Podcasts about nkx2

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.31.551374v1?rss=1 Authors: Ishioka, M., Nihashi, Y., Sunagawa, Y., Umezawa, K., Shimosato, T., Kagami, H., Morimoto, T., Takaya, T. Abstract: An 18-base myogenetic oligodeoxynucleotide (myoDN), iSN04, acts an anti-nucleolin aptamer and induces myogenic differentiation of skeletal muscle myoblasts. This study investigated the effect of iSN04 on murine embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). In the undifferentiated state, iSN04 inhibited the proliferation of ESCs and iPSCs but did not affect the expression of pluripotent markers. In the differentiating condition, iSN04 treatment of ESCs/iPSCs from day 5 onward dramatically induced the differentiation into Nkx2-5+ beating cardiomyocytes with upregulation of Gata4, Isl1, and Nkx2-5, whereas iSN04 treatment from earlier stages completely inhibited cardiomyogenesis. RNA sequencing revealed that iSN04 treatment from day 5 onward contributes to the generation of cardiac progenitors by modulating the Wnt signaling pathway. Immunostaining showed that iSN04 suppressed the cytoplasmic translocation of nucleolin and restricted it to the nucleoli. These results demonstrate that nucleolin inhibition by iSN04 facilitates the terminal differentiation of cardiac mesoderm into cardiomyocytes, but interferes with the differentiation of early mesoderm into the cardiac lineage. This is the first report on the generation of cardiomyocytes from pluripotent stem cells using a DNA aptamer. Since iSN04 did not induce hypertrophic responses in primary-cultured cardiomyocytes, iSN04 would be useful and safe for the regenerative therapy of heart failure using stem cell-derived cardiomyocytes. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.27.538511v1?rss=1 Authors: Chamberland, S., Grant, G., Machold, R. P., Nebet, E. R., Tian, G., Hanani, M., Kullander, K., Tsien, R. W. Abstract: Hippocampal somatostatin-expressing (Sst) GABAergic interneurons (INs) exhibit considerable anatomical and functional heterogeneity. Recent single cell transcriptome analyses have provided a comprehensive Sst-IN subtype census, a plausible molecular ground truth of neuronal identity whose links to specific functionality remain incomplete. Here, we designed an approach to identify and access subpopulations of Sst-INs based on transcriptomic features. Four mouse models based on single or combinatorial Cre- and Flp- expression differentiated functionally distinct subpopulations of CA1 hippocampal Sst-INs that largely tiled the morpho-functional parameter space of the Sst-INs superfamily. Notably, the Sst;;Tac1 intersection revealed a population of bistratified INs that preferentially synapsed onto fast-spiking interneurons (FS-INs) and were both necessary and sufficient to interrupt their firing. In contrast, the Ndnf;;Nkx2-1 intersection identified a population of oriens lacunosum-moleculare (OLM) INs that predominantly targeted CA1 pyramidal neurons, avoiding FS-INs. Overall, our results provide a framework to translate neuronal transcriptomic identity into discrete functional subtypes that capture the diverse specializations of hippocampal Sst-INs. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.19.537540v1?rss=1 Authors: Khan, S. T., Ahuja, N., Taib, S., Vohra, S., Cleaver, O., Nunes, S. S. Abstract: The pancreatic islet vasculature displays tissue-specific physiological and functional adaptations that support rapid glucose sensing and insulin response by beta-cells. To uncover the transcriptomic basis of this specialization, we performed a meta-analysis of multi-organ single cell RNA sequencing atlases employing a unique strategy to avoid transcriptomic contamination. We identified biologically relevant genes involved in sphingosine-1-phosphate-mediated insulin secretion (PLPP1, RDX, CDC42), islet basement membrane formation (SPARC, COL15A1), endothelial cell (EC) permeability (PLVAP, EHD4), membrane transporters (CD320, SLCO2A1) and developmental transcription factors (NKX2-3, AHR). These were validated in silico in an independent dataset. We further established the first integrated transcriptomic atlas of human pancreatic ECs and described two unique capillary subpopulations: exocrine and endocrine pancreas ECs. We validated the spatial localization of key markers using RNAscope and immunofluorescence staining on mouse pancreatic tissue cross-sections. Our findings provide novel insights into pancreatic EC heterogeneity and islet EC function with potential implications in therapeutic strategies. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.18.533275v1?rss=1 Authors: DeSpenza, T., Kiziltug, E., Allington, G., Barson, D., O'Connor, D., Robert, S. M., Mekbib, K. Y., Nanda, P., Greenberg, A., Singh, A., Duy, P. Q., Mandino, F., Zhao, S., Lynn, A., Reeves, B. C., Marlier, A., Getz, S. A., Nelson-Williams, C., Shimelis, H., Zhang, J., Walsh, L. K., Wang, W., Smith, H., OuYang, A., Deniz, E., Lake, E., Jin, S. C., Luikart, B. W., Kahle, K. T. Abstract: Expansion of the cerebrospinal fluid (CSF)-filled cerebral ventricles (ventriculomegaly) is the quintessential feature of congenital hydrocephalus (CH) but also seen in autism spectrum disorder (ASD) and several neuropsychiatric diseases. PTEN is frequently mutated in ASD; here, we show PTEN is a bona fide risk gene for the development of ventriculomegaly, including neurosurgically-treated CH. Pten-mutant hydrocephalus is associated with aqueductal stenosis due to the hyperproliferation of periventricular Nkx2.1+ neural precursors (NPCs) and CSF hypersecretion from inflammation-dependent choroid plexus hyperplasia. The hydrocephalic Pten-mutant cortex exhibits ASD-like network dysfunction due to impaired activity of Nkx2.1+ NPC-derived inhibitory interneurons. Raptor deletion or post-natal Everolimus corrects ventriculomegaly, rescues cortical deficits, and increases survival by antagonizing mTORC1-dependent Nkx2.1+ cell pathology. These results implicate a dual impact of PTEN mutation on CSF dynamics and cortical networks via the dysregulation of NPCs and their interneuron descendants. These data identify a non-surgical treatment target for hydrocephalus and have implications for other developmental brain disorders. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.04.510883v1?rss=1 Authors: White, A. K., Drake, K. D., Porczak, A. E., Tirado-Mansilla, G., Lee, M. F., Hyatt, K. C., Chow, C., DeQuattro, T., Mickelsen, L. E., Sciolino, N. R., Jackson, A. C., Kanadia, R. N. Abstract: While gene regulatory networks underlying hypothalamic development are being characterized, minor intron splicing remains unexplored. Here, we used Nkx2.1-Cre to ablate Rnu11, encoding the minor spliceosome-specific U11 snRNA, in the progenitors of the ventral diencephalon (VD), to study minor intron splicing in hypothalamic development and control of energy balance in mice. Loss of U11 resulted in aberrant minor intron splicing, mitotic stalling, apoptosis, and altered neurogenesis. Mutant mice exhibited gross dysgenesis of hypothalamic architecture, while single-cell RNA sequencing (scRNAseq) revealed aberrant composition of neuronal subtypes implicated in feeding and energy balance. Mutant weanlings failed to thrive, followed by rapid weight gain, resulting in obesity. Assessment of energy imbalance and pair-feeding demonstrated that hyperphagia in adult mutants initiates weight gain, and is compounded by metabolic dysfunction, ultimately resulting in obesity. Our findings suggest a key role of minor intron splicing in the developmental patterning of hypothalamic neuronal subtypes underlying energy balance. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

