polygenic Risk Scores?Eric Topol (41:39):I think that's really good news because like I said, we're so darn lipid centric and we have to start to respect the body of data, the knowledge that you and others have built about CHIP. Now speaking of another one that drives me nuts is polygenic risk score (PRS) for about a decade, I've been saying we have coronary disease for most people is a polygenic trait. It's not just a familial hypercholesterolemia. And we progressively have gotten better and better of the hundreds of single variants that collectively without a parental history will be and independently predict who is at double, triple or whatever risk of getting heart disease, whereby you could then guide your statins at higher aggressive or pick a statin, use one or even go beyond that as we've been talking about. But we don't use that in practice, which is just incredible because it's can be done cheap.(42:45):You can get it through whether it's 23andMe or now many other entities. We have an app, MyGeneRank where we can process that Scripss does for free. And only recently, Mass General was the first to implement that in your patient population, and I'm sure you were a driver of that. What is the reluctance about using this as an orthogonal, if you will, separate way to assess a person's risk for heart disease? And we know validated very solidly about being aggressive about lipid lowering when you know this person's in the highest 5% polygenic risk score. Are we just deadheads in this field or what?Pradeep Natarajan (43:30):Yeah, I mean Eric, as you know, lots of inertia in medicine, but this one I think has a potential to make a large impact. Like CHIP mutations, I said news is about 10% in individuals greater than 70. The prospect here is to identify the risk much earlier in life because I think there is a very good argument that we're undertreating high risk individuals early on because we don't know how to identify them. As you highlighted, Dr. Braunwald about LDL cholesterol. The other part of that paradigm is LDL cholesterol lowering and the duration. And as we said, everybody would benefit from really low LDL cholesterol, but again, you might overtreat that if you just give that to everybody. But if you can better identify the folks very early in life, there is a low cost, low risk therapy, at least related to statins that you could have a profound benefit from the ones who have a greater conviction will have future risk for cardiovascular disease.(44:21):You highlighted the family history, and the family history has given the field of clues that genetics play a role. But as the genome-wide association studies have gotten larger, the polygenic risk scores have gotten better. We know that family history is imperfect. There are many reasons why a family member who is at risk may or may not have developed cardiovascular disease. A polygenic risk score will give a single number that will estimate the contribution of genetics to cardiovascular disease. And the thing that is really fascinating to me, which is I think some of a clinical implementation challenge is that the alleles for an individual are fixed. The genotyping is very cheap. That continues to be extremely cheap to do this test. But the weights and the interpretation of what the effects should be for each of the SNPs are continually being refined over time.(45:18):And so, given the exact same SNPs in the population, the ability to better predict cardiovascular diseases getting better. And so, you have things that get reported in the literature, but literally three years later that gets outdated and those hypotheses need to be reassessed. Today, I'll say we have a great relative to other things, but we have a great polygenic risk score was just reported last year that if you compare it to familial hypercholesterolemia, which has a diagnostic yield of about 1 in 300 individuals, but readily detectable by severe hypercholesterolemia that has about threefold risk for cardiovascular disease. By polygenic risk score, you can find 1 in 5 individuals with that same risk. Obviously you go higher than that, it'll be even higher risk related to that. And that is noble information very early in life. And most people develop risk factors later in life. It is happening earlier, but generally not in the 30s, 40s where there's an opportunity to make a substantial impact on the curve related to cardiovascular disease.(46:25):But there is a lot of momentum there. Lots of interest from NIH and others. The major challenge is though the US healthcare system is really not well set up to prevention, as you know, we practice healthcare after patient's developed disease and prevent the complications related to progression. The stakeholder incentives beyond the patient themselves are less well aligned. We've talked a lot here today about payers, but we don't have a single payer healthcare system. And patients at different times of their lives will have different insurers. They'll start early in life with their parents, their first employer, they'll move on to the next job and then ultimately Medicare. There's no entity beyond yourself that really cares about your longevity basically from the beginning and your overall wellness. That tension has been a major challenge in just driving the incentives and the push towards polygenic risk scores. But there are some innovative approaches like MassMutual Life Insurance actually did a pilot on polygenic risk scoring.(47:33):They're in the business of better understanding longevity. They get that this is important data. Major challenges, there are federal protections against non-discrimination in the workplace, health insurance, not necessarily life insurance. So I think that there are lots of things that have to be worked out. Everybody recognizes that this is important, but we really have to have all the incentives aligned for this to happen at a system-wide level in the US. So there's actually lots of investment in countries that have more nationalized healthcare systems, lots of development in clinical trials in the UK, for example. So it's possible that we in the US will not be the lead in that kind of evidence generation, but maybe we'll get there.The GLP-1 DrugsEric Topol (48:16):Yeah, it's frustrating though, Pradeep, because this has been incubating for some time and now we have multi ancestry, polygenic risk scores, particularly for heart disease and we're not using it, and it's not in my view, in the patient's best interest just because of these obstacles that you're mentioning, particularly here in the US. Well, the other thing I want to just get at with you today is the drugs that we were using for diabetes now blossoming for lots of other indications, particularly the glucagon-like peptide 1 (GLP-1) drugs. This has come onto the scene in recent years, not just obviously for obesity, but it's anti-inflammatory effects as we're learning, mediated not just through the brain but also T cells and having extraordinary impact in heart disease for people with obesity and also with those who have heart failure, about half of heart failure for preserved ejection fraction. So recently you and your colleagues recently published a paper with this signal of optic neuropathy. It was almost seven eightfold increase in a population. First, I wanted to get your sense about GLP-1. We're also going to get into the SGLT2 for a moment as well, but how do you use GLP-1? What's your prognosis for this drug class going forward?Pradeep Natarajan (49:55):As it relates to the paper, I can't claim credit as one of my former students who is now Mass Eye and Ear resident who participated, but we can talk about that. There's obviously some challenges for mining real world data, but this was related to anecdotes that they were observing at Mass Eye and Ear and then studied and observed an enrichment. In general though, I feel like every week I'm reading a new clinical trial about a new clinical outcome benefit as it relates to GLP-1 receptor agonists. This is kind of one thing that stands out that could be interrogated in these other clinical trials. So I would have that caveat before being cautious about ocular complications. But the data has been overwhelmingly beneficial, I think, because at minimum, obesity and inflammation are relayed to myriad of consequences, and I'm really excited that we have therapies that can address obesity that are safe.(50:52):There's a legacy of unsafe medicines for obesity, especially related to cardiovascular disease. So the fact that we have medicines that are safe and effective for lowering weight that also have real strong effects on clinical outcomes is tremendous. We in cardiology are increasingly using a range of diabetes medicines, including GLP-1 receptor agonists and SGLT2 inhibitors. I think that is also the secular changes of what influences cardiovascular disease over time. I talked about over the last 10 years or so with this increase in deaths attributable to cardiovascular disease. If you look at the influences of traditional clinical risk factors today, many of them have decreased in importance because when abnormal, we recognize them, in general we modify them when recognized. And so, many of the things that are unaddressed, especially the features related to insulin resistance, obesity, they start rising in importance. And so, there is a dramatic potential for these kinds of therapies in reducing the residual risks that we see related to cardiovascular disease. So I'm enthusiastic and excited. I think a lot more biology that needs to be understood of how much of this is being influenced specifically through this pathway versus a very effective weight loss medicine. But also interesting to see the insights on how the effect centrally on appetite suppression has profound influences on weight loss as well too. And hopefully that will lead to more innovations in weight management.The SGLT-2 DrugsEric Topol (52:25):And likewise, perhaps not getting near as much play, but when it came on the cardiovascular scene that an anti-diabetic drug SGLT2 was improving survival, that was big, and we still don't know why. I mean, there's some ideas that it might be a senolytic drug unknowingly, but this has become a big part of practice of cardiology in patients with diabetes or with preserved ejection fraction heart failure. Is that a fair summary for that drug?Pradeep Natarajan (53:00):Yeah, I totally agree. I mean, as there has been increased recognition for heart failure preserved ejection fraction, it has been almost disheartening over the last several years that we have not had very specific effective therapies to treat that condition. Now, it is a tremendous boon that we do have medicines interestingly focused on metabolism that are very helpful in that condition for heart failure with preserved ejection fraction. But there is still much more to be understood as far as that condition. I mean, the major challenge with heart failure, as you know, especially with heart failure preserved ejection fraction, it likely is a mix of a wide variety of different etiologies. So in parallel with developing effective therapies that get at some aspect is really understanding what are the individual drivers and then targeting those specific individual drivers. That requires a lot of unbiased discovery work and further profiling to be done. So lot more innovation, but relative to heart failure itself, it is not had widespread recognition as heart failure reduced ejection fraction. So much more to innovate on, for sure.Eric Topol (54:07):Right, right. Yeah, I am stunned by the recent progress in cardiovascular medicine. You have been center stage with a lot of it, and we've had a chance to review so much. And speaking of genetics, I wanted to just get a little insight because I recently came across the fact that your mother here at the City of Hope in Southern California is another famous researcher. And is that, I don't know what chromosome that is on regarding parental transmission of leading research. Maybe you can tell me about that.Pradeep Natarajan (54:41):Yeah, I mean, I guess it is a heritable trait when a parent has one profession that there is a higher likelihood that the offspring will have something similar. So both of my parents are PhDs, nonphysicians. There is a diabetes department at the City of Hope, so she's the chair of that department. So very active. We do overlap in some circles because she does investigate both vascular complications and renal complications. And then sometimes will ask my advice on some visualization. But she herself has just had a science translational medicine paper, for example, just a couple of months ago. So it's fun to talk about these things. To be honest, because my parents are researchers, I was not totally sure that I would be a researcher and kind of wanted to do something different in medicine. But many of my early observations and just how common cardiovascular disease is around me and in my community and wanting to do something useful is what got me specifically into cardiology.(55:45):But obviously there are numerous outstanding, important questions. And as I went through my career, really focused on more basic investigations of atherosclerosis and lipids. What got me excited sort of after my clinical training was the ability to ask many of these questions now in human populations with many new biological data sets, at least first centered on genetics. And the capabilities continue to expand, so now I teach first year Harvard medical students in their genetics curriculum. And when I talk to them just about my career arc, I do remind them they're all doing millions of things and they're exploring lots of things, but when they get to my shoes, the capabilities will be tremendously different. And so, I really advise them to take the different experiences, mainly in an exercise for asking questions, thoughtfully addressing questions, connecting it back to important clinical problems. And then once they start to understand that with a few different approaches, then they'll totally take off with what the opportunities are down the road.Eric Topol (56:51):No, it's great. I mean, how lucky somebody could be in the first year of med school with you as their teacher and model. Wow. Pradeep, we've really gone deep on this and it's been fun. I mean, if there's one person I'm going to talk to you about cardiovascular risk factors and the things that we've been into today, you would be the one. So thank you for taking the time and running through a lot of material here today, and all your work with great interest.Pradeep Natarajan (57:24):Thanks, Eric. I really appreciate it. It's tremendous honor. I'm a big fan, so I would be glad to talk about any of these things and more anytime.***************Thanks for listening, reading or watching!The Ground Truths newsletters and podcasts are all free, open-access, without ads.Please share this post/podcast with your friends and network if you found it informative!Voluntary paid subscriptions all go to support Scripps Research. Many thanks for that—they greatly helped fund our summer internship programs for 2023 and 2024.Thanks to my producer Jessica Nguyen and Sinjun Balabanoff for audio and video support at Scripps Research.Note: you can select preferences to receive emails about newsletters, podcasts, or all I don't want to bother you with an email for content that you're not interested in. Get full access to Ground Truths at erictopol.substack.com/subscribe