This month on Episode 38 of Discover CircRes, host Cynthia St. Hilaire highlights original research articles featured in the Jue 24th, July 8th and July 22nd issues of the journal. This episode also features an interview with the 2022 BCBS Outstanding Early Career Investigator Award finalists, Dr Hisayuki Hashimoto, Dr Matthew DeBerge and Dr Anja Karlstadt.   Article highlights:   Nguyen, et al. miR-223 in Atherosclerosis.   Choi, et al. Mechanism for Piezo1-Mediated Lymphatic Sprouting   Kamtchum-Tatuene, et al.  Plasma Interleukin-6 and High-Risk Carotid Plaques   Li, et al. 3-MST Modulates BCAA Catabolism in HFrEF   Cindy St. Hilaire:        Hi, and welcome to Discover CircRes, the podcast of the American Heart Association's journal, Circulation Research. I'm your host, Dr Cindy St. Hilaire, from the Vascular Medicine Institute at the University of Pittsburgh. And today I'm going to be highlighting articles from our June 24th, July 8th and July 22nd issues of Circulation Research. I'm also going to have a chat with the finalists for the 2022 BCBS Outstanding Early Career Investigator Award, Dr Hisayuki Hashimoto, Dr Matthew DeBerge and Dr Anja Karlstadt.   Cindy St. Hilaire:        The first article I want to share is from our June 24th issue and is titled, miR-223 Exerts Translational Control of Proatherogenic Genes in Macrophages. The first authors are My-Anh Nguyen and Huy-Dung Hoang, and the corresponding author is Katey Rayner and they're from the University of Ottawa. A combination of cholesterol accumulation in the blood vessels and subsequent chronic inflammation that's derived from this accumulation drive the progression of atherosclerosis. Unfortunately, current standard medications tackle just one of these factors, the cholesterol. And this might explain why many patients on such drugs still have vascular plaques. In considering treatments that work on both aspects of the disease, meaning lipid accumulation and inflammation, this group investigated the micro RNA 223 or miR-223, which is a small regulatory RNA that has been shown to suppress expression of genes involved in both cholesterol uptake and inflammatory pathways in both liver and immune cells.   Cindy St. Hilaire:        The team showed that mouse macrophages deficient in miR-223, exhibited increased expression of pro-inflammatory cytokines and reduced cholesterol efflux compared with control cells. Overexpression of miR-223 had the opposite effects. Furthermore, atherosclerosis prone mice, whose hematopoietic cells lacked miR-223, had worse atherosclerosis with larger plaques and higher levels of pro-inflammatory cytokines than to control animals with normal levels of miR-223. These findings highlight miR-223's dual prompt, antiatherogenic action, which could be leveraged for future therapies.   Cindy St. Hilaire:        The second article I want to share is from our July 8th issue of Circulation Research and is titled, Piezo1-Regulated Mechanotransduction Controls Flow-Activated Lymph Expansion. The first author is Dongwon Choi and the corresponding author is Young-Kwon Hong, and they're from UCLA.   As well as being super highways for immune cells, lymph vessels are drainage channels that help maintain fluid homeostasis in the tissues. This network of branching tubes grows as fluids begin to flow in the developing embryo. This fluid flow induces calcium influx into the lymphatic endothelial cells, which in turn promotes proliferation and migration of these cells, leading to the sprouting of lymph tubules. But how do LECs, the lymphatic endothelial cells, detect fluid flow in the first place? Piezo1 is a flow and mechanosensing protein known for its role in blood vessel development and certain mutations in Piezo1 cause abnormal lymphatic growth in humans.   Cindy St. Hilaire:        This script found that Piezo1 is expressed in the embryonic mouse LECs and that the suppression of Piezo1 inhibits both flow activated calcium entry via the channel ORAI1, as well as downstream target gene activation. Overexpression of Piezo1, by contrast, induced the target genes. The team went on to show that mice lacking either Piezo1 or ORAI1 had lymphatic sprouting defects and that pharmacological activation of Piezo1 in mice enhanced lymphogenesis and prevented edema after tail surgery. Together, the results confirmed Piezo1's role in flow dependent lymphatic growth and suggest it might be a target for treating lymphedema.   Cindy St. Hilaire:        The third article I want to share is also from our July 8th issue and is titled, Interleukin-6 Predicts Carotid Plaque Severity, Vulnerability and Progression. The first and corresponding author of this study is Joseph Kamtchum-Tatuene from University of Alberta.   Excessive plasma cholesterol and systemic inflammation are contributing factors in atherosclerosis. While traditional remedies have been aimed at lowering patient's lipid levels, drugs that tackle inflammation are now under investigation, including those that suppress Interleukin-6, which is an inflammatory cytokine implicated in the disease. Focusing on carotid artery disease, this group conducted a prospective study to determine whether IL-6 levels correlated with disease severity. 4,334 individuals were enrolled in the cardiovascular health study cohort. They had their blood drawn and ultrasounds taken at the start of the study and five years later. This group found IL-6 was robustly correlated with and predicted plaque severity independent of other cardiovascular risk factors. This study also determined that an IL-6 blood plasma level of 2.0 picograms/mls, identified individuals with the highest likelihood of plaque, vulnerability and progression. This threshold value could be used to select patients who might benefit from novel IL-6 lowering medications.   Cindy St. Hilaire:        The last article I want to share is from our July 22nd issue of Circulation Research and is titled, Mitochondrial H2S Regulates BCAA Catabolism in Heart Failure. The first author is Zhen Li, and the corresponding author is David Lefer from Louisiana State University. Hydrogen sulfide, or H2S, is a compound that exerts mitochondrial specific actions that include the preservation of oxidative phosphorylation, mitochondrial biogenesis and ATP synthesis, as well as inhibiting cell death. 3-mercaptopyruvate sulfurtransferase, or 3-MST, is a mitochondrial H2S producing enzyme, whose functions in cardiovascular disease are not fully understood.   Cindy St. Hilaire:        This group investigated the global effects of 3-MST deficiency in the setting of pressure overload induced heart failure. They found that 3-MST was significantly reduced in the myocardium of patients with heart failure, compared with non failing controls. 3-MST knockout mice exhibited increased accumulation of branch chain amino acids in the myocardium, which was associated with reduced myocardial respiration and ATP synthesis, exacerbated cardiac and vascular dysfunction, and worsened exercise performance, following transverse aortic constriction. Restoring myocardial branched-chain amino acid catabolism, or administration of a potent H2S donor, ameliorated the detrimental effects of 3-MST deficiency and heart failure with reduced injection fraction. These data suggest that 3-MST derived mitochondrial H2S, may play a regulatory role in branch chain amino acid catabolism, and mediate critical cardiovascular protection in heart failure.   Cindy St. Hilaire:        Today, I'm really excited to have our guests, who are the finalists for the BCVS Outstanding Early Career Investigator Awards. Welcome everyone.   Hisayuki Hashimoto:   Thank you.   Anja Karlstaedt:          Hi.   Hisayuki Hashimoto:   Hi.   Matthew DeBerge:      Hello. Thank you.   Cindy St. Hilaire:        So the finalists who are with me today are Dr Hisayuki Hashimoto from Keio University School of Medicine in Tokyo, Japan, Dr Matthew Deberge from Northwestern University in Chicago and Dr Anja Karlstaedt from Cedar Sinai Medical Center in LA. Thank you again. Congratulations. And I'm really excited to talk about your science.   Hisayuki Hashimoto:   Thank you. Yes. Thanks, first of all for this opportunity to join this really exciting group and to talk about myself and ourselves. I am Hisayuki Hashimoto, I'm from Tokyo, Japan. I actually learned my English... I went to an American school in a country called Zaire in Africa and also Paris, France because my father was a diplomat and I learned English there. After coming back to Japan, I went to medical school. During my first year of rotation, I was really interested in cardiology, so I decided to take a specialized course for cardiology. Then I got interested in basic science, so I took a PhD course, and that's what brought me to this cardiology cardiovascular research field.   Matthew DeBerge:      So I'm currently a research assistant professor at Northwestern University. I'm actually from the Chicagoland area, so I'm really excited to welcome you all to my hometown for the BCVS meeting.   