Ground Truths
Tom Cech: RNA Takes Center Stage

Ground Truths

Play Episode Listen Later Jun 5, 2024 49:04


In this podcast, Thomas Czech, Distinguished Professor at the University of Colorado, Boulder, with a lineage of remarkable contributions on RNA, ribozyme, and telomeres, discuss why RNA is so incredibly versatile.Video snippet from our conversation. Full videos of all Ground Truths podcasts can be seen on YouTube here. The audios are also available on Apple and Spotify.Transcript with links to the audio and external linksEric Topol (00:07):Well, hello, this is Eric Topol from Ground Truths, and it's really a delight for me to welcome Tom Cech who just wrote a book, the Catalyst, and who is a Nobel laureate for his work in RNA. And is at the University of Colorado Boulder as an extraordinary chemist and welcome Tom.Tom Cech (00:32):Eric, I'm really pleased to be here.The RNA GuyEric Topol (00:35):Well, I just thoroughly enjoyed your book, and I wanted to start out, if I could, with a quote, which gets us right off the story here, and let me just get to it here. You say, “the DNA guy would need to become an RNA guy. Though I didn't realize it at the time, jumping ship would turn out to be the most momentous decision in my life.” Can you elaborate a bit on that?Tom Cech (01:09):As a graduate student at Berkeley, I was studying DNA and chromosomes. I thought that DNA was king and really somewhat belittled the people in the lab next door who were working on RNA, I thought it was real sort of second fiddle material. Of course, when RNA is acting just as a message, which is an important function, a critical function in all life on earth, but still, it's a function that's subservient to DNA. It's just copying the message that's already written in the playbook of DNA. But little did I know that the wonders of RNA were going to excite me and really the whole world in unimaginable ways.Eric Topol (02:00):Well, they sure have, and you've lit up the world well before you had your Nobel Prize in 1989 was Sid Altman with ribozyme. And I think one of the things that struck me, which are so compelling in the book as I think people might know, it's divided in two sections. The first is much more on the biology, and the second is much more on the applications and how it's changing the world. We'll get into it particularly in medicine, but the interesting differentiation from DNA, which is the one trick pony, as you said, all it does is store stuff. And then the incredible versatility of RNA as you discovered as a catalyst, that challenging dogma, that proteins are supposed to be the only enzymes. And here you found RNA was one, but also so much more with respect to genome editing and what we're going to get into here. So I thought what we might get into is the fact that you kind of went into the scum of the pond with this organism, which by the way, you make a great case for the importance of basic science towards the end of the book. But can you tell us about how you, and then of course, many others got into the Tetrahymena thermophila, which I don't know that much about that organism.Tom Cech (03:34):Yeah, it's related to Tetrahymena is related to paramecium, which is probably more commonly known because it's an even larger single celled animal. And therefore, in an inexpensive grade school microscope, kids can look through and see these ciliated protozoa swimming around on a glass slide. But I first learned about them when I was a postdoc at MIT and I would drive down to Joe Gall's lab at Yale University where Liz Blackburn was a postdoc at the time, and they were all studying Tetrahymena. It has the remarkable feature that it has 10,000 identical copies of a particular gene and for a higher organism, one that has its DNA in the nucleus and does its protein synthesis in the cytoplasm. Typically, each gene's present in two copies, one from mom, one from dad. And if you're a biochemist, which I am having lots of stuff is a real advantage. So 10,000 copies of a particular gene pumping out RNA copies all the time was a huge experimental advantage. And that's what I started working on when I started my own lab at Boulder.Eric Topol (04:59):Well, and that's where, I guess the title of the book, the Catalyst ultimately, that grew into your discovery, right?Tom Cech (05:08):Well, at one level, yes, but I also think that the catalyst in a more general conversational sense means just facilitating life in this case. So RNA does much more than just serve as a biocatalyst or a message, and we'll get into that with genome editing and with telomerase as well.The Big Bang and 11 Nobel Prizes on RNA since 2000Eric Topol (05:32):Yes, and I should note that as you did early in the book, that there's been an 11 Nobel prize awardees since 2000 for RNA work. And in fact, we just had Venki who I know you know very well as our last podcast. And prior to that, Kati Karikó, Jennifer Doudna who worked in your lab, and the long list of people working RNA in the younger crowd like David Liu and Fyodor Urnov and just so many others, we need to have an RNA series because it's just exploding. And that one makes me take you back for a moment to 2007. And when I was reading the book, it came back to me about the Economist cover. You may recall almost exactly 17 years ago. It was called the Biology's Big Bang – Unravelling the secrets of RNA. And in that, there was a notable quote from that article. Let me just get to that. And it says, “it is probably no exaggeration to say that biology is now undergoing its neutron moment.”(06:52):This is 17 years ago. “For more than half a century the fundamental story of living things has been a tale of the interplay between genes, in the form of DNA, and proteins, which is genes encode and which do the donkey work of keeping living organisms living. The past couple of years, 17 years ago, however, has seen the rise and rise of a third type of molecule, called RNA.” Okay, so that was 2007. It's pretty extraordinary. And now of course we're talking about the century of biology. So can you kind of put these last 17 years in perspective and where we're headed?Tom Cech (07:34):Well, Eric, of course, this didn't all happen in one moment. It wasn't just one big bang. And the scientific community has been really entranced with the wonders of RNA since the 1960s when everyone was trying to figure out how messenger RNA stored the genetic code. But the general public has been really kept in the dark about this, I think. And as scientists, were partially to blame for not reaching out and sharing what we have found with them in a way that's more understandable. The DNA, the general public's very comfortable with, it's the stuff of our heredity. We know about genetic diseases, about tracing our ancestry, about solving crimes with DNA evidence. We even say things like it's in my DNA to mean that it's really fundamental to us. But I think that RNA has been sort of kept in the closet, and now with the mRNA vaccines against Covid-19, at least everyone's heard of RNA. And I think that that sort of allowed me to put my foot in the door and say, hey, if you were curious about the mRNA vaccines, I have some more stories for you that you might be really interested in.RNA vs RNAEric Topol (09:02):Yeah, well, we'll get to that. Maybe we should get to that now because it is so striking the RNA versus RNA chapter in your book, and basically the story of how this RNA virus SARS-CoV-2 led to a pandemic and it was fought largely through the first at scale mRNA nanoparticle vaccine package. Now, that takes us back to some seminal work of being able to find, giving an mRNA to a person without inciting massive amount of inflammation and the substitution of pseudouridine or uridine in order to do that. Does that really get rid of all the inflammation? Because obviously, as you know, there's been some negativism about mRNA vaccines for that and also for the potential of not having as much immune cell long term activation. Maybe you could speak to that.Tom Cech (10:03):Sure. So the discovery by Kati Karikó and Drew Weissman of the pseudouridine substitution certainly went a long way towards damping down the immune response, the inflammatory response that one naturally gets with an RNA injection. And the reason for that is that our bodies are tuned to be on the lookout for foreign RNA because so many viruses don't even mess with DNA at all. They just have a genome made of RNA. And so, RNA replicating itself is a danger sign. It means that our immune system should be on the lookout for this. And so, in the case of the vaccination, it's really very useful to dampen this down. A lot of people thought that this might make the mRNA vaccines strange or foreign or sort of a drug rather than a natural substance. But in fact, modified nucleotides, nucleotides being the building blocks of RNA, so these modified building blocks such as pseudoU, are in fact found in natural RNAs more in some than in others. And there are about 200 modified versions of the RNA building blocks found in cells. So it's really not an unusual modification or something that's all that foreign, but it was very useful for the vaccines. Now your other question Eric had to do with the, what was your other question, Eric?Eric Topol (11:51):No, when you use mRNA, which is such an extraordinary way to get the spike protein in a controlled way, exposed without the virus to people, and it saved millions of lives throughout the pandemic. But the other question is compared to other vaccine constructs, there's a question of does it give us long term protective immunity, particularly with T cells, both CD8 cytotoxic, maybe also CD4, as I know immunology is not your main area of interest, but that's been a rub that's been put out there, that it isn't just a weaning of immunity from the virus, but also perhaps that the vaccines themselves are not as good for that purpose. Any thoughts on that?Tom Cech (12:43):Well, so my main thought on that is that this is a property of the virus more than of the vaccine. And respiratory viruses are notoriously hard to get long-term immunity. I mean, look at the flu virus. We have to have annual flu shots. If this were like measles, which is a very different kind of virus, one flu shot would protect you against at least that strain of flu for the rest of your life. So I think the bad rap here is not the vaccine's fault nearly as much as it's the nature of respiratory viruses.RNA And Aging Eric Topol (13:27):No, that's extremely helpful. Now, let me switch to an area that's really fascinating, and you've worked quite a bit on the telomerase story because this is, as you know, being pursued quite a bit, has thought, not just because telomeres might indicate something about biologic aging, but maybe they could help us get to an anti-aging remedy or whatever you want to call it. I'm not sure if you call it a treatment, but tell us about this important enzyme, the role of the RNA building telomeres. And maybe you could also connect that with what a lot of people might not be familiar with, at least from years ago when they learned about it, the Hayflick limit.Tom Cech (14:22):Yes. Well, Liz Blackburn and Carol Greider got the Nobel Prize for the discovery of telomerase along with Jack Szostak who did important initial work on that system. And what it does is, is it uses an RNA as a template to extend the ends of human chromosomes, and this allows the cell to keep dividing without end. It gives the cell immortality. Now, when I say immortality, people get very excited, but I'm talking about immortality at the cellular level, not for the whole organism. And in the absence of a mechanism to build out the ends of our chromosomes, the telomeres being the end of the chromosome are incompletely replicated with each cell division. And so, they shrink over time, and when they get critically short, they signal the cell to stop dividing. This is what is called the Hayflick limit, first discovered by Leonard Hayflick in Philadelphia.(15:43):And he, through his careful observations on cells, growing human cells growing in Petri dishes, saw that they could divide about 50 times and then they wouldn't die. They would just enter a state called senescence. They would change shape, they would change their metabolism, but they would importantly quit dividing. And so, we now see this as a useful feature of human biology that this protects us from getting cancer because one of the hallmarks of cancer is immortality of the tumor cells. And so, if you're wishing for your telomeres to be long and your cells to keep dividing, you have to a little bit be careful what you wish for because this is one foot in the door for cancer formation.Eric Topol (16:45):Yeah, I mean, the point is that it seems like the body and the cell is smart to put these cells into the senescent state so they can't divide anymore. And one of the points you made in the book that I think is worth noting is that 90% of cancers have the telomerase, how do you say it?Tom Cech (17:07):Telomerase.Eric Topol (17:08):Yeah, reactivate.Tom Cech (17:09):Right.Eric Topol (17:10):That's not a good sign.Tom Cech (17:12):Right. And there are efforts to try to target telomerase enzyme for therapeutic purposes, although again, it's tricky because we do have stem cells in our bodies, which are the exception to the Hayflick limit rule. They do still have telomerase, they still have to keep dividing, maybe not as rapidly as a cancer cell, but they still keep dividing. And this is critical for the replenishment of certain worn out tissues in our such as skin cells, such as many of our blood cells, which may live only 30 days before they poop out. That's a scientific term for needing to be replenished, right?Eric Topol (18:07):Yeah. Well, that gets me to the everybody's, now I got the buzz about anti-aging, and whether it's senolytics to get rid of these senescent cells or whether it's to rejuvenate the stem cells that are exhausted or work on telomeres, all of these seem to connect with a potential or higher risk of cancer. I wonder what your thoughts are as we go forward using these various biologic constructs to be able to influence the whole organism, the whole human body aging process.Tom Cech (18:47):Yes. My view, and others may disagree is that aging is not an affliction. It's not a disease. It's not something that we should try to cure, but what we should work on is having a healthy life into our senior years. And perhaps you and I are two examples of people who are at that stage of our life. And what we would really like is to achieve, is to be able to be active and useful to society and to our families for a long period of time. So using the information about telomerase, for example, to help our stem cells stay healthy until we are, until we're ready to cash it in. And for that matter on the other side of the coin, to try to inhibit the telomerase in cancer because cancer, as we all know, is a disease of aging, right? There are young people who get cancer, but if you look at the statistics, it's really heavily weighted towards people who've been around a long time because mutations accumulate and other damage to cells that would normally protect against cancer accumulates. And so, we have to target both the degradation of our stem cells, but also the occurrence of cancer, particularly in the more senior population. And knowing more about RNA is really helpful in that regard.RNA DrugsEric Topol (20:29):Yeah. Well, one of the things that comes across throughout the book is versatility of RNA. In fact, you only I think, mentioned somewhere around 12 or 14 of these different RNAs that have a million different shapes, and there's so many other names of different types of RNAs. It's really quite extraordinary. But one of the big classes of RNAs has really hit it. In fact, this week there are two new interfering RNAs that are having extraordinary effects reported in the New England Journal on all the lipids, abnormal triglycerides and LDL cholesterol, APOC3. And can you talk to us about this interfering the small interfering RNAs and how they become, you've mentioned in the book over 400 RNAs are in the clinic now.Tom Cech (21:21):Yeah, so the 400 of course is beyond just the siRNAs, but these, again, a wonderful story about how fundamental science done just to understand how nature works without any particular expectation of a medical spinoff, often can have the most phenomenal and transformative effects on medicine. And this is one of those examples. It came from a roundworm, which is about the size of an eyelash, which a scientist named Sydney Brenner in England had suggested would be a great experimental organism because the entire animal has only about a thousand cells, and it's transparent so we can look at, see where the cells are, we can watch the worm develop. And what Andy Fire and Craig Mello found in this experimental worm was that double-stranded RNA, you think about DNA is being double-stranded and RNA as being single stranded. But in this case, it was an unusual case where the RNA was forming a double helix, and these little pieces of double helical RNA could turn off the expression of genes in the worm.(22:54):And that seemed remarkable and powerful. But as often happens in biology, at least for those of us who believe in evolution, what goes for the worm goes for the human as well. So a number of scientists quickly found that the same process was going on in the human body as a natural way of regulating the expression of our genes, which means how much of a particular gene product is actually going to be made in a particular cell. But not only was it a natural process, but you could introduce chemically synthesized double helical RNAs. There are only 23 base pairs, 23 units of RNA long, so they're pretty easy to chemically synthesize. And that once these are introduced into a human, the machinery that's already there grabs hold of them and can be used to turn off the expression of a disease causing RNA or the gene makes a messenger RNA, and then this double-stranded RNA can suppress its action. So this has become the main company that is known for doing this is Alnylam in Boston, Cambridge. And they have made quite a few successful products based on this technology.Eric Topol (24:33):Oh, absolutely. Not just for amyloidosis, but as I mentioned these, they even have a drug that's being tested now, as you know that you could take once or twice a year to manage your blood pressure. Wouldn't that be something instead of a pill every day? And then of course, all these others that are not just from Alnylam, but other companies I wasn't even familiar with for managing lipids, which is taking us well beyond statins and these, so-called PCSK9 monoclonal antibodies, so it's really blossoming. Now, the other group of RNA drugs are antisense drugs, and it seemed like they took forever to warm up, and then finally they hit. And can you distinguish the antisense versus the siRNA therapeutics?Tom Cech (25:21):Yes, in a real general sense, there's some similarity as well as some differences, but the antisense, what are called oligonucleotides, whoa, that's a big word, but oligo just means a few, right? And nucleotides is just the building blocks of nucleic acid. So you have a string of a few of these. And again, it's the power of RNA that it is so good at specifically base pairing only with matching sequences. So if you want to match with a G in a target messenger RNA, you put a C in the antisense because G pairs with C, if you want to put an A, if want to match with an A, you put a U in the antisense because A and U form a base pair U is the RNA equivalent of T and DNA, but they have the same coding capacity. So any school kid can write out on a notepad or on their laptop what the sequence would have to be of an antisense RNA to specifically pair with a particular mRNA.