Cindy St. Hilaire:        Oh, that's right. And AHA is also there too this year. So you'll see a lot of everybody.   Matthew DeBerge:      I guess I get the home field advantage, so to speak. So, I grew up here, I did my undergrad here, and then went out in the east coast, Dartmouth College in New Hampshire for my PhD training. And actually, I was a viral immunologist by training, so I did T cells. When I was looking for a postdoctoral position, I was looking for a little bit of something different and came across Dr Edward Thorpe's lab at Northwestern university, where the interest and the focus is macrophages in tissue repair after MI. So, got into the macrophages in the heart and have really enjoyed the studies here and have arisen as a research assistant professor now within the Thorpe lab. Now we're looking to transition my own independent trajectory. Kind of now looking beyond just the heart and focusing how cardiovascular disease affects other organs, including the brain. That's kind of where I'm starting to go now. Next is looking at the cardiovascular crosstalk with brain and how this influences neuroinflammation.   Anja Karlstaedt:          I am like Hisayuki, I'm also a medical doctor. I did my medical training and my PhD in Berlin at the Charité University Medicine in Berlin, which is a medical faculty from Humboldt University and Freie University. II got really interested in mathematical modeling of complex biological systems. And so I started doing my PhD around cardiac metabolism and that was a purely core and computationally based PhD. And while I was doing this, I got really hooked into metabolism. I wanted to do my own experiments to further advance the model, but also to study more in crosstalk cardiac metabolism. I joined Dr Heinrich Taegteyer lab at the University of Texas in the Texas Medical Center, and stayed there for a couple of years. And while I was discovering some of the very first interactions between leukemia cells and the heart, I decided I cannot stop. I cannot go back just after a year. I need to continue this project and need to get funding. And so after an AHA fellowship and NIHK99, I am now here at Cedars Sinai, an assistant professor in cardiology and also with a cross appointment at the cancer center and basically living the dream of doing translational research and working in cardio-oncology.   Cindy St. Hilaire:        Great. So, Dr Hashimoto, the title of your submission is, Cardiac Reprogramming Inducer ZNF281 is Indispensable for Heart Development by Interacting with Key Cardiac Transcriptional Factors. This is obviously focused on reprogramming, but why do we care about cardiac reprogramming and what exactly did you find about this inducer ZNF281?   Hisayuki Hashimoto:   Thank you for the question. So, I mean, as I said, I'm a cardiologist and I was always interested in working heart regeneration. At first, I was working with pluripotent stem cells derived cardiomyocyte, but then I changed my field during my postdoc into directly programming by making cardiomyocyte-like cells from fiberblast. But after working in that field, I kind of found that it was a very interesting field that we do artificially make a cardiomyocyte-like cell. But when I dissected the enhanced landscape, epigenetic analysis showed that there are very strong commonalities between cardiac reprogramming and heart development. So I thought that, hey, maybe we can use this as a tool to discover new networks of heart development. And the strength is that cardiac reprogramming in vitro assay hardly opens in vivo assay, so it's really time consuming. But using dark programming, we can save a lot of time and money to study the cardiac transitional networks. And we found this DNF281 from an unbiased screen, out of 1000 human open reading frames. And we found that this gene was a very strong cardiac reprogramming inducer, but there was no study reporting about any functioning heart development. We decided to study this gene in heart development, and we found out that it is an essential gene in heart development and we were kind of able to discover a new network in heart development.   Cindy St. Hilaire:        And you actually used, I think it was three different CRE drivers? Was that correct to study?   Hisayuki Hashimoto:   Ah, yes. Yeah.   Cindy St. Hilaire:        How did you pick those different drivers and what, I guess, cell population or progenitor cell population did those drivers target?   Hisayuki Hashimoto:   So I decided to use a mesodermal Cre-driver, which is a Mesp1Cre and a cardiac precursor Cre-driver, which is the Nkx2-5 Cre and the cardiomyocyte Cre, which is the Myh6-Cre. So three differentiation stages during heart development, and we found out that actually, DNF281 is an essential factor during mesodermal to cardiac precursor differentiation state. We're still trying to dig into the molecular mechanism, but at that stage, if the DNF281 is not there, we are not able to make up the heart.   Cindy St. Hilaire:        That is so interesting. Did you look at any of the strains that survived anyway? Did you look at any phenotypes that might present in adulthood? Is there anything where the various strains might have survived, but then there's a kind of longer-term disease implicating phenotype that's observed.   Hisayuki Hashimoto:   Well, thank you for the question. Actually, the mesodermal Cre-driver knocking out the DNF281 in that stage is embryonic lethal, and it does make different congenital heart disease. And they cannot survive until after embryonic day 14.5. The later stage Nkx2-5 Cre and Myh6-Cre, interestingly, they do survive after birth. And then in adult stage, I did also look into the tissues, but the heart is functioning normally. I haven't stressed them, but they develop and they're alive after one year. It looks like there's really no like phenotype at like the homeostatic status.   Cindy St. Hilaire:        Interesting. So it's kind of like, once they get over that developmental hump, they're okay.   Hisayuki Hashimoto:   Exactly. That might also give us an answer. What kind of network is important for cardiac reprogramming?   Cindy St. Hilaire:        So what are you going to do next?   Hisayuki Hashimoto:   Thank you. I'm actually trying to dig into the transitional network of what kind of cardiac transitional network the ZNF281 is interacting with, so that maybe I can find a new answer to any etiology of congenital heart disease, because even from a single gene, different mutation, different variants arise different phenotypes in congenital heart disease. Maybe if I find a new interaction with any key cardiac transitional factors, maybe I could find a new etiology of congenital heart disease phenotype.   Cindy St. Hilaire:        That would be wonderful. Well, best of luck with that. Congratulations on an excellent study. Hisayuki Hashimoto:   Thank you.   Cindy St. Hilaire:        Dr DeBerge, your study was titled, Unbiased Discovery of Allograft Inflammatory Factor-1 as a New and Critical Immuno Metabolic Regulatory Node During Cardiac Injury. Congrats on this very cool study. You were really kind of focused on macrophages in myocardial infarction. And macrophages, they're a Jeckel Hyde kind of cell, right? They're good. They're bad. They can be both, almost at the same time, sometimes it seems like. So why were you interested in macrophages particularly in myocardial infarction, and what did you discover about this allograft inflammatory factor-1, or AIF1 protein?   Matthew DeBerge:      Thank you. That's the great question. You really kind of alluded to why we're interested in macrophages in the heart after tissue repair. I mean, they really are the central mediators at both pro-inflammatory and anti-inflammatory responses after myocardial infarction. Decades of research before this have shown that inflammation has increased acutely after MI and has also increased in heart failure patients, which really has led to the development of clinical efforts to target inflammatory mediators after MI. Now, unfortunately, the results to target inflammation after MI, thus far, have been modest or disappointing, I guess, at worst, in the respect that broadly targeting macrophage function, again, hasn't achieved results. Again, because these cells have both pro and anti-inflammatory functions and targeting specific mediators has been somewhat effective, but really hasn't achieved the results we want to see.   Matthew DeBerge:      I think what we've learned is that the key, I guess, the targeting macrophage after MI, is really to target their specific function. And this led us to sort of pursue novel proteins that are mediating macrophage factor function after MI. To accomplish this, we similarly performed an unbiased screen collecting peri-infarct tissue from a patient that was undergoing heart transplantation for end stage heart failure and had suffered an MI years previously. And this led to the discovery of allograft inflammatory factor-1, or AIF1, specifically within cardiac macrophages compared to other cardiac cell clusters from our specimen. And following up with this with post-mortem specimens after acute MI to show that AIF1 was specifically increased in macrophages after MI and then subsequently then testing causality with both murine model of permanent inclusion MI, as well as in vitro studies using bone marrow drive macrophages to dig deeper mechanistically, we found that AIF1 was crucial in regulating inflammatory programing macrophages, which ultimately culminated in worse in cardiac repair after MI.   Cindy St. Hilaire:        That's really interesting. And I love how you start with the human and then figure out what the heck it's doing in the human. And one of the things you ended up doing in the mouse was knocking out this protein AIF1, specifically in macrophage cells or cells that make the macrophage lineage. But is this factor in other cells? I was reading, it can be intracellular, it can be secreted. Are there perhaps other things that are also going on outside of the macrophage?   Matthew DeBerge:      It's a great question. First, I guess in terms of specificity, within the hematopoietic compartment, previous studies, as well as publicly available databases, have shown that AIF1 is really predominantly expressed within macrophages. We were able to leverage bone marrow chimera mice to isolate this defect to the deficiency to macrophages. But you do bring up a great point that other studies have shown that AIF1 may be expressed in other radio-resistant cell populations. I mean, such as cardiomyocytes or other treatable cells within the heart. We can't completely rule out a role for AIF1 and other cell populations. I can tell you that we did do the whole body knockout complementary to our bone marrow hematopoetic deficient knockouts, and saw that deficiency of AIF1 within the whole animal, recapitulate the effects we saw within the AIF1 deficiency within hematopoietic department.   Matthew DeBerge:      It was encouraging to us that, again, the overall role of AIF1 is pro-inflammatory after MI.   Cindy St. Hilaire:        I mean, I know it's early days, but is there a hint of any translational potential of these findings or of this protein?   Matthew DeBerge:      Yeah, I think so. To answer your question, we were fortunate enough to be able to partner with Ionis that develops these anti-sensible nucleotides so that we could specifically target AIF1 after the acute phase during MI. We saw that utilizing these anti-sensible nucleotides to deplete AIF1, again, within the whole mouse, that we were able to reduce inflammation, reduce in heart size and preserve stock function. I think there really is, hopefully a therapeutic opportunity here. And again, with it being, perhaps macrophage specific is, even much more important as we think about targeting the specific function of these cells within the heart.   Cindy St. Hilaire:        Very cool stuff. Dr Karlstaedt, the title of your submission is, ATP Dependent Citrate Lyase Drives Metabolic Remodeling in the Heart During Cancer. So this I found was really interesting because you were talking about, the two major killers in the world, right? Cardiovascular disease and cancer, and you're just going to tackle both of them, which I love. So obviously this is built on a lot of prior observations about the effects of cancer on cardiac metabolic remodeling. Can you maybe just tell us a little bit about what is that link that was there and what was known before you started?   Anja Karlstaedt:          Yeah. Happy to take that question. I think it's a very important one and I'm not sure if I will have a comprehensive answer to this, because like I mentioned at the beginning, cardio-oncology is a very new field. And the reason why we are starting to be more aware of cancer patients and their specific cardiovascular problems is because the cancer field has done such a great job of developing all these new therapeutics. And we have far more options of treating patients with various different types of cancers in particular, also leukemias, but also solid tumors. And what has that led to is an understanding that patients survive the tumors, but then 10, 20 years later, are dying of cardiovascular diseases. Those are particular cardiomyopathies and congestive heart failure patients. What we are trying, or what my lab is trying to do, is understanding what is driving this remodeling. And is there a way that we can develop therapies that can basically, at the beginning of the therapy, protect the heart so that this remodeling does not happen, or it is not as severe.   Anja Karlstaedt:          Also, identifying patients that are at risk, because not every tumor is created equally and tumors are very heterogeneous, even within the same group. To get to your question, what we found is, in collaboration actually with a group at Baylor College of Medicine, Peggy Goodell's group, who is primarily working on myeloid malignancies, is that certain types of leukemias are associated with cardiomyopathies. And so when they were focusing on the understanding drivers of leukemia, they noticed that the hearts of these animals in their murine models are enlarged on and actually developing cardiomyopathies. And I joined this project just very early on during my postdoc, which was very fortunate and I feel very lucky of having met them. What my lab is now studying here at Cedars is how basically those physiological stress and mutations coming from the tumors are leading to metabolic dysregulation in the heart and then eventually disease.   Anja Karlstaedt:          And we really think that metabolism is at the center of those disease progressions and also, because it's at the center, it should be part of the solution. We can use it as a way to identify patients that are at risk, but also potentially develop new therapies. And what was really striking for us is that when we knock down ACLY that in a willdtype heart where the mouse doesn't have any tumor disease, ACLY actually is critically important for energy substrate metabolism, which seems counterintuitive, because it's far away from the mitochondria, it's not part of directly ADP provision. It's not part of the Kreb cycle. But what we found is that when we knock it out using a CRISPR-Cas9 model, it leads to cardiomyopathy and critically disrupts energy substrate metabolism. And that is not necessarily the case when the mouse has leukemia or has a colorectal cancer, which upregulated in the beginning, this enzyme expression. And so we have now developed models that show us that this could be potentially also therapeutic target to disrupt the adverse remodeling by the tumor.   Cindy St. Hilaire:        That is so interesting. So one of the things I was thinking about too is we know that, I mean, your study is showing that, the tumor itself is causing cardiac remodeling, but we also know therapies, right? Radiation, chemotherapy, probably some immune modulatory compounds. Those probably do similar, maybe not exactly similar, but they also cause, adverse cardiac remodeling. Do you have any insights as to what is same and what is different between tumor driven and therapy driven adverse remodeling?   