(26:43):And this has been, there's a company in your neck of the woods in the San Diego area. It started out with the name Isis that turned out to be the wrong Egyptian God to name your company after, so they're now known as Ionis. Hopefully that name will be around for a while. But they've been very successful in modifying these antisense RNAs or nucleic acids so that they are stable in the body long enough so that they can pair with and thereby inhibit the expression of particular target RNAs. So it has both similarities and differences from the siRNAs, but the common denominator is RNA is great stuff.RNA and Genome EditingEric Topol (27:39):Well, you have taken that to in catalyst, the catalyst, you've proven that without a doubt and you and so many other extraordinary scientists over the years, cumulatively. Now, another way to interfere with genes is editing. And of course, you have a whole chapter devoted to not just well CRISPR, but the whole genome editing field. And by the way, I should note that I forgot because I had read the Codebreaker and we recently spoke Jennifer Doudna and I, that she was in your lab as a postdoc and you made some wonderful comments about her. I don't know if you want to reflect about having Jennifer, did you know that she was going to do some great things in her career?Tom Cech (28:24):Oh, there was no question about it, Eric. She had been a star graduate student at Harvard, had published a series of breathtaking papers in magazines such as Science and Nature already as a graduate student. She won a Markey fellowship to come to Colorado. She chose a very ambitious project trying to determine the molecular structures of folded RNA molecules. We only had one example at the time, and that was the transfer RNA, which is involved in protein synthesis. And here she was trying these catalytic RNAs, which we had discovered, which were much larger than tRNA and was making great progress, which she finished off as an assistant professor at Yale. So what the general public may not know was that in scientific, in the scientific realm, she was already highly appreciated and much awarded before she even heard anything about CRISPR.Eric Topol (29:38):Right. No, it was a great line you have describing her, “she had an uncanny talent for designing just the right experiment to test any hypothesis, and she possessed more energy and drive than any scientist I'd ever met.” That's pretty powerful. Now getting into CRISPR, the one thing, it's amazing in just a decade to see basically the discovery of this natural system to then be approved by FDA for sickle cell disease and beta thalassemia. However, the way it exists today, it's very primitive. It's not actually fixing the gene that's responsible, it's doing a workaround plan. It's got double strand breaks in the DNA. And obviously there's better ways of editing, which are going to obviously involve RNA epigenetic editing, if you will as well. What is your sense about the future of genome editing?Tom Cech (30:36):Yeah, absolutely, Eric. It is primitive right now. These initial therapies are way too expensive as well to make them broadly applicable to the entire, even in a relatively wealthy country like the United States, we need to drive the cost down. We need to get them to work, we need to get the process of introducing them into the CRISPR machinery into the human body to be less tedious and less time consuming. But you've got to start somewhere. And considering that the Charpentier and Doudna Nobel Prize winning discovery was in 2012, which is only a dozen years ago, this is remarkable progress. More typically, it takes 30 years from a basic science discovery to get a medical product with about a 1% chance of it ever happening. And so, this is clearly a robust RNA driven machine. And so, I think the future is bright. We can talk about that some more, but I don't want to leave RNA out of this conversation, Eric. So what's cool about CRISPR is its incredible specificity. Think of the human genome as a million pages of text file on your computer, a million page PDF, and now CRISPR can find one sentence out of that million pages that matches, and that's because it's using RNA, again, the power of RNA to form AU and GC base pairs to locate just one site in our whole DNA, sit down there and direct this Cas9 enzyme to cut the DNA at that site and start the repair process that actually does the gene editing.Eric Topol (32:41):Yeah, it's pretty remarkable. And the fact that it can be so precise and it's going to get even more precise over time in terms of the repair efforts that are needed to get it back to an ideal state. Now, the other thing I wanted to get into with you a bit is on the ribosome, because that applies to antibiotics and as you call it, the mothership. And I love this metaphor that you had about the ribosome, and in the book, “the ribosome is your turntable, the mRNA is the vinyl LP record, and the protein is the music you hear when you lower the needle.” Tell us more about the ribosome and the role of antibiotics.Tom Cech (33:35):So do you think today's young people will understand that metaphor?Eric Topol (33:40):Oh, they probably will. They're making a comeback. These records are making a comeback.Tom Cech (33:44):Okay. Yes, so this is a good analogy in that the ribosome is so versatile it's able to play any music that you feed at the right messenger RNA to make the music being the protein. So you can have in the human body, we have tens of thousands of different messenger RNAs. Each one threads through the same ribosome and spills out the production of whatever protein matches that mRNA. And so that's pretty remarkable. And what Harry Noller at UC Santa Cruz and later the crystallographers Venki Ramakrishnan, Tom Steitz, Ada Yonath proved really through their studies was that this is an RNA machine. It was hard to figure that out because the ribosome has three RNAs and it has dozens of proteins as well. So for a long time people thought it must be one of those proteins that was the heart and soul of the record player, so to speak.RNA and Antibiotics(34:57):And it turned out that it was the RNA. And so, when therefore these scientists, including Venki who you just talked to, looked at where these antibiotics docked on the ribosome, they found that they were blocking the key functional parts of the RNA. So it was really, the antibiotics knew what they were doing long before we knew what they were doing. They were talking to and obstructing the action of the ribosomal RNA. Why is this a good thing for us? Because bacterial ribosomes are just enough different from human ribosomes that there are drugs that will dock to the bacterial ribosomal RNA, throw a monkey wrench into the machine, prevent it from working, but the human ribosomes go on pretty much unfazed.Eric Topol (36:00):Yeah, no, the backbone of our antibiotics relies on this. So I think people need to understand about the two subunits, the large and the small and this mothership, and you illuminate that so really well in the book. That also brings me to phage bacteria phage, and we haven't seen that really enter the clinic in a significant way, but there seems to be a great opportunity. What's your view about that?Tom Cech (36:30):This is an idea that goes way back because since bacteria have their own viruses which do not infect human cells, why not repurpose those into little therapeutic entities that could kill, for example, what would we want to kill? Well, maybe tuberculosis has been very resistant to drugs, right? There are drug resistant strains of TB, yes, of TB, tuberculosis, and especially in immunocompromised individuals, this bug runs rampant. And so, I don't know the status of that. It's been challenging, and this is the way that biomedicine works, is that for every 10 good ideas, and I would say phage therapy for bacterial disease is a good idea. For every 10 such ideas, one of them ends up being practical. And the other nine, maybe somebody else will come along and find a way to make it work, but it hasn't been a big breakthrough yet.RNA, Aptamers and ProteinsEric Topol (37:54):Yeah, no, it's really interesting. And we'll see. It may still be in store. What about aptamers? Tell us a little bit more about those, because they have been getting used a lot in sorting out the important plasma proteins as therapies. What are aptamers and what do you see as the future in that regard?Tom Cech (38:17):Right. Well, in fact, aptamers are a big deal in Boulder because Larry Gold in town was one of the discoverers has a company making aptamers to recognize proteins. Jack Szostak now at University of Chicago has played a big role. And also at your own institution, Jerry Joyce, your president is a big aptamer guy. And you can evolution, normally we think about it as happening out in the environment, but it turns out you can also make it work in the laboratory. You can make it work much faster in the laboratory because you can set up test tube experiments where molecules are being challenged to perform a particular task, like for example, binding to a protein to inactivate it. And if you make a large community of RNA molecules randomly, 99.999% of them aren't going to know how to do this. What are the odds? Very low.(39:30):But just by luck, there will be an occasional molecule of RNA that folds up into a shape that actually fits into the proteins active sighting throws a monkey wrench into the works. Okay, so now that's one in a billion. How are you going to find that guy? Well, this is where the polymerase chain reaction, the same one we use for the COVID-19 tests for infection comes into play. Because if you can now isolate this needle in a haystack and use PCR to amplify it and make a whole handful of it, now you've got a whole handful of molecules which are much better at binding this protein than the starting molecule. And now you can go through this cycle several times to enrich for these, maybe mutagen it a little bit more to give it a little more diversity. We all know diversity is good, so you put a little more diversity into the population and now you find some guy that's really good at recognizing some disease causing protein. So this is the, so-called aptamer story, and they have been used therapeutically with some success, but diagnostically certainly they are extremely useful. And it's another area where we've had success and the future could hold even more success.Eric Topol (41:06):I think what you're bringing up is so important because the ability to screen that tens of thousands of plasma proteins in a person and coming up with as Tony Wyss-Coray did with the organ clocks, and this is using the SomaLogic technology, and so much is going on now to get us not just the polygenic risk scores, but also these proteomic scores to compliment that at our orthogonal, if you will, to understand risk of people for diseases so we can prevent them, which is fulfilling a dream we've never actually achieved so far.Tom Cech (41:44):Eric, just for full disclosure, I'm on the scientific advisory board of SomaLogic in Boulder. I should disclose that.Eric Topol (41:50):Well, that was smart. They needed to have you, so thank you for mentioning that. Now, before I wrap up, well, another area that is a favorite of mine is citizen science. And you mentioned in the book a project because the million shapes of RNA and how it can fold with all hairpin terms turns and double stranded and whatever you name it, that there was this project eteRNA that was using citizen scientists to characterize and understand folding of RNA. Can you tell us about that?RNA Folding and Citizen ScienceTom Cech (42:27):So my friend Rhiju Das, who's a professor at Stanford University, sort of adopted what had been done with protein folding by one of his former mentors, David Baker in Seattle, and had repurposed this for RNA folding. So the idea is to come up with a goal, a target for the community. Can you design an RNA that will fold up to look like a four pointed cross or a five pointed star? And it turned out that, so they made it into a contest and they had tens of thousands of people playing these games and coming up with some remarkable solutions. But then they got a little bit more practical, said, okay, that was fun, but can we have the community design something like a mRNA for the SARS-CoV-2 spike protein to make maybe a more stable vaccine? And quite remarkably, the community of many of whom are just gamers who really don't know much about what RNA does, were able to find some solutions. They weren't enormous breakthroughs, but they got a several fold, several hundred percent increase in stability of the RNA by making it fold more tightly. So I just find it to be a fascinating approach to science. Somebody of my generation would never think of this, but I think for today's generation, it's great when citizens can become involved in research at that level.Eric Topol (44:19):Oh, I think it's extraordinary. And of course, there are other projects folded and others that have exemplified this ability for people with no background in science to contribute in a meaningful way, and they really enjoy, it's like solving a puzzle. The last point is kind of the beginning, the origin of life, and you make a pretty strong case, Tom, that it was RNA. You don't say it definitively, but maybe you can say it here.RNA and the Origin of LifeTom Cech (44:50):Well, Eric, the origin of life happening almost 4 billion years ago on our primitive planet is sort of a historical question. I mean, if you really want to know what happened then, well, we don't have any video surveillance of those moments. So scientists hate to ever say never, but it's hard to sort of believe how we would ever know for sure. So what Leslie Orgel at the Salk Institute next to you taught me when I was a starting assistant professor is even though we'll never know for sure, if we can recapitulate in the laboratory plausible events that could have happened, and if they make sense chemically and biologically, then that's pretty satisfying, even if we can never be absolutely sure. That's what a number of scientists have done in this field is to show that RNA is sort of a, that all the chemistry sort of points to RNA as being something that could have been made under prebiotic conditions and could have folded up into a way that could solve the greatest of all chicken and egg problems, which came first, the informational molecule to pass down to the next generation or the active molecule that could copy that information.(46:32):So now that we know that RNA has both of those abilities, maybe at the beginning there was just this RNA world RNA copying itself, and then proteins came along later, and then DNA probably much more recently as a useful but a little bit boring of genetic information, right?Eric Topol (46:59):Yeah. Well, that goes back to that cover of the Economist 17 years ago, the Big Bang, and you got me convinced that this is a pretty strong story and candidate. Now what a fun chance to discuss all this with you in an extraordinary book, Tom. Did I miss anything that you want to bring up?Tom Cech (47:21):Eric, I just wanted to say that I not only appreciate our conversation, but I also appreciate all you are doing to bring science to the non-scientist public. I think people like me who have taught a lot of freshmen in chemistry, general chemistry, sort of think that that's the level that we need to aim at. But I think that those kids have had science in high school year after year. We need to aim at the parents of those college freshmen who are intelligent, who are intellectually curious, but have not had science courses in a long time. And so, I'm really joining with you in trying to avoid jargon as much as possible. Use simple language, use analogies and metaphors, and try to share the excitement of what we're doing in the laboratory with the populace.Eric Topol (48:25):Well, you sure did that it was palpable. And I thought about it when I read the book about how lucky it would be to be a freshman at the University of Boulder and be having you as the professor. My goodness. Well, thank you so much. This has been so much fun, Tom, and I hope everybody's going to get out there and read the Catalyst to get all the things that we didn't even get a chance to dive into. But this has been great and look forward to future interactions with you.Tom Cech (48:53):Take care, Eric.*********************Thanks for listening or reading this edition of Ground Truths.Please share this podcast with your friends and network. That tells me you found it informative and makes the effort in doing these worthwhile.All Ground Truths newsletters and podcast are free. Voluntary paid subscriptions all go to support Scripps Research. Many thanks for that—they greatly helped fund our summer internship programs for 2023 and 2024.Thanks to my producer Jessica Nguyen and Sinjun Balabanoff for audio and video support at Scripps Research.Note: you can select preferences to receive emails about newsletters, podcasts, or all I don't want to bother you with an email for content that you're not interested in. Get full access to Ground Truths at erictopol.substack.com/subscribe

The G Word
Vivienne Parry, Louise Fish and Professor Matt Brown: Celebrating genomic breakthroughs - Insights from the Festival of Genomics

The G Word

Play Episode Listen Later Feb 15, 2024 36:27


In January we saw experts from across the genomics ecosystem, including patients and those with an interest in genomics, gather at the Festival of Genomics - the UK's largest annual life sciences event. In this episode, our host, Vivienne Parry, Head of Engagement at Genomics England, speaks to Louise Fish, CEO of Genetic Alliance UK, and Professor Matt Brown, Chief Scientific Officer at Genomics England, to discuss the event and emerging future trends in genomics.  In this episode you'll also hear some exciting future advances in genomics research from some eminent speakers at the Festival: Harold Sneider, Professor of Genetic Epidemiology, University Medical Center Groningen sheds light on the "Identification of methylation markers for Type 2 diabetes up to 10 years before disease onset." Nagy Habib, Professor of Surgery, Imperial College London, delves into "The future of saRNA therapeutics and its potential for treatment".  Lennard Lee, National Clinical Advisor on innovation and cancer vaccines, presents his perspectives on "The Future of Cancer Vaccines," offering a glimpse into the promising advancements in this critical field. "The scientific breakthroughs that are being made are absolutely incredible and they're really exciting, but from the point of someone living with a genetic condition, what they want to see is those scientific breakthroughs making a real difference in the clinics...For some conditions, it's about treatments, but it's also about being able to get a diagnosis faster, to be able to understand what condition is impacting on you, how it might affect you over your lifetime and your wider family, and to be able to work with NHS services to understand and plan for the care and treatment that you'll need throughout your lifetime."   You can read the transcript below or download it here: https://files.genomicsengland.co.uk/documents/Podcast-transcripts/Insights-from-the-Festival-of-Genomics.docx   Vivienne Parry: Hello and welcome to the G Word. Vivienne Parry: The Festival of Genomics is the UK's biggest genomics event, and it's become an essential part of our year. It's free for 90% of its delegates, it's in person, and with more than 5,000 people expected, it's now so big that it's had to move to ExCel's cavernous Dockland Halls. It's the place to hear top science and to spot new trends, but actually for me the joy of the festival is the people you meet. Of course, it's great to catch up with old friends, but it's the new collaborations sparked by random encounters at the festival which I think are the lifeblood of the genomics ecosystem, and everyone with an interest in genomics is here, patients, clinicians from the NHS, researchers, industry, policymakers, and the G Word. What we thought we'd do is bring you a flavour of this great event from the floor of the ExCel halls, and give you a quick soundbite from three of the speakers that we felt best exemplify the future of genomics. With me to discuss the event and future trends in genomics, Professor Matt Brown, Genomic England's chief scientific officer, and Louise Fish, CEO of the Genetic Alliance UK, which as its name suggests, is an alliance of over 200 organisations reflecting the needs and concerns of those affected by genetic conditions. My name's Vivienne Parry, I'm head of public engagement at Genomics England, and I'm delighted to be your host for today's pod from the Festival of Genomics. Welcome to you both. So, let's start with you, Matt. How important is the Festival of Genomics for genomics in the UK? Matt Brown: Well, the Festival of Genomics has become a really key meeting for the genomics community in the UK, and I think increasingly in Europe as well. It's a really large, high quality event that brings together commercial and academic and biotech companies in the one forum, and I think it's a really exciting programme. Vivienne Parry: And of course, Louise, it's open to patients as well, which makes it an unusual event. Louise Fish: Absolutely, and it's brilliant to have patients and families here. So, people living with genetic conditions clearly need to be part of the debate when we're talking about developing new services, and developing new treatments and diagnostics, so it's absolutely fantastic to be able to come together in one room with people from the NHS and the broader sector. Vivienne Parry: And it's grown enormously, and I guess that reflects, as much as anything else, just how exciting genomics is. Matt, I'm going to pin you to the ground [laughter] and say, why is it so exciting in genomics at the moment? Matt Brown: Look, the field's really hitting its tracks. We're seeing advances in technology, analytics, application in the clinical space, and of course booming commercial activity associated with that. But from a situation ten years ago, where we had research capability for using genomics to assist in diagnosis and cancer profiling, now we're in a situation where we have multiple different approaches to assist with both of those things, transcriptomics, proteomics, spatial, single cell methods, optical mapping, a whole monopoly of different technologies that have developed out of the research world but are pretty close to being ready for clinical application. Of course, in analytics, the rise of AI and the potential that has for improving interpretation of genomes and improving personalised medicine prediction in cancers and in multivariant data, those are absolutely massive things. But aligned to that, there's also, you know, the growing worldwide application of genomics in clinical spaces, of course led through the UK and the NHS Genomic Medical Service, which has really shown the way for the world about how this might make a difference. Vivienne Parry: And Louise, that's the really exciting thing is we're now seeing not just talk about therapies, we are seeing the therapies for rare disease actually going into clinical trials and into services even. Louise Fish: Yeah, absolutely, and that's why people living with genetic conditions and their families want to see the change. The scientific breakthroughs that are being made are absolutely incredible and they're really exciting, but from the point of someone living with a genetic condition, what they want to see is those scientific breakthroughs making a real difference in the clinics. And that's sometimes about treatments, you know. For some conditions, it's about treatments, but it's also about being able to get a diagnosis faster, to be able to understand what condition is impacting on you, how it might affect you over your lifetime and your wider family, and to be able to work with NHS services to understand and plan for the care and treatment that you'll need throughout your lifetime. So, treatment's one part of it, but actually that ability to better understand what the future will hold for you, and to plan ahead for the care and support that you will need to live your life to the full is what really excites people living with genetic conditions and their families. Vivienne Parry: Now, let's hear the first of our three clips. The programme is absolutely vast, but these were three presentations that we just thought were terrific. Let's hear the first one. Nagy Habib: My name is Professor Nagy Habib. I'm a consultant surgeon at Hammersmith Hospital, Imperial College, London. We are going through a very exciting time, where we know what is the problem with the diseases, and so far we couldn't do anything about it, but suddenly the door is opening and it all came with the RNA vaccine, because we had to go very fast to get a vaccine for covid, to protect the population, and that pushed the science to go very fast, and now we can apply it to other areas apart from covid, like cancer and rare genetic diseases. And these therapeutics are what you and I and everybody else have received during vaccination. There has been six billion injections around the world, so you can imagine that everybody had an RNA injection. And RNA is that molecule between our genome, the DNA, and the protein. For anything to happen in our body, it requires the protein, but there must be an RNA in between. In the past, it was all about DNA, but now it is RNA. Why can't we get a vaccine against cancer? And so now the field is growing very fast for a vaccine for cancer. Now, the way we think about it is that we can have an injection so that we don't develop cancer of the prostate or cancer of the breast and so on, but in actual fact today what we can say is that if we take out a tumour with surgery, and we can take the RNA from the tumour and inject it in the patient, the early clinical trials tell us that this might work, and to stop the tumour coming back. It is very important to make sure that, once the tumour is out, it doesn't come back. And I think there is hope that we can have RNA vaccines in cancer. Now, to treat cancer without surgery, still we have some way to go, but again, now we know that the problem with cancer is that some of our immune cells that are there to defend us from cancer, they change their mind and suddenly they collaborate with the enemy. So instead of helping us, they are destroying our immune system, and we are developing drugs that can stop that from happening to our immune systems. Now, when you really think about what are the diseases that kill people, cancer is definitely very high up. The second one, not in a particular order, but cardiovascular system, we get heart attacks and we die from heart failure, or we get stroke and we die from stroke, and that's because we eat too much. The food is very tasty [laughter]. So, now we have injections, and the injection can make us lose weight, and we lose weight very fast. The problem is again it's very expensive. Who can afford £600 a week? And when you stop the injection, you put on weight again. So, now we are working again with RNA, and we have found a way where you inject only once every six months. And then the final thing, which is really the dream of everybody, is to stop Alzheimer's disease. So, Alzheimer's disease, as we get old, there are toxic materials that are accumulating in our brain cells, and only this year we've got two drugs coming along that can help stopping Alzheimer's disease at an early stage. Now, what we need to do is to bring that it works on all types, even the advance type of Alzheimer's disease, and now there are [inaudible 0:09:26] where we can take it from the nose. So, you inhale it from the nose and it goes straight to the brain, because there is sort of a motorway that connects the roof of the nose with the base of the brain, which is very simple. It doesn't even need an injection in the arm vein. So, it's all very, very exciting. Vivienne Parry: That is so fascinating. It's real future casting. Matt, I mean, I say it's future casting, but tell me a bit about the Rare Therapies Launchpad, because, you know, that picks up some of what Nagy has outlined. Matt Brown: Yeah, so DNA and RNA therapeutics are absolutely booming, and that's one of the big excitements is that we're not only being able to diagnose people, but we're coming up with new ways of actually providing treatments for patients with rare diseases and cancers through nucleic acid therapeutics. For rare diseases, the type of clinical trials that are involved are really quite different, and you can't just basically translate what was used for common diseases into the rare disease space. It just doesn't work, and that's really held back the field a lot. So, to try and enable rare therapies to actually make that leap from a research setting into actual clinical practice, Genomics England, in partnership with the Medical Health Regulatory Authority and others, have set up a Rare Therapies Launchpad, to provide an end to end solution for people to be able to run clinical trials for rare and ultra rare diseases, particularly focusing on nucleic acid therapies, and linking that with both the regulatory authorities and health funding authorities so that we can get these ultimately into clinical practice. I think we need these sorts of initiatives so that we don't continue to see rare therapies falling over because they're being assessed and made to go through the hurdles that common therapies do nowadays. Vivienne Parry: So Louise, we really are in the area of what people call N of 1 medicines. Louise Fish: Yeah, absolutely. So, these are medicines that are made specifically for one person and will help that one person, and obviously that brings a whole heap of possibilities for people living with genetic conditions, but also a load of challenges that we understand for decision makers within the MHRA and NICE and the NHS. And so I think there are some real challenges that we're really aware of from the decisions that are already being made by those decision making authorities about treatment. Obviously, putting it at the most basic level, you don't have the same evidence base for treatment that's just available for one person that you do from a clinical trial, where thousands of people will have taken part in a trial to understand how it affects a whole host of people. So, we know that the decision making bodies are going to need to take a different approach to evidence, so are going to need to be willing to look at evidence that is just from a trial involving one person. They're going to need to be able to extrapolate the benefits of that treatment across someone's lifetime, and that can be challenging, and we've seen that before in rare disease medicines and the new treatments that have come along in recent years. So, there are definitely some challenges, and we're really glad to see those challenges being acknowledged upfront by Genomics England, the MHRA and others, and being debated and discussed, and trying to find solution now rather than waiting for those treatments to come along later, and then trying to retrofit and decide how to manage them. So, it's great to see this debate taking place early, and we're really keen to make sure that the voices of people living with rare conditions and their families are part of that discussion. Vivienne Parry: And the really cheering thing that we're hearing from Professor Habib is that he thinks that the cost is going to be much less, because some of these things, you know, have million pound price tickets, so to have something that will be cheap is really going to be I think the gamechanger.   Louise Fish: One of the challenges with that is understanding the lifetime costs of someone living with a genetic condition and all of the complexities that are involved, and not just the medical care that they need, but the social care and the wraparound care that they'll need, the extra support from schools and colleges, the extra support from employers if they're able to go in employment. So, I think we're constantly trying to help the government and decision makers have a better understanding that those lifetime costs of living with a genetic condition are the things that should be taken into account when they're making decisions about a new treatment that could be totally game changing for someone's health and their future. Vivienne Parry: Cheaper treatments on the way, Matt? Matt Brown: So, I think we absolutely need to work on reducing the costs of these treatments, because at the moment the costs are so high that, were we to extrapolate that out to try and treat the thousands to tens of thousands of different rare diseases that there are out there, we couldn't possibly afford it. I think it's very promising that we will get cheaper treatments. This might come about through reducing the development costs, in particular reducing the clinical trial programmes, and the level of safety and efficacy evidence that you require before you can actually make these treatments available. I think that will make a massive difference, if we can simplify that. And another thing is, by better collaboration between the different rare disease communities and genetic medical services around the world, to make sure that what might be an N equals 1 condition in the United Kingdom, when you consider it around the world, might actually be an N equals 100 people, and then basically the cost per patient drops substantially. To achieve that, we need much better coordination between the national genomic medical services. Vivienne Parry: At the end there, you heard talk of using RNA therapies for obesity and Alzheimer's, and we principally talk, particularly in Genomics England, not just about cancer and rare disease. But I wanted to present to you another presentation, which I just thought was extraordinary, which comes from the Netherlands, and it's about picking up signs of diabetes using genomics ten years in advance. Just listen to this. Harold Sneider: Hi, I'm Harold Sneider, I'm a genetic epidemiologist working at the University Medical Centre in Groningen in the Netherlands, and my focus is on cardiometabolic disease, and I have a great interest in hypertension, for example, obesity, but also type two diabetes. So, one of my major interests is to try and identify genes for common complex, mostly cardiometabolic diseases, so our approach is to do genome-wide association studies using genetics, but also epigenetics. And epigenetics can be screened for so-called methylation markers, and those methylation markers have an effect on expression of the genes, and we can look at this all over the genome. Then a very interesting question came up, whether these types of epigenetic signals or methylation markers could actually be used to predict disease in people that are still healthy. So, the goal of this type of work always consists of two parts. First, it's that we try to find out which genes are highlighted by these DNA methylation markers, because they are located at certain positions on the genome, so we know which genes are involved in those regions and we can learn more about the underlying biological mechanisms that play a role in the development of the disease. Because we found those signals up to ten years before the disease occurred, so that tells us something about changes that already happen at an early stage. It's like an early detection mechanism. At the same time, a combination of these markers together lets you calculate what's called a methylation score that can be used for the prediction of the disease, and the ultimate goal here is that even in healthy individuals, when you have those measurements, you can calculate such a score to improve the prediction and identify people with a higher probability to develop such a disease. I definitely think we can apply this general approach also to other – for example, cardiometabolic diseases, such as coronary artery disease or also hypertension. Vivienne Parry: Harold Sneider there from Groningen. And extraordinary, the idea that you might be able to pick up not just diabetes perhaps ten years in advance, but also he was talking about potential for other lifestyle diseases, like cardiovascular disease, for instance. What are your thoughts about that, Matt? Matt Brown: Look, I think it's always been an aspiration of the clinical community to move treatments from treating patients with established disease to actually working in really early or preclinical spaces, where you've got a much better chance of preventing end organ damage, and secondly you've got a much better chance of actually inducing remissions or potentially actually curing diseases. And I think not just in diabetes, but also in a range of immune mediated diseases, there's pretty good evidence now that you can, by intervening early, really make a massive difference to the natural history of diseases, and new methods are coming about to identify those patients, be it polygenic risk scores or other biomarkers, to enable us to sort of flip the approach of medicine from being reactive to pre-emptive. Vivienne Parry: And rare conditions, as they do so often, Louise, are leading the way in understanding the issues, which will then spill out into a much wider area of the population. Louise Fish: Yeah, absolutely, and rare conditions obviously is the space that we work in. So, Genetic Alliance UK, as you say, is an alliance of around 230 charities that support people largely with rare genetic conditions, and many of those charities are condition specific or look after groups of conditions, like metabolic rare diseases. So, that's the kind of space that we come from, and obviously in our space, the excitement is around the work that we're doing with Genomics England around the Generation Study, and trying to use that to understand whether it's possible to screen babies to understand whether they have a rare genetic condition, and if so to identify that condition and intervene early. And again, excitingly, that's not just about treatment, it's about whether there's a way of helping that child and their family, if you can identify very early to help really improve their lifestyle choices. And one of the best examples we have is identifying children with brittle bone disease, where if you pick them up through screening, you'd be able to teach their parents to handle them safely, so they didn't have breaks in their bones as babies, which is what we see now. So from our perspective, it's obviously different to the polygenic risk scoring, but again it's that idea of using genomics as a way of identifying conditions very early, and intervening before signs and symptoms start, to try and improve the life chances of the person living with that condition, and help their wider family to help them, which is really exciting from our perspective. Vivienne Parry: But the experience and knowledge that you've gained as rare disease organisations actually is enormously valuable to other people. I mean, rare has always been at the forefront. I mean, in cancer, for example, it was chronic myeloid leukaemia, which was a rare cancer, that kind of unlocked cancer targeted treatments for everybody else. And it always seems to me that rare is at the forefront. Although it's often seen to be behind, it actually is the key to unlocking so many other things, and the experiences that you have all had are so valuable for much wider populations. Louise Fish: Yeah, absolutely, and one of the reasons we run Genetic Alliance UK is so our member organisations can learn from one another, ‘cos there's always one of the rare patient organisations which is surging ahead in a particular space, doing something really exciting, doing something really new, and we try and make sure that our members can learn from one another and don't have to kind of reinvent that wheel. But I know that spills out into the wider cancer space and beyond, which is fantastic. Vivienne Parry: And Louise, do you think there are particular conditions which, if I can put it like this, are on a roll at the moment, where genomics is really advancing fast for them? Louise Fish: Oh goodness, that's a really good question. There are lots of conditions where genomics is making a significant difference really quickly. For us, I think we go back to the Generation Study, and at the moment we only screen in this country for nine conditions, soon to be ten with the addition of a new condition, but the Generation Study's looking at 200 conditions and whether it's possible to screen for them. And for all of those 200 conditions, it's a really exciting opportunity to see if we can learn more, both about the potential to understand and develop treatments early, but also just about the chance to understand the natural history of that condition so much earlier than we do at the moment. And I think that's it, it's that understanding of the natural history of the condition really early, and understanding how a family can be helped through all the aspects of the condition, which is giving people most excitement, I think, alongside the potential to develop treatments. And I know we talk about treatments a lot, but at the moment only five percent of rare diseases have a condition specific treatment available, so we really try and balance, within Genetic Alliance UK, that hope for the small number of conditions that do have treatments, which is really exciting, or have treatments in development, and actually making sure that the scientific breakthroughs in genomics are something that all conditions can benefit from, whether there's a treatment or not. The potential for early identification of people with a condition, understanding the natural history better, and wrapping a package of support and care around people that is not just about a drug itself, is really important to us and to all of our members. Vivienne Parry: Matt, are you seeing any particular areas where there's a really rapid success? Matt Brown: Look, I think there have been some absolute standout successes in nucleic acid therapies in recent years. So, one is the treatment of familial hypercholesterolemia, with siRNAs for PCSK9, so the Inclisiran type approach, which has absolutely revolutionised management of that disease. In recent times, I'd highlight, for example, the treatment of sickle cell disease, an absolutely massive global problem, and now we've got a therapy which can really control sickling crisis and make a big difference to a disease which isn't just a disease of developed countries, in fact it's particularly a disease of Africa, of course. On a global level, that's just going to have a huge effect. But I think, yeah, I just would like to come back to that comment you made about things starting with rare diseases. So, in genomics, rare disease genomics has taught us a heck of a lot about what drives common diseases as well, and to my mind, gold dust for drug development companies is where you have genes that are associated with both rare and common forms of the same type of disease. And that tells you that basically you're very likely, through your treatment, to be able to actually influence the disease, and that it will influence a large proportion of patients with the disease. So, I'm really enjoying seeing this division between rare diseases and common diseases broken down a little bit, and a lot more learning in therapies going from one to the other. Vivienne Parry: Let's move to a completely different area, one that's very important to Genomics England and less important, Louise, at the Genetic Alliance UK, which is cancer. We're going to hear from Lennard Lee about cancer vaccine. Lennard Lee: I'm Dr Lennard Lee, I'm a medical oncologist, so I practice as an NHS doctor, treating cancer, and I'm an associate professor at the University of Oxford. We've come to a position whereby vaccines can be developed quicker than anyone thought. In the last few years, we've realised that the technology has moved on rapidly, MRNA technology, and you can make vaccines and update them really, really quickly. We've now come to a situation where vaccines can be made against cancer, and this is where genomics is really starting to supercharge this technology. If you can sequence a cancer then what we're finding now is that the technology now exists for you to print off an MRNA vaccine for that patient, a truly personalised product. And it's amazing because the genetic basis of the cancer, what the genomics sequencing shows then becomes a vaccine itself. The vaccine is designed based on that sequence, and that's why genomics has really supercharged this field of vaccinations for cancer. One of the possible things we just need to clarify and be aware of is that when people talk about cancer vaccines, they mean a number of things. Ultimately, what it involves is getting a new treatment for people with cancer, because it's based on their genetic sequence, so it's used to treat people with cancer. The future's an exciting one, truly personalised medicine based on genomics. Genomics is going through so many different phases in the field of cancer. Firstly, we were starting to understand why cancer happened and what patients outcomes were. The second phase started to kick off where genomics would help patients select the right drugs at the right time for them, which is amazing. And now we've entered the final evolution of genomics, where it now becomes the actual drugs that we treat people with. And cancer vaccine is one of the first potential areas where genomics will start to form the basis of the treatments going ahead. In five years' time, we're going to know if it works or not, where an individual vaccine based on the genomic abnormality seen in that cancer is going to give better outcomes for patients than an off the shelf product. We know that every cancer's different, so genomics has showed us this, but all of a sudden that sequence could become that vaccine, which then primes that immune system, truly personalised therapy. And it is so exciting that we're going to be talking about this in this festival, and it's being driven as from the UK, which has got so much strength in terms of genomic capabilities as we're developing vaccines. Vivienne Parry: So Lennard Lee there, absolutely confident of the importance of cancer vaccines. Matt, what are your thoughts on that?  Matt Brown: I think it's a tremendously exciting field. The early data on cancer vaccines with melanoma, for example, showed that for a cancer which previously had been resistant to virtually all of our approaches, is actually quite responsive to novel cancer vaccine approaches. We are yet to see across what diversity of cancers this is actually going to work, so there's clearly a huge clinical trial programme that's going to be required to drive this, and the UK is playing a really central role through the Cancer Vaccines Launchpad that Lennard's involved with running, in creating the evidence base about whether these are going to achieve the promise that they hold. I also think that they've got a lot of possibility for inherited cancer types. For example, I think the programme's looking at cancer vaccines for Lynch syndrome, to try and prevent colorectal cancer in that group of patients. So, I think they've got lots and lots of opportunities, and it's nice to see something positive actually coming out of the pandemic like this, for what was a pretty bleak episode worldwide otherwise. Vivienne Parry: They are a small part, I know, of your organisation, Louise, but in some ways, those people with inherited cancers in their families are seeing the benefits of genomics on both sides, both in that earlier diagnosis, picking up right from the very beginning, and of course in the promise of these new treatments. Louise Fish: Yeah, absolutely, and you're right, it's a small part of our remit. We do have some organisations in our membership who specifically support people with rare inherited cancers, and we work very closely with an organisation called Cancer 52, who also represent organisations with rare cancers. I'll just give them a quick shoutout in case anyone listening is not aware of them and their amazing work. But you're right, I think there are a couple of things going on that are really exciting in the cancer space. It's that ability to better understand why some people are likely to inherit cancers, how that pattern works within families, and to support those families and help them understand like the risk that they have, and to make informed decisions about their own treatment and care in the future. And also about whether they want to have children, and if they do want to have children, kind of how they want to approach that to try and reduce the risk of passing on that heritability. So, that's a really important part for everybody. I think there's also potential to develop new treatments, which is absolutely amazing and really exciting, and it is really exciting to hear about the potential for cancer vaccines. The other area where I think people living with inherited cancers are interested to find out more is what impact it might have on better understanding which treatments will work for which people. And we know, for example, that there are some cancer treatments that only work for one in four people with that particular kind of cancer, but it's been really hard to understand why that's the case. And I think the potential for genomics to identify which people could benefit from a particular cancer treatment would have two huge benefits. A, cancer treatments, many of them are really horrible, you know. They're horrible things to go through, and if you had a better confidence that a particular treatment was going to work for you because of your genetic makeup, that would make you a lot more confident about deciding to try that treatment, and taking on board the side effects of the treatment and how it's going to impact on you. That would also obviously massively impact on the cost effectiveness of that treatment. At the moment, we might give it to four people and only one of them would benefit, but you're paying for the cost of giving it to all four people. If you could identify in advance which people were more likely to benefit then you'd give it to fewer people, they'd be more likely to benefit, and the cost would come down. So, I think that there is real potential in this field of genetics and genomics to help in all kinds of ways that people living with these conditions are really excited to see and explore. Vivienne Parry: So Matt there, it's not of course simply about identifying, you know, what the cancer is like and its genomic makeup, but actually it's that wider field of pharmacogenomics, which is a big feature of the programme at the Festival of Genomics this year. And we're very much involved in that, aren't we? Matt Brown: Yeah, we are. So, pharmacogenomics is one of those areas where genomics is about to make a big difference in clinical practice. What we're hoping to get to is the point where we have people who are not yet treated with a medication actually already have the genetic profiling done, so that when they go to a general practitioner or a physician and be prescribed a medication, the data will already be there to say what the appropriate dose should be, and whether they're at risk of getting adverse reactions to those medications, so we could avoid them or use alternate medications. So, that sort of pre-emptive pharmacogenomics is just over the horizon, and if we can achieve that, we're going to significantly improve patient care and reduce the risk of adverse drug reactions, which are a major cause of morbidity and hospital admissions not just in the UK but worldwide. Vivienne Parry: So Matt, perfect segue into our next question, which was, you've already identified one area which you think is going to be big in the next few years. You're both absolutely in the centre of the genomics ecosystem. What do you think we're going to be seeing at next year's Festival of Genomics? What do you think is going to be the big thing that's coming up on the inside rail? Matt Brown: So look, I'd like to say what I think's going to be in next year and what I think's going to be in ten years. Next year, I think the big things are going to be advances in AI and genomic analytics. That's really ramping up fast, and I think we're going to see it in clinical implementation a lot more next year. I think the cancer therapy vaccines are going to be really big next year, as are nucleic acid therapies. Multiomics for rare disease diagnosis and cancer personalised medicine, I think is also ramping up very fast. In ten years' time, the two areas that we've not discussed so far where I think genomics is going to make a big difference are going to be in infectious diseases and in pathology services. In infectious diseases, genomics I think has a fair chance of replacing to a large extent culture based practice, or serology based diagnosis of infectious diseases, which will be done by sequencing instead. And that will be a massive change to the practice there, because you'll be able to rapidly work out, even if people have been treated with antibiotics already, what the infections are and what the likely treatment responses are going to be. Louise Fish: So from my perspective, next year what I hope to see is people getting just as excited about the differences that some of the technology we hear about this year are actually making when they're being applied in clinical practice. So I think from my perspective, it's all about that move from being excited about the science to seeing people just as excited about the difference that science is actually making when it's benefiting people living with rare conditions and their families through clinics across the UK and the NHS. Next year, I'd like to hear that excitement when people are talking about how it's actually affecting real lives. In ten years' time, I hope we'll be talking about the massive difference that some of the amazing techniques we've heard about here this year have made to the lives of people living with genetic and rare conditions. So, you know, in ten years' time, I hope that some of the treatments and the opportunities and the tests we hear about today, we can see how they've affected the natural history of the condition across ten years of lives, and that we can really see that people are living their lives to the full as a result of the fantastic technological breakthroughs that we're hearing about today. Vivienne Parry: Fantastic. It's been great to talk to you both, and it has been a fantastic festival. Vivienne Parry: So, thank you to you again, and also thank you to Frontline Genomics, who organised the Festival of Genomics, because it really has been a wonderful, wonderful event. And if you're interested in things genomic, you can subscribe to the G Word on your favourite podcast app, and if you're new to our podcast, and we always welcome our new listeners, do check out our back catalogue. You'll find it's really extensive. There's a wonderful set of genomic listening available to you, in which even spatial transcriptomics gets explained. I've been your host, Vivienne Parry. This podcast was edited by Mark Kendrick at Ventoux Digital, and produced by Naimah Callachand, and it's very good to have had you with us. Bye for now, and hope to see you at the Festival of Genomics next year.