Anja Karlstaedt:          So we do not know a lot yet. It's still an open question about all the different types of chemotherapeutics, how they are leading to cardio toxicities. But what we know, at least from the classic anti-cyclic treatments, is right now at the core, the knowledge is that this is primarily disrupting cardiac mitochondrial function. And through that again, impairing energy provision and the interaction, again, with the immune system is fairly unknown, but we know through studies from Kathryn Moore and some very interesting work by Rimson is that myocardial infarction itself can lead to an increase in risk for tumor progression. And what they have shown as independent of each other, is that the activation of the immune system in itself can lead to an acceleration of both diseases, both the cardiac remodeling, and then also the tumor disease. We don't fully understand which drivers are involved, but we do know that a lot of the cardiomyopathies on cardiotoxicities that are chemotherapeutically driven, all have also metabolic component.   Cindy St. Hilaire:        Nice. Thank you. When I prepare for these interviews, I obviously read the abstracts for the papers, but I found myself also Googling other things after I read each of your abstracts. It was a rabbit hole of science, which was really exciting.                               I now want to transition to kind of a career angle. You all are obviously quite successful, scientifically, at the bench, right? But now you are pivoting to a kind of completely opposite slash new job, right? That of, independent researcher. I would love to hear from each of you, if there was any interesting challenge that you kind of overcame that you grew from, or if there was any bit of advice that you wish you knew ahead of time or anything like that, that some of our trainee listeners and actually frankly, faculty who can pass that information onto their trainees, can benefit from.   Anja Karlstaedt:          I think the biggest challenge for me in transitioning was actually the pandemic. Because I don't know how it was for Hisa and Matt, but trying to establish a lab, but also applying for faculty position during a major global pandemic, is challenging is not quite something that I expected that would happen. And so I think saying that and looking more conceptually and philosophically at this as, you can prepare as much as you want, but then when life just kicks in and things happen, they do happen. And I think the best is to prepare as much as you can. And then simply go with the flow. Sometimes one of my mentors, Dave Nikon, mentioned that to me when I was applying for faculty positions, it's sometimes good to just go with the flow. And as a metabolism person, I absolutely agree. And there are some things that you can do as a junior investigator.   Anja Karlstaedt:          We need to have a good network. So just very important to have good mentors. I was blessed with have those mentors, Peggy Goodell's one of them, Heinrich Taegtmeyer was another. And now with this study that we are publishing, Jim Martin and Dave Nikon were incredible. Without them, this study wouldn't have been possible and I would not be here at Cedars.   Anja Karlstaedt:          You need to reach out to other people because those mentors have the experience. They have been through some of this before. Even if they have never had a major event, like COVID-19 in their life before, because none of us had before, they had other experiences and you can rely on them and they set you then up for overcoming these challenges. And the other thing I would say, is put yourself out there, go and talk to as many people as possible or set conferences, present a poster, not only talks. Don't be disappointed if you don't get a talk, posters are really great to build this network and find other people that you probably wouldn't have encountered and apply for funding. Just again, put yourself out there and try to get the funding for your research. Even if it's small foundations, it builds up over time and it is a good practice to then write those more competitive grants.     Cindy St. Hilaire:        Dr Hashimoto, would you like to go next?   Hisayuki Hashimoto:   Just my advice is that, could be like a culture of difference, but in east Asia, like in Japan, we were taught to, do not disturb people, don't interrupt people and help people. But I realized that I wasn't really good at asking for help. After I am still not like fully independent, but I do have my own group and I have to do grant writing. I still work at the bench and then have to teach grad students, doing everything myself. I just realized it's just impossible. I didn't have time. I need like 48 hours a day. Otherwise, you won't finish it. I just realized that I wasn't really good at asking for help. So my advice would be, don't hesitate to ask for help. It's not a shame. You can't do everything by just yourself. I think, even from the postdoc, even from grad school, I think, ask for help and then get used to that. And then of course, help others. And that is the way I think to probably not get overwhelmed and not stress yourself. Science should be something fun. And if you don't ask for help and if you don't help someone, I think you are losing the chance of getting some fun part from the science.   Cindy St. Hilaire:        That's great advice. I really like that, especially because I find at least, I started my lab seven years ago now. And I remember the first couple months/year, it was extremely hard to let go, right? Like I taught my new people how to do the primary cell culture we needed, but I was terrified of them doing it wrong or wasting money or making too many mistakes. But you realize, you got to learn to trust people. Like you said, you got to learn to ask for help. And sometimes that help is letting them do it. And you doing, you're being paid now to write grants and papers. That's a big brain, you're not paid to do the smaller things. That's really great advice. I like that. Thank you. Dr DeBerge, how about you?   Matthew DeBerge:      So I guess towards a bit of life advice, I think two obvious things is one, be kind, science is hard enough as it is. So I think we should try to lift each other up and not knock each other down. And along those lines as the others have alluded to as well, one of the mantras we sort of adapted on the lab, is a rising tide raises all ships, this idea that we can work together to elevate each other's science and really, again, collaborate.   Towards the career side of things I'll just touch on, because I guess one thing I'll add, there's more than one path, I guess, to achieving your goals. I've been fortunate enough to have an NIH post-doctoral fellowship and had an AHA career development award, but I'm not a K99 recipient. Oftentimes, I think this is the golden ticket to getting the faculty job, so I'm trying to, I guess, buck trend, I just submitted an RO1. So fingers crossed that leads to some opportunity.   Even beyond academia, I'm not certain how much everyone here is involved in science Twitter, it's really become a thing over the last couple years, but I think, kind of the elephant in the room is that academia, it's really hard on the trainees nowadays to have a living wage, to go through this. I mean, I'm really excited to see my, fellow finalists here are starting their own groups and stuff, but for many, that's not the reality for many, it's just not financially feasible. So I think, kind of keeping in mind that there's many, many alternative careers, whether it's industry, whether it's consulting, science writing, etcetera, going back to what Dr Hash says, find what you love and really pursue that with passion.   Cindy St. Hilaire:        I think it's something only, I don't know, five to 10% of people go into or rather stay in academia. And that means, 90 to 95% of our trainees, we need to prepare them for other opportunities, which I think is exciting, because it means it can expand our network for those of us in academia.   Anja Karlstaedt:          I think right now it's even worse because it's about 2% of old postdocs that are actually staying and becoming independent researchers, independent or tenure track or research track. And I think I second, as what Matt said, because I play cello. I do music as a hobby and people always ask me if I'm a musician. And at the beginning I felt like, no, of course not. I'm not like Yoyo Ma. I'm just playing, it's a hobby. And then I, that got me thinking. I was like, no, of course you are because there's so many different types. And what we need to understand is that scientists, like you are always a scientist. It doesn't matter if you are working at Pfizer or if you are working at a small undergrad institution and you're teaching those next generation scientists, you are still scientist and we all need those different types of scientists because otherwise, if everybody is just a soloist, you are never going to listen to symphony. You need those different people and what we need to normalize beyond having those different career paths, is also that people are staying in academia and becoming those really incredible resources for the institutions and labs, quite frankly, of being able to retain those technologies and techniques within an institution. And I think that's something to also look forward to, that even if you're not the PI necessarily, you're the one who is driving those projects. And I hope to pass this on at some point also to my trainees that they can be a scientist, even if they're not running a lab and they become an Institute director and that's also critically important.   Cindy St. Hilaire:        There's lots of ways to do science. Thank you all so much for joining me today. Either waking up at 5:00 AM or staying up past midnight, I think it is now in Japan or close to it. So Matt and I kind of made it out okay. It's like 8:00 or 9:00 AM.   Matthew DeBerge:      Thank you.   Hisayuki Hashimoto:   My apologies for this time zone difference.   Cindy St. Hilaire:        I'm very glad to make it work. Congratulations to all of you, your presentations. I forget which day of the week they are on at BCVS, but we are looking forward to the oral presentations of these and congratulations to all of you. You are amazing scientists and I know I'm really looking forward to seeing your future work so best of luck.   Matthew DeBerge:      Thank you.   Hisayuki Hashimoto:   Thank you.   Anja Karlstaedt:          Thank you so much.   Cindy St. Hilaire:        That's it for the highlights from the June 24th, July 8th and July 22nd issues of Circulation Research. Thank you for listening. Please check out the CircRes Facebook page and follow us on Twitter and Instagram with the handle at CircRes and hashtag Discover CircRes. Thank you to our guests. The BCVS Outstanding Early Career Investigator Award Finalists, Dr Hisayuki Hashimoto, Dr Matthew DeBerge and Dr Anja Karlstaedt. This podcast is produced by Ashara Ratnayaka, edited by Melissa Stoner and supported by the editorial team of Circulation Research. Some of the copy text for the highlighted articles is provided by Ruth Williams. I'm your host, Dr Cindy St. Hilaire. And this is Discover CircRes, you're on the go source for the most exciting discoveries in basic cardiovascular research. This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more information visit ahajournals.org.  

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.21.106963v1?rss=1 Authors: Kim, D. W., Liu, K., Wang, Z. Q., Zhang, Y. S., Bathini, A., Brown, M. P., Lin, S. H., Washington, P. W., Sun, C., Lindtner, S., Lee, B., Wang, H., Shimogori, T., Rubenstein, J. L. R., Blackshaw, S. Abstract: GABAergic neurons of the hypothalamus regulate many innate behaviours, but little is known about the mechanisms controlling their development. We previously identified hypothalamic neurons expressing the LIM homeodomain transcription factor Lhx6, also a master regulator of cortical interneuron development, as sleep-promoting. In contrast to telencephalic interneurons, hypothalamic Lhx6 neurons do not undergo long-distance tangential migration, and do not express cortical interneuronal markers such as Pvalb. Here, we show that Lhx6 is necessary for survival of hypothalamic neurons, and that Dlx1/2, Nkx2-2, and Nkx2-1 are each required for specification of spatially distinct subsets of hypothalamic Lhx6 neurons. We identify a broad range of neuropeptides that are enriched in spatially segregated subsets of hypothalamic Lhx6 neurons, and distinct from those seen in cortical neurons. These findings identify common and divergent mechanisms by which Lhx6 controls the development of GABAergic neurons in the hypothalamus compared to telencephalic interneurons. Copy rights belong to original authors. Visit the link for more info

Jane Ferguson: Hello. Welcome to episode 19 of Getting Personal: Omics of the Heart, the issue from August 2018. I am Jane Ferguson, and this podcast is brought to you by the Circulation: Genomic and Precision Medicine Journal and the American Heart Association Council on Genomic and Precision Medicine. Before I dive into the papers from this month, a reminder that early bird registration for AHA Scientific Sessions runs until September 4th, so go register now if you haven't already to take advantage of reduced rates. The meeting will be held in Chicago from November 10th through 12th, and it's the first year of the new three-day meeting format. It's already promising to be a really great meeting, and I'm hoping to see a lot of you there.     The August issue has a number of really interesting papers. First up, Gardar Sveinbjornsson, Eva Olafsdottir, Kari Stefansson, and colleagues from deCODE genetics-Amgen report that variants in NKX2-5 and FLNC cause dilated cardiomyopathy and sudden cardiac death. This team leveraged available DNA samples from the Icelandic population to carry out a genome-wide association study in 424 cases of dilated cardiomyopathy and over 337,000 controls. They applied whole genome sequencing to all of these samples, allowing them to identify common and rare variants. In total, they tested over 32 million variants.     They found two variants that were significantly associated with DCM at genome-wide significance, a missense variant in NKX2-5 and a frameshift in FLNC, both associated with heart failure and sudden cardiac death. Further, the NKX2-5 variant was associated with atrioventricular block and atrial septal defect. Although these variants are rare and not documented in other populations, they are significant contributors to familial DCM in Iceland. Because of the unique population structure of Iceland and known genealogy, the researchers were able to trace the NKX2-5 variant back to a common ancestor born in 1865. They traced the FLNC variants to a common ancestor born in 1595.     While the specific variants identified in this study may not be present in other populations, they are located in genes with known relevance for cardiac function. NKX2-5 encodes a cardiac transcription factor, which is required for embryonic cardiac development, and other variants in this gene have been associated with cardiac dysfunction in other populations. FLNC encodes filamin-C, a muscle cross-linking protein. Variants in FLNC have previously been ascribed to associate with myofibrillar myopathy, muscular dystrophy, and cardiomyopathy. This study adds to our knowledge of the genetics of dilated cardiomyopathy and supports screening for NKX2-5 and FLNC variants, particularly in the Icelandic population, which would allow for early intervention and monitoring in carriers.     Staying with the topic of dilated cardiomyopathy, Inken Huttner, Louis Wang, Diane Fatkin, and colleagues from the Victor Chang Cardiac Research Institute in Australia report that an A-band titin truncation in zebrafish causes dilated cardiomyopathy and hemodynamic stress intolerance. We actually talked to Dr. Wang about this research last year when he was presenting this as a finalist for the FGTB Young Investigator Award. You can go back in the archives to episode 10 from November 2017 if you'd like to hear more.     Titin mutations are responsible for a large number of cases of dilated cardiomyopathy, but there are also individuals with titin mutations that remain asymptomatic. This group used zebrafish as a model of human titin mutations and generated fish with a truncating variant in the A-band of titin, as has been identified in families with DCM. They found that homozygous mutants had a severe cardiac phenotype with premature death, but that heterozygous carriers survived into adulthood and developed spontaneous DCM. Prior to onset of DCM, the heterozygous fish had reduced baseline ventricular systolic function and reduced contractile response to hemodynamic stress, as well as ventricular diastolic dysfunction.     