Aging-US
IL-17 Promotes IL-18 Production in Osteoarthritis Synovial Fibroblasts Via…

Aging-US

Play Episode Listen Later Feb 13, 2024 4:19


BUFFALO, NY- February 13, 2024 – A new #research paper was #published in Aging (listed by MEDLINE/PubMed as "Aging (Albany NY)" and "Aging-US" by Web of Science) Volume 16, Issue 2, entitled, “IL-17 promotes IL-18 production via the MEK/ERK/miR-4492 axis in osteoarthritis synovial fibroblasts.” The concept of osteoarthritis (OA) as a low-grade inflammatory joint disorder has been widely accepted. Many inflammatory mediators are implicated in the pathogenesis of OA. Interleukin (IL)-18 is a pleiotropic cytokine with versatile cellular functions that are pathogenetically important in immune responses, as well as autoimmune, inflammatory, and infectious diseases. IL-17, a proinflammatory cytokine mainly secreted by Th17 cells, is upregulated in OA patients. However, the role of IL-17 in OA progression is unclear. In this new study, researchers Kun-Tsan Lee, Chih-Yang Lin, Shan-Chi Liu, Xiu-Yuan He, Chun-Hao Tsai, Chih-Yuan Ko, Yuan-Hsin Tsai, Chia-Chia Chao, Po-Chun Chen, and Chih-Hsin Tang from National Chung-Hsing University, Taichung Veterans General Hospital, Shin-Kong Wu Ho-Su Memorial Hospital, Mackay Medical College, China Medical University, Show-Chwan Memorial Hospital, Fu-Jen Catholic University, National Taiwan Normal University, Asia University, and China Medical University Hsinchu Hospital used synovial tissues collected from healthy donors and OA patients to detect the expression level of IL-18 by immunohistochemistry stain. “Elucidation of the molecular mechanisms and main factors involved in OA pathogenesis may help with the development of novel therapeutic targets that relieve OA pain or prevent the disease from progressing.” The OA synovial fibroblasts (OASFs) were incubated with recombinant IL-17 and subjected to Western blot, qPCR, and ELISA to examine IL-18 expression level. The chemical inhibitors and siRNAs which targeted signal pathways were used to investigate signal pathways involved in IL-17-induced IL-18 expression. The microRNAs which participated IL-18 expression were surveyed with online databases miRWalk and miRDB, followed by validation with qPCR. This study revealed significantly higher levels of IL-18 expression in synovial tissue from OA patients compared with healthy controls, as well as increased IL-18 expression in OASFs from rats with severe OA. In vitro findings indicated that IL-17 dose-dependently promoted IL-18 production in OASFs. Molecular investigations revealed that the MEK/ERK/miR-4492 axis stimulated IL-18 production when OASFs were treated with IL-17. “This study provides novel insights into the role of IL-17 in the pathogenesis of OA, which may help to inform OA treatment in the future.” DOI - https://doi.org/10.18632/aging.205462 Corresponding authors - Po-Chun Chen - pcchen@ntnu.edu.tw, and Chih-Hsin Tang - chtang@mail.cmu.edu.tw Subscribe for free publication alerts from Aging - https://www.aging-us.com/subscribe-to-toc-alerts About Aging-US Launched in 2009, Aging-US publishes papers of general interest and biological significance in all fields of aging research and age-related diseases, including cancer—and now, with a special focus on COVID-19 vulnerability as an age-dependent syndrome. Topics in Aging-US go beyond traditional gerontology, including, but not limited to, cellular and molecular biology, human age-related diseases, pathology in model organisms, signal transduction pathways (e.g., p53, sirtuins, and PI-3K/AKT/mTOR, among others), and approaches to modulating these signaling pathways. Please visit our website at https://www.Aging-US.com​​ and connect with us: Facebook - https://www.facebook.com/AgingUS/ X - https://twitter.com/AgingJrnl Instagram - https://www.instagram.com/agingjrnl/ YouTube - https://www.youtube.com/@AgingJournal LinkedIn - https://www.linkedin.com/company/aging/ Pinterest - https://www.pinterest.com/AgingUS/ Spotify - https://open.spotify.com/show/1X4HQQgegjReaf6Mozn6Mc Media Contact 18009220957 MEDIA@IMPACTJOURNALS.COM

Oncotarget
Differential Silencing of STAT3 Isoforms Leads to Changes in STAT3 Activation

Oncotarget

Play Episode Listen Later Apr 26, 2023 3:34


A new research paper was published in Oncotarget's Volume 14 on April 24, 2023, entitled, “Differential silencing of STAT3 isoforms leads to changes in STAT3 activation.” Signal transducer and activator of transcription 3 (STAT3) is a transcription factor involved in multiple fundamental biological processes and a key player in cancer development and progression. STAT3 is activated upon tyrosine phosphorylation and is constitutively active in various malignancies; therefore, the expression of phospho-STAT3 (pSTAT3) has been recognized as a predictor of poor survival. STAT3 encodes two alternatively-spliced STAT3 isoforms: the full-length STAT3α isoform and the truncated STAT3β isoform. These isoforms have been suggested as the reason for the occasionally observed opposing roles of STAT3 in cancer: an oncogene, on one hand, and a tumor suppressor on the other. In this new study, researchers Inbal Shamir, Ilan Tsarfaty, Gidi Paret, and Yael Nevo-Caspi from Sheba Medical Center and Tel Aviv University investigated the roles of STAT3α and STAT3β in aggressive breast cancer. They manipulated endogenous STAT3 isoform expression and measured outcomes to mimic physiological changes more accurately. “In this study we examined the roles of STAT3 isoforms using specific siRNAs that target either STAT3α or STAT3β. We used the MDA-MB-231 cell line which represents an aggressive and mortal subtype of breast cancer, in which STAT3 is overexpressed and constitutively activated [14].” The team separately silenced each isoform in the MDA-MB-231 cell line and found that they affect each other's activation, impacting cell viability, cytokine expression, and migration. Their results show that each of the isoforms affects the activation (i.e., phosphorylation) of the other isoform and leads to changes in the outcome of the cells. They conclude that both STAT3α and STAT3β play a crucial role in the function of STAT3. Distinguishing between the two isoforms and their active forms is crucial for STAT3-related cancer diagnosis and therapy. “Referring to STAT3 as a single protein can lead to wrong conclusions, as they have different functions. Current STAT3 inhibitors target both isoforms, but this approach should be revised for better patient care. We present an endogenous mechanism that can shift the balance in a favorable direction, and we suggest developing treatments that mimic this mechanism could lead to new avenues for cancer therapy.” DOI: https://doi.org/10.18632/oncotarget.28412 Correspondence to - Yael Nevo-Caspi - yael.caspi@sheba.health.gov.il Keywords - STAT3: Signal transducer and activator of transcription 3, ER: endoplasmic reticulum, TAD: transactivation domain, SH2: Src homology 2, RQ: Relative quantitative Sign up for free Altmetric alerts about this article - https://oncotarget.altmetric.com/details/email_updates?id=10.18632%2Foncotarget.28412 Subscribe for free publication alerts from Oncotarget - https://www.oncotarget.com/subscribe/ About Oncotarget Oncotarget is a primarily oncology-focused, peer-reviewed, open access journal. Papers are published continuously within yearly volumes in their final and complete form, and then quickly released to Pubmed. On September 15, 2022, Oncotarget was accepted again for indexing by MEDLINE. Oncotarget is now indexed by Medline/PubMed and PMC/PubMed. To learn more about Oncotarget, please visit https://www.oncotarget.com and connect with us: SoundCloud - https://soundcloud.com/oncotarget Facebook - https://www.facebook.com/Oncotarget/ Twitter - https://twitter.com/oncotarget Instagram - https://www.instagram.com/oncotargetjrnl/ YouTube - https://www.youtube.com/@OncotargetJournal LinkedIn - https://www.linkedin.com/company/oncotarget Pinterest - https://www.pinterest.com/oncotarget/ Reddit - https://www.reddit.com/user/Oncotarget/ Media Contact MEDIA@IMPACTJOURNALS.COM 18009220957

SHOCKWAVES SKULLSESSIONS
TSWS | The Plane Truth Guy Returns and Spars With Mike!

SHOCKWAVES SKULLSESSIONS

Play Episode Listen Later Jan 26, 2023 131:28


On this edition of THE SETH WILLIAMS SHOW w/Mike Cheselka, Tony Musachio is live from Sirnas in Bedford to talk about their great food and the great history of the restaurant. The Flat Earth Guy joins the show to explain the biblical side of the flat earth as well as the scientific side. Things get pretty heated between the flat earther and Cheselka and Seth has to step in more than once to cool things off. Decide for yourself what you believe. Be sure to catch all the episodes, get your shirts and much more at http://www.thesethwilliamsshow.com. --- Send in a voice message: https://anchor.fm/cmspn/message

PaperPlayer biorxiv cell biology
A mechanism of melanogenesis mediated by E-cadherin downregulation and its involvement in solar lentigines

PaperPlayer biorxiv cell biology

Play Episode Listen Later Jan 10, 2023


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.09.523359v1?rss=1 Authors: Inoue, D., Narita, T., Ishikawa, K., Maeno, K., Motoyama, A., Ono, T., Aoki, H., Shibata, T. Abstract: Background: Intensive studies have revealed pleiotropic melanocytic factors for age spot formation. In particular, dysfunctional keratinocyte differentiation is thought to be an upstream cause of age spot formation. Although keratinocyte differentiation is mediated by a cell-cell contact factor, E-cadherin, its involvement in age spots remains unknown. To find the origin of age spots and an integrated solution, we focused on E-cadherin. Methods: Immunofluorescent staining with cutaneous tissues and cultured cells was performed. Keratinocytes treated with siRNAs were cocultured with melanocytes. With the supernatants of the keratinocyte culture, secretion factors were identified using proteomic analysis. For the activity of melanogenesis and the ingredient screening, a quantitative PCR was performed. For the behavioral analysis of melanocytes, time-lapse imaging of melanocytes was done by confocal laser scanning microscopy. Results: In age spots, E-cadherin expression in the epidermis was downregulated, suggesting that E-cadherin is implicated in age spot formation. E-cadherin knockdown (E-cad-KD) keratinocytes not only promoted the secretion of melanocytic/inflammatory factors, but also increased melanogenesis by upregulating the expression of melanogenesis factors. Furthermore, live imaging showed E-cadherin downregulation detained melanocyte dynamics and accelerated melanin-uptake. Finally, we identified Rosa multiflora fruit extract as a solution for upregulating E-cadherin in keratinocytes. Conclusion: Our findings showed that E-cadherin downregulation triggers various downstream melanocytic processes such as secretion of melanocytic factors and melanogenesis. Additionally, we showed that Rosa multiflora fruit extract upregulates E-cadherin expression in keratinocytes. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Ask EASL
EASL Studio Podcast: JHEP Live: Antisense oligonucleotides vs. siRNAs in the treatment of chronic hepatitis B: Who will be the winner, if at all?

Ask EASL

Play Episode Listen Later Nov 3, 2022 36:15


In this JHEP Live the faculty discuss the use of antisense oligonucleotides and siRNAs in the treatment of chronic hepatitis B infections.FacultyProf. Joerg Petersen (Moderator)Prof. Maria Buti (Faculty)Prof. Man-Fung Yuen (Faculty)All EASL Studio Podcasts are available on EASL Campus.

CCO Infectious Disease Podcast
Defining and Striving for HBV Cure: What's in the Pipeline

CCO Infectious Disease Podcast

Play Episode Listen Later Jun 30, 2022 14:37


In this episode,  Carla S. Coffin, MD, MSc, shares her thoughts on the different investigational approaches under evaluation for their potential to achieve HBV cure, including entry inhibitors, capsid inhibitors, siRNAs, immune modulators, TLR agonists, therapeutic vaccines, and checkpoint inhibitors.Presenter:Carla S. Coffin, MD, MScProfessor of MedicineDivision of Gastroenterology and HepatologyDepartment of MedicineUniversity of CalgaryMedical Director of Calgary Liver UnitDivision of Gastroenterology and HepatologyDepartment of MedicineFoothills Medical CentreCalgary, Alberta, CanadaContent based on an online CME program supported by independent educational grants from AbbVie and Gilead Sciences, Inc. and developed in collaboration with the American Liver Foundation. Link to full program:https://bit.ly/3OGHvOv

Aging-US
New Drug Combinations Inhibit Stress Proteins

Aging-US

Play Episode Listen Later Aug 20, 2021 6:10


Researchers from Virginia Commonwealth University, Translational Genomics Research Institute, and the Banner Alzheimer's Institute took part in a research study experimenting with combinations of therapeutic agents which they believe may improve neurodegenerative disorders. In 2021, their paper was published in Aging's Volume 13, Issue 13, and entitled, “Inhibition of heat shock proteins increases autophagosome formation, and reduces the expression of APP, Tau, SOD1 G93A and TDP-43.” “In this paper we examined using isogenic colon cancer cells [with] several existing drugs that function by increasing autophagy and degrading misfolded proteins.” “Aberrant expression of chaperone proteins is found in many human pathologies including cancer, in virology and in AD, ALS and HC.” In this study, researchers tested drugs that have been used preclinically and clinically in several anticancer studies. The drugs used were: AR12, an antiviral chaperone ATPase inhibitor; Neratinib, a tyrosine kinase inhibitor; a combination of AR12 and Neratinib; Fingolimod, an immunosuppressive sphingosine l-phosphate receptor modulator; MMF, monomethyl fumarate; and a combination of Fingolimod and MMF. The cells they tested these drug combinations on in vitro included Vero cells (African Green Monkey kidney cells), isogenic HCT116 colon cancer cells (genetically manipulated colon cancer cells), and GBM6 cells (glioblastoma cancer stem cells). They also used plasmids, antibodies, and siRNAs. Researchers acknowledged that the use of non-neuronal cells may be a limitation of this study. “Our present studies were performed in non-neuronal cells and as a caveat, it is possible that our data in HCT116 and Vero cells will not be reflective of the same processes in neuronal cells.” Despite this caveat, results from their research were promising. Some combinations of these drugs were capable of knocking down many disease specific proteins that form toxic aggregates inside cells and in extracellular environments via autophagy. Full blog - https://www.impactjournals.com/journals/blog/aging/trending-with-impact-new-drug-combinations-inhibit-stress-proteins/ Sign up for free Altmetric alerts about this article - https://oncotarget.altmetric.com/details/email_updates?id=10.18632%2Foncotarget.203297 DOI - https://doi.org/10.18632/aging.203297 Full text - https://www.aging-us.com/article/203297/text Correspondence to: Paul Dent email: paul.dent@vcuhealth.org Keywords: Alzheimer's, chaperone, GRP78, autophagy, neratinib About Aging-US Launched in 2009, Aging-US publishes papers of general interest and biological significance in all fields of aging research and age-related diseases, including cancer—and now, with a special focus on COVID-19 vulnerability as an age-dependent syndrome. Topics in Aging-US go beyond traditional gerontology, including, but not limited to, cellular and molecular biology, human age-related diseases, pathology in model organisms, signal transduction pathways (e.g., p53, sirtuins, and PI-3K/AKT/mTOR, among others), and approaches to modulating these signaling pathways. Please visit our website at http://www.Aging-US.com​​ or connect with us on: Twitter - https://twitter.com/AgingJrnl Facebook - https://www.facebook.com/AgingUS/ SoundCloud - https://soundcloud.com/aging-us​ YouTube - https://www.youtube.com/agingus​ LinkedIn - https://www.linkedin.com/company/aging​ Aging-US is published by Impact Journals, LLC please visit http://www.ImpactJournals.com​​ or connect with @ImpactJrnls Media Contact 18009220957 MEDIA@IMPACTJOURNALS.COM

PaperPlayer biorxiv bioinformatics
A small interfering RNA (siRNA) database for SARS-CoV-2

PaperPlayer biorxiv bioinformatics

Play Episode Listen Later Oct 1, 2020


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.30.321596v1?rss=1 Authors: Medeiros, I. G., Khayat, A. S., Stransky, B., dos Santos, S. E. B., Assumpcao, P. P., de Souza, J. E. S. Abstract: Coronavirus disease 2019 (COVID-19) rapidly transformed into a global pandemic, for which a demand for developing antivirals capable of targeting the SARS-CoV-2 RNA genome and blocking the activity of its genes has emerged. In this work, we propose a database of SARS-CoV-2 targets for siRNA approaches, aiming to speed the design process by providing a broad set of possible targets and siRNA sequences. Beyond target sequences, it also displays more than 170 features, including thermodynamic information, base context, target genes and alignment information of sequences against the human genome, and diverse SARS-CoV-2 strains, to assess whether siRNAs targets bind or not off-target sequences. This dataset is available as a set of four tables in a single spreadsheet file, each table corresponding to sequences of 18, 19, 20, and 21 nucleotides length, respectively, aiming to meet the diversity of technology and expertise among labs around the world concerning siRNAs design of varied sizes, more specifically between 18 and 21nt length. We hope that this database helps to speed the development of new target antivirals for SARS-CoV-2, contributing to more rapid and effective responses to the COVID-19 pandemic. Copy rights belong to original authors. Visit the link for more info

PaperPlayer biorxiv bioinformatics
In Silico Design of siRNAs Targeting Existing and Future Respiratory Viruses with VirusSi

PaperPlayer biorxiv bioinformatics

Play Episode Listen Later Aug 14, 2020


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.13.250076v1?rss=1 Authors: Zhang, D., Lu, J. Abstract: The COVID-19 pandemic has exposed global inadequacies in therapeutic options against both the COVID-19-causing SARS-CoV-2 virus and other newly emerged respiratory viruses. In this study, we present the VirusSi computational pipeline, which facilitates the rational design of siRNAs to target existing and future respiratory viruses. Mode A of VirusSi designs siRNAs against an existing virus, incorporating considerations on siRNA properties, off-target effects, viral RNA structure and viral mutations. It designs multiple siRNAs out of which the top candidate targets >99% of SARS-CoV-2 strains, and the combination of the top four siRNAs is predicted to target all SARS-CoV-2 strains. Additionally, we develop Greedy Algorithm with Redundancy (GAR) and Similarity-weighted Greedy Algorithm with Redundancy (SGAR) to support the Mode B of VirusSi, which pre-designs siRNAs against future emerging viruses based on existing viral sequences. Time-simulations using known coronavirus genomes as early as 10 years prior to the COVID-19 outbreak show that at least three SARS-CoV-2-targeting siRNAs are among the top 30 pre-designed siRNAs. Before-the-outbreak pre-design is also possible against the MERS-CoV virus and the 2009-H1N1 swine flu virus. Our data support the feasibility of pre-designing anti-viral siRNA therapeutics prior to viral outbreaks. We propose the development of a collection of pre-designed, safety-tested, and off-the-shelf siRNAs that could accelerate responses toward future viral diseases. Copy rights belong to original authors. Visit the link for more info

PaperPlayer biorxiv neuroscience
CRISPRCas9-based silencing of the ATXN1 gene in Spinocerebellar ataxia type 1 (SCA1) fibroblasts

PaperPlayer biorxiv neuroscience

Play Episode Listen Later Jul 4, 2020


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.04.187559v1?rss=1 Authors: Salvatori, F., Pappadà, M., Sicurella, M., Buratto, M., Simioni, V., Tugnoli, V., Marconi, P. Abstract: Spinocerebellar Ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by a gain-of-function protein with toxic activities, containing an expanded polyQ tract in the coding region. Actually, there are no treatments available to delay the onset, stop or slow down the progression of this pathology. Many approaches developed over the years involve the use of siRNAs and antisense oligonucleotides (ASOs). Here we develop and validate a CRISPR/Cas9 therapeutic strategy in fibroblasts isolated from SCA1 patients. We started from the screening of 10 different sgRNAs able to recognize regions upstream and downstream the CAG repeats, in exon 8 of ATXN1 gene. The two most promising sgRNAs, G3 and G8, whose efficiency was evaluated with an in vitro system, significantly downregulated the ATXN 1 protein expression. This downregulation was due to the introduction of indels mutations into the ATXN1 gene. Notably, with an RNA-seq analysis, we demonstrated minimal off-target effects of our sgRNAs. These preliminary results support CRISPR/Cas9 as a promising approach for treated polyQ-expanded diseases. Copy rights belong to original authors. Visit the link for more info

PaperPlayer biorxiv neuroscience
Microglial phagocytosis dysfunction is related to local neuronal activity in a genetic model of epilepsy

PaperPlayer biorxiv neuroscience

Play Episode Listen Later May 7, 2020


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.06.075903v1?rss=1 Authors: Sierra-Torre, V., Plaza-Zabala, A., Bonifazi, P., Abiega, O., Diaz-Aparicio, I., Tegelberg, S., Lehesjoki, A.-E., Valero, J., Sierra, A. Abstract: Microglial phagocytosis of apoptotic cells is an essential component of the brain regenerative response in neurodegenerative diseases. Phagocytosis is very efficient in physiological conditions, as well as during apoptotic challenge induced by excitotoxicity or inflammation, but is impaired in mouse and human mesial temporal lobe epilepsy (MTLE). Here we extend our studies to a genetic model of progressive myoclonus epilepsy type 1 (EPM1) in mice lacking cystatin B (CSTB), an inhibitor of cysteine proteases involved in lysosomal proteolysis. We first demonstrated that microglial phagocytosis was impaired in the hippocampus in Cstb knock-out (KO) mice when seizures arise and hippocampal atrophy begins, at 1 month of age. To test if this blockage was related to the lack of Cstb in microglia, we used an in vitro model of phagocytosis and siRNAs to acutely reduce Cstb expression but we found no significant effect in the phagocytosis of apoptotic cells. We then tested whether seizures were involved in the phagocytosis impairment, similar to MTLE, and analyzed Cstb KO mice before seizures begin, at postnatal day 14. Here, phagocytosis impairment was restricted to the granule neuron layer but not to the subgranular zone, where there are no active neurons. Furthermore, we observed apoptotic cells (both phagocytosed and not phagocytosed) in Cstb deficient mice at close proximity to active, cFos+ neurons and used mathematical modeling to demonstrate that the physical relationship between apoptotic cells and cFos+ neurons was specific for Cstb KO mice. These results suggest a complex crosstalk between apoptosis, phagocytosis and neuronal activity, hinting that local neuronal activity could be related to phagocytosis dysfunction in Cstb KO mice. Overall, this data suggest that phagocytosis impairment is an early feature of hippocampal damage in epilepsy and opens novel therapeutic approaches for epileptic patients based on targeting microglial phagocytosis. Copy rights belong to original authors. Visit the link for more info