Overall, the mutant fish displayed impaired ability to mount stress responses, which may have contributed to development of disease. Extrapolating this to humans, this could suggest that hemodynamic stress may be a factor that contributes to timing and severity of disease in individuals with titin variants. Hemodynamic stress can be exerted by exercise, pregnancy, and other diseases contributing to ventricular volume overload. Modifying these hemodynamic stressors in at-risk subjects could potentially help to modulate the severity of DCM phenotypes.     Moving on to the topic of coronary artery disease, Vinicius Tragante, Daiane Hemerich, Folkert Asselbergs, and colleagues from University Medical Center Utrecht in the Netherlands report on druggability of coronary artery disease risk loci. This group was interested in using results from genome-wide association studies for CAD to identify new targets that may be amenable for drug repurposing. They used results from published GWAS for CAD and created a pipeline to integrate these loci with data on drug-gene interactions, chemical interactions, and potential side effects. They also calculated a druggability score based on the gene products to prioritize targets that are accessible and localized to increase the chance of a drug being able to find the target without affecting core systemic processes or housekeeping genes.     Their pipelines allowed them to identify three possible drug-gene pairs, including pentolinium to target CHRNB4, adenosine triphosphate to target ACSS2, and riociguat to target GUCY1A3. They also identified three proteins to be prioritized for drug development, including leiomodin 1, huntingtin-interacting protein 1, and protein phosphatase 2, regulatory subunit b-double prime, alpha). While these predictions were all made in silico and need to be extensively tested in clinical trials, the pipeline did identify many current therapies for CAD and myocardial infarction, including statins, PCSK9 inhibitors, and angiotensin II receptor blockers. These positive controls support that this method can successfully discover effective CAD therapies.     Staying on the topic of drugs, Kishan Parikh, Michael Bristow, and colleagues from Duke University report on dose response of beta-blockers in adrenergic receptor polymorphism genotypes. Two clinical trials have reported pharmacogenomic interactions between beta-blockers and beta-1 adrenergic receptor genotype in the setting of heart failure with reduced ejection fraction. In a retrospective analysis in almost 2,000 subjects from the BEST and HF-ACTION studies, the authors analyzed whether genotype at the Arg389Gly polymorphism in beta-1 adrenergic receptor, or an indel in the alpha-2C adrenergic receptor interacted with drug dose to affect mortality and hospitalization.     They found that ADRB1 genotype affected mortality in response to drug dose with less all-cause mortality in high versus no or low-dose beta-blockers in individuals homozygous for arginine at position 389, but not in individuals carrying a glycine at that position. In individuals on high-dose beta-blockers, genotype did not affect outcomes, but there was a significant difference by genotype in all-cause mortality in individuals on no or low-dose beta-blockers. These data support the guideline recommendations to use high-target doses of beta-blockers in HFrEF.     Switching gears towards precision medicine and genotype-guided approaches, Laney Jones, Michael Murray, and colleagues from Geisinger were interested in the patient's perspective. In their paper, Healthcare Utilization and Patients’ Perspectives After Receiving a Positive Genetic Test for Familial Hypercholesterolemia, they explored the impact of providing genotype test results for familial hypercholesterolemia to subjects participating in the MyCode Community Health Initiative. In MyCode, exome sequencing is conducted in participants, and results are returned for pathogenic and likely pathogenic variants in genes representing actionable conditions based on American College of Medical Genetics secondary findings and recommendations.     It is estimated that 3.5% of MyCode participants will be carriers of such variants, and this number may increase as more variants are discovered. In this pilot study, the authors screened for individuals with mutations in LDLR, APOB, or PCSK9, consistent with FH. They identified 28 individuals, of which 23 were eligible for inclusion in the study. Only five of the 23 subjects had previously been diagnosed with FH. Receipt of genetic test results led to change in medications in 39% of individuals. 96% of the subjects had previous LDL measurements, but only four subjects had ever met LDL goals. After genetic test results, three individuals met their LDL goals.     Seven individuals consented to participate in interviews about their experience. Almost all of these subjects already had a personal or family history of high cholesterol or heart disease, and all subjects felt that they were being adequately treated. Only three of the seven subjects mentioned using diet and exercise to control their high cholesterol, with most individuals being relatively unconcerned because they felt their medication was effective in controlling disease risk.     While the numbers studied here are too small for any statistical testing or inference, the paper describes the results from the interviews, including some excerpts from patients, which really highlight the complexities of returning results and of helping patients understand what their results mean. Given increasing genetic testing and returning of results, studies like this are really important to help us figure out the most effective ways to communicate results and support patients and their care providers.     Also from a patient-centric perspective, we have an article from Susan Christian, Joseph Atallah, and colleagues from the University of Alberta in Canada on when to offer predictive genetic testing to children at risk of an inherited arrhythmia or cardiomyopathy, the family perspective. This article considers the timing of cascade testing to predict inherited arrhythmias and cardiomyopathy in children of affected individuals. European and North American guidelines differ on when or if they recommend genetic testing in children.     In this study, surveys were circulated to foundations and patient groups to solicit familial perspectives on when genetic testing should be offered to children. In total, 213 individuals responded. In the case of long QT syndrome, 92% of respondents thought testing should be offered before the age of five, while 77% of respondents thought genetic testing should be offered before the age of 10 for hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy.     Overall, the potential benefits of genetic testing, including guiding therapies, sport participation, and decreasing worry were ranked more highly than potential risks of discrimination or increasing worry that could occur from genetic testing. Overall, the responses indicated that families would welcome the option of genetic testing for at-risk children from a young age and support initiating early discussions with families to explore costs and benefits of early genetic testing.     Finally in this issue, we have a review from Paul Franks and Nicholas Timpson from Lund University and the University of Bristol entitled Genotype-Based Recall in Complex Cardiometabolic Traits. This review looks at the increasing practice of selecting samples or individuals from larger cohorts or biobanks based on their genotype to carry out additional studies. The article focuses on examples of such genotype-based recall studies in cardiometabolic disease, highlights approaches and new methods, and discusses the ways these types of studies can be used to extend and supplement randomized trials and large population-based studies.     As always, you can find all the articles, accompanying editorials, and video summaries online. Our website recently underwent some redesigns and has moved. You should be redirected if you have the older site bookmarked, but you can also find us directly at ahajournals.org/journal/circgen. Also, thanks to everyone who participated in the Twitter poll last month. You were pretty evenly split on what you want to hear in the podcast, but please continue to leave suggestions and feedback on what we're doing and where we can improve things. That's it for the August issue of Circulation: Genomic and Precision Medicine. Thanks for listening, and tune in next month for more.    