Move the human story forward! ™ ideaXme
RNA - Essential For All Human Life: Therapies

Move the human story forward! ™ ideaXme

Play Episode Listen Later Nov 13, 2019 42:50


Ira Pastor, ideaXme exponential health ambassador and founder of Bioquark, interview Dr. Lorna Harries, Professor of Molecular Genetics at University of Exeter Medical School. Ira Pastor Comments Today as we continue our discussions on ideaXme pertaining to the biological hierarchy of life, we are going to journey into what I refer to as the "metabolic architecture of the cell", and all of the fascinating dynamics that surround our genomes and allow the information encoded within to impact the on-going physiological states of our health, disease, and aging processes. In doing so we will segue into a discussion around a category of biologic entities, broadly known as Ribonucleic acids (or RNA). RNA RNA is a polymeric molecule essential in various biological roles including coding, decoding, regulation and expression of genes. Cellular organisms use one of the primary forms of RNA, messenger RNA (mRNA) to convey genetic information from our DNA to direct synthesis of specific proteins integral in appropriate gene expression across our cell lineages. RNA silencing or "RNA interference" (RNAi) is the process by which protein production from a gene is turned off. The term "RNA therapeutics" means either the use of one of the other forms of regulatory RNAs (e.g., siRNAs, microRNA) directly as a therapeutic agent and/or the modulation of RNA-based processes with more traditional drugs (e.g. small molecules). Because RNA is central to all biological processes, there are numerous potential avenues for addressing human disorders at the RNA level including many chronic degenerative diseases, infections, and even aging processes themselves. Our guest today, who is an expert in this unique domain of biology and is going to take us further into the topic, is Professor Lorna Harries, Professor of Molecular Genetics, University of Exeter Medical School. Dr. Lorna Harries Dr. Harries has a PhD in Molecular Genetics from University College London, and set up the "RNA-Mediated Mechanisms of Disease Group" at the University of Exeter Medical School in 2006. Her team has a special focus on how RNA biology can influence both normal and disease states, from large-scale "omics" approaches, down to detailed assessment of specific mechanisms in specific genes. Dr. Harries leads the group's investigation into how and why we age, and the reason age is a major risk factor in diseases like Type-2 Diabetes. Her goal is to use the information the group uncovers to develop a new generation of anti-degenerative drugs. As many age-related diseases have common roots, causes and mechanisms, which arise from the failure of a few basic health-maintenance mechanisms that decline in efficiency as we age, the Harries lab feels by focusing and by targeting them, they will eventually be able to target multiple age-related diseases at once. Dr. Harries has written over 90 peer-reviewed articles and was awarded the Diabetes UK RD Lawrence Prize Lectureship in 2011. She is coordinator of the annual UEMS "Men in White" school outreach with Dr. John Chilton, an event that brings in year 9 students from schools stretching from South Devon to North Somerset and gives them hands-on experience of work in a research laboratory. Dr. Harries is also is a STEMnet ambassador as well as an Exeter Catalyst Champion for Public Engagement. On this show we will hear from Dr. Harries: About her background, how she became interested in science, molecular biology, and how she finds herself at the forefront of RNA biology and therapeutics. The history of RNA therapeutics and why according to her recent Nature article "It's Time for Scientists to Shout About RNA Therapies." An overview of RNA splicing, the spliceosome, splicing factors, and their respective roles in human ageing. Her work in RNA regulation of human cellular senescence. Her work in RNA regulation of Type-2 Diabetes. Her future visions for her work. Dr. Lorna Harries will be speaking at the following upcoming conferences: 6th Annual Middle East Diabetes Conference Dubai 29-30 Jan 2020 Splicing 2020 meeting Capirica 12-16 July 2020  Allergan Science of Aging meeting Monaco 30th March - 1st April 2020 (dates provisional!) Longevity Leaders London April 21-22 2020  

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 05/06
Toward unraveling biogenesis of Dicer-independent priRNAs and siRNAs in Schizosaccharomyces pombe

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 05/06

Play Episode Listen Later Jun 15, 2015


RNA interference (RNAi) is a highly conserved process of gene silencing in which Argonaute family proteins are guided by small RNA molecules to complementary targets. In the fission yeast Schizosaccharomyces pombe, RNAi is required for heterochromatin formation at centromeres. Although it seems counterintuitive, pericentromeric heterochromatin in fission yeast is transcribed. The transcripts are processed by RNAi machinery, which is in turn guided back to the pericentromeric repeats by sequence complementarity of the Argonaute-bound small interfering RNA (siRNA) and the nascent transcript. This generates a positive-feedback loop of siRNA amplification that recruits factors required for the assembly of heterochromatin. Previously, it was suggested that a fission yeast class of Dicer-independent small RNAs called primal small RNAs (priRNAs) initiates the positive-feedback loop of siRNA generation and heterochromatin assembly. However, the biogenesis of priRNAs as well as of Dicer-independent small RNAs from other organisms was not well understood. The results presented here identify Triman, a novel 3’-5’ exonuclease that is involved in the final step of biogenesis of both priRNAs and siRNAs in fission yeast. It was observed that Argonaute binds longer priRNA and siRNA precursors from the total RNA fraction. This is followed by the recruitment of Triman to trim 3’ ends of Argonaute-bound small RNAs to the mature size. The final trimming of priRNAs and siRNAs is required for de novo heterochromatin formation at centromeres and the mating-type locus as well as for the maintenance of facultative heterochromatin islands. Furthermore, it was shown that in cells lacking Rrp6, a nuclease subunit of the exosome, RNAi targets various genes across the yeast genome. This demonstrated that the exosome protects the genome against aberrant RNAi. Spurious RNAi targeting in rrp6∆ cells at majority of loci occurs via accumulation of antisense transcripts that are processed into priRNAs in a Triman-dependent manner. These results suggest that Argonaute association with cellular degradation products which are processed into priRNAs might serve as a surveillance mechanism to guard the genome against invading genomic elements (Marasovic et al. 2013).

Rna Structure and Function 2014
J. E. Dahlberg -Controlling miRNAs and siRNAs during embryonic development- RNA Structure and Function 2014

Rna Structure and Function 2014

Play Episode Listen Later Apr 16, 2014 33:29


James E. Dahlberg, University of Wisconsin, Madison, WI - USA speaks on "Controlling miRNAs and siRNAs during embryonic development - RNA Structure and Function 2014". This seminar has been recorded at ICTP Trieste by ICGEB Trieste

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 14/19
Zelluläre Modulatoren der Ektodomänenspaltung von APP

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 14/19

Play Episode Listen Later Jul 31, 2012


The processing of APP occurs in two alternative ways: upon release of the ectodomain by α-secretase, the neuroprotective APPsα-fragment is produced. But if APP is cleaved by the β-secretase the Aβ-peptide can be produced. To be able to influence the production of Aβ-peptides, it is essential to understand how it is decided if cleavage occurs by α- or β-secretase. At present little is known about the control of the alternate processing. Until now, the molecular mechanisms and especially the responsible cellular modulators are not understood in detail or not yet identified. To get a better understanding of cellular regulatory processes and to identify novel cellular modulators of APP ectodomain shedding, the present work chose two approaches: on the one hand cellular mechanisms of TMEM59-mediated inhibition ectodomain shedding of APP were investigated. On the other hand a genome-wide RNAi screening in Drosophila cells was performed in order to identify novel cellular modulators of APP ectodomain shedding in human cells. TMEM59 was identified as a novel modulator of APP ectodomain shedding in a cDNA expression screening in the lab (Neumann et al., 2006; Schobel et al., 2008; Schobel et al., 2006). TMEM59 is a Golgi protein that inhibits on the one hand processing and maturation of APP and on the other hand Golgi glycosylation reactions (Fischer, 2008). My own work could verify these effects of TMEM59 and its homolog TMEM59L on processing and maturation of APP. In particular, it was shown that these effects are not only true for transiently expressed APP but also for endogenous levels of APP. In detailed immunofluorescence studies it was shown that TMEM59 colocalizes with different markers of the Golgi subcompartments and that therefore TMEM59 is present throughout the whole Golgi apparatus. This finding points to a more general modulation of Golgi glycosylation reactions by TMEM59. To test if TMEM59-dependet modulation of Golgi glycosylation reactions also affects APP secretases ADAM10 and BACE1, which are also glycosylated proteins, the activities of these proteases were investigated. It was shown that proteolytic activities were not changed, ruling out that impairment of secretase activities by TMEM59 could cause the observed inhibition of APP processing. But interestingly, studies of intracellular APP transport could show that TMEM59 caused retention of APP in the Golgi apparatus and blockage of transport towards the cell surface and into endosomal compartments. Since APP is cleaved by α-secretase at the plasma membrane and by β-secretase in endosomes it is likely that a TMEM59-dependent APP transport block causes the observed inhibition of APP ectodomain shedding. For further validation of TMEM59 and its homolog TMEM59L as modulators of APP ectodomain shedding, a double knockdown study was performed. In this approach effects on APP ectodomain shedding could also be established, affirming TMEM59 and its homolog TMEM59L as modulators of APP ectodomain shedding with novel cellular mechanisms. In order to identify novel cellular modulators of APP ectodomain shedding a genome wide RNAi screening in Drosophila cells was performed and candidate genes were investigated in human cells in present work. Initially a suitable Drosophila reporter cell line expressing a reporter construct of APP ectodomain shedding (HRP-APP) was established. Other constructs were used to monitor general secretion (GLuc) and transfection efficiency (FLuc). Using Kuzbanian, the α-secretase in Drosophila (Sapir et al., 2005), as a positive control guaranteed that transfection of cDNAs into Drosophila cells did not interfere with uptake of dsRNAs or efficiency of RNAi and that the reporter construct HRP-APP is normally produced and processed in reporter cells. After successful establishment of the reporter cell line the genome wide RNAi was performed in two steps: a primary screening revealed approx. 300 candidate genes out of which 43 could be confirmed in a secondary screening to be modulators of APP ectodomain shedding. The RNAi screening was verified by the several-fold appearance of Kuzbanian among the top modulators. For further investigation of the top candidates human ortholog genes were identified. The 30 human candidate genes were investigated in RNAi studies in human SH-SY5Y cells. In these cells, APP is processed by α-secretase ADAM10 as well as by β-secretase BACE1. Therefore effects on both shedding products (APPsα and APPsβ) were investigated upon depletion of candidate genes using siRNAs. It is known that siRNAs produce a high rate of off target effects, to this end a robust validation strategy was developed. Candidate genes were first depleted with two different siRNA pools and their effects on APP shedding were compared. Afterwards the remaining 12 candidate genes were depleted using single siRNA sequences and the effects were compared to those of the siRNA pool. Only when a reproduction of effects was obtained in a next step correlation of knockdown and phenotype were assessed. Using these steps of validation 5 candidate genes could be verified as modulators of APP shedding in human cells: next to genes coding for a histone protein (HIST1H4C), a ribosomal protein (RPL36AL), a protein of the minor spliceosom (ZMAT5), an unknown gene (METTL16) and the gene VPS24 („vacuolar protein sorting-associated protein 24“), coding for a protein of intracellular protein transport, were identified. VPS24 was chosen for further validation by a pathway analysis. VPS24 belongs to the ESCRT machinery („endosomal sorting complex required for transport“) and therefore participates in endosomal-lysosomal protein transport. In further RNAi studies other members of the ESCRT machinery were depleted in human cells and effects on APP shedding were compared to VPS24 depletion. For most of the ESCRT members a consistent reduction in APPsβ production could be observed. To engross these results VPS24 was depleted by using an alternative RNAi system. With this stable knockdown approach, the knockdown phenotype could be confirmed. This stepwise validation strategy for candidate genes of the initial Drosophila RNAi screening verified VPS24 as a modulator of APP ectodomain shedding in human cells.

app apps candidate fischer neumann drosophila rnai sirna golgi cdna gluc zellul ddc:600 adam10 sirnas cdnas fluc bace1 sh sy5y escrt modulatoren
Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 04/06
Targeted RNAi and pDNA based therapy for gastrointestinal tumors

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 04/06

Play Episode Listen Later Mar 1, 2012


In this work, we were able to take advantage of a deregulated wnt signaling pathway – a condition which is found in most gastrointestinal cancers, in particular in colorectal carcinomas. In order to restrict reporter gene expression to the desired cell type, we utilized the β-catenin dependent CTP4-promoter to restrict the expression of Firefly Luciferase and enhanced green fluorescent fusion protein (EGFPLuc) to cell lines with deregulated wnt signaling including SW480, LS174T, HepG2, Coga2 and Coga12. Stable cell lines containing this CTP4-driven EGFPLuc construct were established with the help of a lentiviral vector to monitor wnt activity by transgene expression. With these stably transduced cell lines, we performed a therapeutic target screen via siRNA-mediated knock-down of a number of potentially therapeutic targets within the wnt pathway – osteoprotegerin (OPG), Traf2 and Nck-interacting kinase (TNIK), SRY-related HMG-box (Sox2), protease-activated receptor 1 (PAR-1), β-catenin and transcription factor 4 (TCF4). The in vitro screening system was utilized as a prevalidation tool for therapeutically relevant targets. The degree of interference of our novel targets was determined and the search for a suitable siRNA target in colorectal cancer cells was narrowed down to β-catenin, PAR-1 and TNIK. As proof of principle the siRNA-mediated knock down of β-catenin was verified on mRNA and protein level in LS174T cells. After the initial read-out of various cell lines with different siRNAs has been established via the reduction of Luciferase expression levels, the biological effect of these targets were validated. For this purpose colony formation and cell motility/invasion assays were conducted for all relevant target cell lines. Furthermore in the in vitro experiments, the tumor-selectivtiy of the CTP4-promoter was employed in the delivery of the cytotoxic protein diphteria toxin A (DTA) in colorectal cancer target cells. Data evaluation of all in vitro assays pointed at reduced levels of proliferation, invasive behavior and aggressiveness, which yielded three candidates (PAR-1, TNIK and β-catenin) considered as viable for a treatment attempt in vivo. In the in vivo experiments, systemic delivery of siRNA against β-catenin, sticky siRNA targeting PAR-1 and plasmid DNA encoding for CTP4 controlled DTA were evaluated in a disseminated liver metastasis model of LS174T colorectal cancer. Specific knock-downs of β-catenin and PAR-1 were achieved which was confirmed via mRNA analysis. As for CTP4-DTA pDNA delivery the overall tumor load of the liver was reduced without any significant systemic toxicity, indicating specific DTA expression in tumor tissue. Also knock down of PAR1 using sticky siRNA significantly reduced tumor growth. All in all, the therapeutic effect of PAR-1 and β-catenin knock-down could be verified in various in vitro assays analyzing invasive behavior and anchorage independent growth and ultimately also in vivo. The tumor-specific expression of DTA pDNA could also be confirmed in vitro and was further investigated in an orthotopic liver dissemination model in NMRI nude mice.

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 13/19
Downregulation of endogenous TRAIL and its effect on the human cancer cell line KELLY

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 13/19

Play Episode Listen Later Nov 24, 2011


Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to exert an unexpected pro-survival, pro-proliferative and pro-invasive effect on a subset of human cancer cell lines. Recent clinical studies report that increased expression of endogenous TRAIL is associated with decreased disease-specific survival in renal cell carcinoma and cholangiocarcinoma which are resistant to TRAIL induced apoptosis. The present work investigated the role of endogenous TRAIL as an intrinsic growth factor in apoptosis-resistant human cancer cells. Several cell lines derived from solid human tumors were studied, among them the neuroblastoma cell line KELLY, a cancer cell line resistant to TRAIL-induced apoptosis. First, to investigate whether TRAIL-knockdown could inhibit cell growth, the use of small interfering RNAs (siRNA) for endogenous TRAIL was established and a successful knockdown was verified on both mRNA and protein level. Second, the functional impact of the knockdown of endogenous TRAIL was investigated by measuring cell growth and cell death after transfection: Interestingly, the human neuroblastoma cell line KELLY unexpectedly showed markedly reduced cell growth upon knockdown of endogenous TRAIL. Furthermore, knockdown of TRAIL induced cell death in KELLY cells, which was dependent on caspase-signaling and rescued by the addition of soluble TRAIL. Thus, endogenous TRAIL functions as an intrinsic survival and growth factor in the neuroblastoma cell line KELLY. The present work provided first evidence that the expression of endogenous TRAIL can be specifically downregulated through siRNA knockdown to inhibit survival and growth of cancer cells in-vitro, which are resistant to TRAIL induced apoptosis. The present data strongly supports the potential of endogenous TRAIL to function as a novel therapeutic target in cancer therapy. In the light of the emerging clinical use of siRNAs for cancer therapy, targeting TRAIL by RNA interference may provide a valuable treatment approach for patients with cancers resistant to TRAIL induced apoptosis and high expression levels of endogenous TRAIL.

Rna Structure and Function
J. E. Dahlberg - MicroRNAs, siRNAS and RNAi in early frog development

Rna Structure and Function

Play Episode Listen Later Apr 18, 2011 33:56


James E. Dahlberg, University of Wisconsin, Madison, USA speaks on "MicroRNAs, siRNAS and RNAi in early frog development". This seminar has been recorded at ICTP Trieste by ICGEB Trieste

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 03/06
Functional characterisation of microRNA-containing Argonaute protein complexes

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 03/06

Play Episode Listen Later Jul 13, 2009


microRNAs (miRNAs) are small non-coding RNAs of 21-24 nt in size, which are endogenously expressed in higher eukaryotes and play important roles in processes such as tissue development and stress response and in several diseases including cancers. In mammals, miRNAs guide proteins of the Argonaute family (Ago proteins) to partially complementary sequences typically located in the 3’-untranslated regions (3’-UTRs) of specific target mRNAs, leading to translational repression or mRNA degradation. To gain further insight into the function of human miRNAs, we analyzed the protein as well as the RNA composition of miRNA-Ago protein complexes in molecular detail. To identify novel Ago-interacting proteins, we isolated Ago complexes and investigated them by mass spectrometry and co-immunoprecipitation experiments. We found that trinucleotide repeat-containing 6B (TNRC6B), Moloney leukemia virus 10 (MOV10), RNA binding motif protein 4 (RBM4) and Importin 8 (Imp8) interact with human Ago proteins. Moreover, using RNA interference and EGFP and dual luciferase reporter assays, we demonstrated that these factors are required for miRNA function, indicating that we have identified new components of the miRNA pathway. Intriguingly, depletion of Imp8 does not affect the levels of mature miRNAs or the interaction of miRNAs with Ago proteins, but is required for efficient association of Ago-miRNA complexes with their target mRNAs. Thus, Imp8 is the first factor acting at the level of target mRNA binding, establishing a novel layer of regulation for the miRNA pathway. Imp8 is an Importin-β-like protein, which has previously been implicated in nuclear import of substrate proteins. In line with these results, we demonstrated that a detectable fraction of Ago2 localizes to the nucleus of human cells. Moreover, knockdown of Imp8 by RNAi reduces the nuclear signal of Ago2, suggesting that Imp8 affects the nuclear localization of Ago2. Therefore, our data suggest that Imp8 has a dual function both in the cytoplasmic miRNA pathway and in nuclear transport of Ago proteins. To identify small RNAs, which associate with human Ago proteins, we isolated, cloned and sequenced small RNAs bound to Ago1 and Ago2 complexes. In addition to known miRNAs, we found several small RNAs, which derive from small nucleolar RNAs (snoRNAs). We therefore investigated the function of one particular small RNA, which is derived from the snoRNA ACA45 and showed that it functions like a miRNA. Interestingly, this small RNA is processed by the miRNA maturation factor Dicer, but does not require the microprocessor complex that is essential for processing of primary miRNA transcripts. Thus, we have identified a novel biogenesis pathway of a new class of small RNAs that can function like miRNAs. To experimentally identify mRNAs that are stably associated with miRNA-Ago protein complexes, we isolated and analyzed Ago1 and Ago2-bound mRNAs by cloning and sequencing and by microarray hybridization techniques. Using dual luciferase reporter assays, we demonstrated that many Ago-associated mRNAs are indeed miRNA targets. Therefore, we have developed a method allowing for the identification of miRNA target mRNAs from cell lines or tissues of interest independently of computational predictions. In a project that was independent of our studies on Ago protein complexes, we investigated structural and functional requirements for the activity of small interfering RNAs (siRNAs). siRNAs are small double-stranded RNAs of appr. 21 nt in size, which trigger the sequence-specific endonucleolytic degradation of perfectly complementary target transcripts upon binding to Ago2. However, both single strands of a siRNA duplex can potentially have unwanted “off-target effects” by repressing partially complementary target mRNAs through binding to their 3’-UTRs. We therefore developed a method to selectively inhibit the activity of the siRNA strand that is dispensable for target silencing (“passenger strand”) through chemical modification of its 5’-end. This method could be a useful tool for the design of highly specific siRNAs. Taken together, we have analyzed the composition of Ago-miRNA protein complexes by a variety of methods and identified novel protein factors of the miRNA pathway, a novel class of small RNAs as well as a panel of previously unknown miRNA target mRNAs. The techniques for the purification and the analysis of Ago complexes that were developed in this study will provide useful tools for future analyses of miRNA pathway factors, small RNAs and miRNA target mRNAs from any tissue or cell line of interest.

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 02/06
The 37kDa/67kDa laminin receptor as a therapeutic target in prion diseases: potency of antisense LRP RNA, siRNAs specific for LRP mRNA and a LRP decoy mutant

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 02/06

Play Episode Listen Later Apr 6, 2006


Prion diseases are a group of rare, fatal neurodegenerative diseases, also known as transmissible spongiform encephalopathies (TSEs), that affect both animals and humans and include bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep, chronic wasting disease in deer and elk and Creutzfeldt-Jakob disease (CJD) in humans. TSEs are usually rapidly progressive and clinical symptoms comprise dementia and loss of movement coordination. A common hallmark of TSEs is the accumulation of an abnormal isoform (PrPSc) of the host-encoded prion protein (PrPc) in the brains of affected animals and humans. PrPc is a highly conserved cell surface sialoglycoprotein that is expressed in several cell types, mainly neuronal cells, but its normal physiological function is still not known. However, PrPc is elementary for the acquisition and the replication of prion diseases. Several inhibitors of the PrPSc formation have been reported, but none of them showed great potency in an in vivo application. Thus, the identification of the 37kDa/67kDa laminin receptor (LRP/LR) as the cell surface receptor for prions opened a new direction for the development of a TSE therapy. Currently, no treatment to slow down or stop the disease process in humans with any form of CJD is established. However, several strategies have been investigated to find an anti-prion treatment including development of a vaccination therapy and screening for potent chemical compounds. In scrapie-infected neuronal cells, which represent a widely used and well characterized in vitro model for transmissible spongiform encephalopathies, the accumulation of PrPSc has been prevented by transfection of (i) antisense LRP RNA, (ii) small interfering RNAs targeting the LRP mRNA and (iii) incubation with the polyclonal anti-LRP antibody W3. Furthermore, the knock down of surface LRP/LR resulted in a reduction of the cellular PrP levels, suggesting an interference with the PrP internalization process. Thus, LRP/LR is required for the PrPSc propagation in vitro and involved in the PrPc metabolism.Due to the existence of several LR genes, a major step to investigate the role of the 37kDa/67kDa laminin receptor in scrapie pathogenesis in vivo is the generation of transgenic mice exhibiting a lower level of LRP/LR. Hemizygous transgenic mice that express LRP/LR antisense RNA under the control of the neuron-specific enolase (NSE) promoter were generated and showed a reduced LRP/LR protein level in the cerebellum and the hippocampus. Intracerebral inoculation of these transgenic mice with the scrapie agent will show, whether the accumulation of pathogenic PrPSc in the brain is delayed or prevented due to a reduced LRP/LR level. A further therapeutic anti-prion approach is given by LRP/LR deletion mutants that can be secreted to the cell culture medium and might act as decoys. Previously, it has been demonstrated that a transmembrane deletion mutant is able to prevent PrPc binding and internalization. In vitro studies using an N-terminally truncated LRP mutant, representing the extracellular domain of LRP/LR (LRP102-295::FLAG), revealed a reduced binding of (i) recombinant cellular PrP to mouse neuroblastoma cells, (ii) infectious moPrP 27-30 to BHK21 cells and (iii) interfered with the PrPSc propagation in chronically scrapie-infected mouse neuroblastoma cells. Furthermore, a cell free binding assay demonstrated the direct binding of the LRP102-295::FLAG mutant to both PrPc and PrPSc. These results together with the finding that that endogenous LRP levels remain unaffected by the expression of the mutant indicate that the secreted LRP102-295::FLAG mutant may act in a trans-dominant negative manner as a decoy by trapping PrP molecules. To investigate the therapeutic potential of the LRP102-295::FLAG decoy mutant in vivo transgenic mice were generated ectopically expressing LRP102-295::FLAG in the brain. Animals showed no phenotype and transgene expression was detected in cortical and cerebellar brain regions. An intracerebral prion inoculation of these mice will prove whether the expression of the LRP102-295::FLAG mutant can impair the PrPSc accumulation in the brain and can thus, act as a alternative therapeutic tool in prion diseases. The recent finding that experimental introduction of RNA can be used to interfere with the function of an endogenous gene (RNA interference) provided another tool for the development of gene-specific therapeutics. In order to evaluate a gene transfer therapeutic TSE strategy, human immunodeficiency virus (HIV)-derived vectors that express short hairpin RNA (shRNA) directed against the LRP mRNA were used. Following integration of LRP-shRNA-expressing lentiviral vectors into the genome of neuronal cells efficient LRP/LR downregulation was observed. In scrapie infected neuronal cells, downregulation of the LRP gene expression resulted in a diminishment of PrPSc propagation, providing a further therapeutic strategy in the development of a TSE treatment.

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 02/06
Single chain antibodies against the 37 kDa/67 kDa laminin receptor as tools for prion diseases therapy

Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 02/06

Play Episode Listen Later Jan 24, 2006


Prions are unconventional pathogens that cause transmissible spongiform encephalopathies (TSEs). According to the "protein only" hypothesis, prions consist of an infectious protein that is capable of converting a normal host protein termed PrPc into a protease resistant form termed PrPSc. PrPSc is poorly degraded by the host and accumulates in the CNS. Normal biological functions of PrPc and mechanisms involved in neurodegeneration remain obscure. During the past two decades, considerable efforts have been made to elucidate prion diseases and in particular to identify PrP interactors for a better understanding in prion biology. A major break-through was the identification of the 37 kDa laminin receptor (LRP), which represents the precursor of the human 67 kDa high-affinity laminin receptor (LR), as the cell surface receptor for the cellular prion protein. We investigated the role of LRP/LR in the propagation of PrPSc in chronically infected cells by different approaches. Three strategies resulted in downregulation or blocking of LRP and prevented PrPSc accumulation in different scrapie infected neuronal cell lines (i) transfection with an antisense LRP RNA expression plasmid (ii) transfection with small interfering (siRNAs) specific for the LRP mRNA and (iii) incubation with the polyclonal anti-LRP antibody, W3. We observed that the treatment with W3 abolished PrPSc deposition and reduced PrPc levels after one week of incubation. PrPSc did not reappear in cells being cultured for 14 additional days without therapeutic antibody treatment. Taken together, these results indicate that LRP is not only required for PrPc metabolism under non-pathological conditions but also has a pivotal role in prion propagation in a cell culture model. LRP/LR appears then to be a promising potential target for the development of therapeutics for the treatment of prion disease. Due to these encouraging cell culture data, we decided to select single chain antibodies (scFv) encompassing a suitable format for therapy. ScFvs are composed of variable parts of heavy and light chains of an immunoglobulin that are connected by a peptidic linker. The antibodies were screened on recombinant GST::LRP employing a phage display strategy. Two scFvs termed N3 and S18 were screened and selected by ELISA. Both antibodies were further characterized by western blotting and FACS analysis: both N3 and S18 specifically recognized mouseLRP and humanLRP overexpressed in mammalian cells under denaturating conditions (western blot) and under native conditions at the cell surface (FACS). Epitope mapping revealed that as expected both scFvs are directed against the extracellular part of LRP: S18 and N3 recognized amino acid residues 225-233 and 273-278, respectively. The ability of N3 and S18 to interfere with LRP/PrP interaction was tested by pull-down assays. In contrast to the control scFv C9 directed against the pre-S1 coat-protein of hepatitis B virus, both anti-LRP scFvs were able to block the specific LRP/PrP binding. In order to investigate a potential curing effect of scFv S18 in vivo, this scFv was tested in a scrapie mouse model by passive immunization. The application of S18 by intra-peritoneal injection was able to reduce PrPSc deposition in the spleen in comparison to mice injected with PBS or C9. However the survival times of S18 treated animals was not increased. Anti-LRP scFv S18 seems to contribute to block prion propagation in the periphery but it is likely that this effect was not enough strong to have an impact on the CNS invasion. Thus, we hypothesized that a strategy targeting directly the brain should be more effective. In this context, an approach based on the expression of single chain antibodies as secretory molecules in the brain via an adeno-associated virus (AAV) vector was initiated. To assure secretion of the scFv expressed in mammalian cells, a signal sequence was fused to the scFvs. Tranfection experiments demonstrated that neuronal cells were able to express and secrete high quantities of both scFvs. Furthermore, the generated scFvs were still functional as shown by western blotting. To find the appropriate AAV serotype for scFv expression, neuronal cells were transduced with varying serotypes carrying a GFP. AAV serotype 2 was chosen due to (i) its good transduction performance in two neuronal cell lines and (ii) the possibility of its purification by affinity chromatography. The sequences encoding for the scFvs N3, S18 and C9 have been cloned in an AAV-based vector. The AAV system was also able to drive high expression of scFvs into the supernatant by transfection or transduction. rAAV-scFv particles were produced and purifed for further stereotaxic injections into mice. Although the investigation of this therapeutic strategy is still in progress in a murine scrapie model, we already proved that a single injection of rAAV led to the expression of scFvs into the brain of mice 30 days post injection. This study represents the first gene therapeutic approach for the treatment of prion diseases.