Discussion of the paper: ‘Benign hereditary chorea related to NKX2.1: expansion of the genotypic and phenotypic spectrum’ The contributors in the podcast are as follows: Kathryn Peall – SPR in Adult Neurology, MRC Centre for Neuropsychiatric, Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Wales and Dr James Rice – Consultant in Pediatric Rehabilitation Medicine, Pediatric Rehabilitation Department, Women’s and Children’s Hospital, Adelaide, Australia. Read the paper here: http://onlinelibrary.wiley.com/doi/10.1111/dmcn.12323/pdf

Neuroendocrine tumors are a heterogeneous group of malignancies with an increasing prevalence. Since there is not much progress in therapy, model systems are urgently needed. We have a CEA424-SV40 TAg transgenic mouse model which develops spontaneous tumors in the antral region of the stomach. In addition, several cell lines derived from the tumor were established. Gene expression analysis of the tumor tissue as well as cell lines revealed neuroendocrine markers. Therefore we further characterized this model with special emphasis on the cells of origin and used it for testing new targeted treatment protocols. To analyze CEA424-SV40 TAg mouse model in more detail, tumor tissue as well as the cell lines derived from the primary tumor were investigated by immunohistochemistry, immunofluorescence, western blot, and ELISA. Antibodies used were directed at SV40 TAg, Ki-67, chromogranin A, chromogranin B, secretin, H+-K+-ATPase, glucagon, and transcription factors NeuroD1 and Nkx2.2. Plasma hormone levels of serotonin and secretin were measured by ELISA. Immunostainings of SV40 TAg and Ki-67 revealed highly proliferative tumors cells. The tumors stained intensively for the neuroendocrine markers chromogranin A, chromogranin B, secretin and glucagon. The tumor tissue as well as the cell lines expressed transcription factors NeuroD and Nkx2.2, which are involved in the differentiation of the neuroendocrine lineage. Hormone levels of serotonin and secretin in the plasma of the transgenic mice were dramatically elevated when compared with normal littermates, thus supporting the neuroendocrine phenotype. As the neuroendocrine phenotype of CEA424-SV40 TAg transgenic mouse was confirmed, molecularly targeted therapies were tested in this model system both in vitro and in vivo. Cell lines were tested for drug sensitivity with mTOR inhibitors (RAD001, NVP-BEZ235), paclitaxel, E2F inhibitor, HSP90 inhibitor, and p53 stabilizer Nutlin-3a. All the drugs tested in vitro could efficiently inhibit cell proliferation in a dose dependent manner. From these drugs the mTOR inhibitor RAD001 was chosen for the in vivo experiment. Daily feeding of 10 mg/kg RAD001 inhibited the tumor development and prolonged the survival time of the CEA424-SV40 TAg transgenic mice dramatically. The effects of the RAD001 treatment on tumor cells were achieved mainly through inactivating mTOR-p70S6K and mTOR-4EBP1 signaling as proven by western blot and immunohistochemistry. Still, some cells must develop escape mechanisms, since the tumor tend to grow. To gain a better understanding of the T antigen transforming mechanisms as well as the possible escape mechanisms, some efforts were made on the tumor originating cells in the CEA424-SV40 Tag transgenic mouse model. Possible candidates for these tumor originating cells in the stomach are the newly described epithelial as well as mesenchymal stem cells. In a first attempt, the expression feature of epithelial and mesenchymal stem cell markers were analyzed. Established cell lines as well as tumor tissue from the tumor bearing mice were investigated by reverse transcription PCR (RT-PCR), immunohistochemistry, immunofluorescence, western blot, and microarray analysis. From several markers analyzed, the tumor cell lines showed a high expression level of the potential epithelial stem cell marker Bmi1 in RT-PCR and cDNA expression array. This could be further substantiated by western-blotting and immunostaining. Consequently, Bmi1 message could also be found in the growing tumors both in mRNA and protein levels. Experiments using siRNA to knock down the SV40-TAg expression showed that the Bmi1 expression went down in the cell lines thus showing the interrelationship. On the other hand, the mesenchymal stem cell marker Etv1 was also found to be expressed in the tumor tissue and cell lines derived from the tumor. More interestingly, Etv1 expression level was up-regulated over the time course of the tumor development. From these, an Etv1 positive mesenchymal cell could be a possible candidate for transformation. Since the CEA-promoter used for the generation of the T-antigen transgenic animals contains Etv1 binding sites, it is tempting to speculate, that this may drive the transcription of the T antigen. In conclusion, our data provide convincing evidence that CEA424-SV40 TAg mice are a clinically relevant model for neuroendocrine tumor. Testing of molecularly targeted therapies both in vitro and in vivo offered promising candidates for further clinical evaluation. Thus, this new model system could be of great value not only for studies on the mechanisms of how SV40 TAg induces neuroendocrine tumors but also for exploring novel targeted therapy in a preclinical setting.

Defects of the NKX2-1 gene, encoding thyroid transcription factor-1, cause brain-thyroid-lung syndrome (MIM 610978), characterised by benign hereditary chorea, congenital hypothyroidism and respiratory disease. The case of a term infant with mild primary congenital hypothyroidism and neonatal persistent respiratory failure with fatal outcome at 10 months of age despite continuous ventilatory support is described. Congenital defects of genes known to disturb surfactant protein and lipid homeostasis (SFTPB, SFTPC, ABCA3) were excluded. Hypothyroidism prompted sequencing of NKX2-1, which revealed a heterozygous 29 bp deletion (c.278_306del29) disrupting the affected allele. Analysis of bronchoalveolar lavage fluid demonstrated an abnormally low amount of surfactant protein C (SP-C) in relation to SP-B, and low levels of surfactant phospholipids, indicating disturbance of SP and lipid homeostasis as a consequence of NKX2-1 haploinsufficiency. NKX2-1 haploinsufficiency may lead to lethal respiratory failure of the newborn due to disruption of pulmonary surfactant homeostasis. NKX2-1 gene analysis should be considered when investigating irreversible respiratory insufficiency of the newborn.

AIMS: The proliferative potential of pluripotent stem cell-derived cardiomyocytes is limited, and reasonable yields for novel therapeutic options have yet to be achieved. In addition, various clinical applications will require the generation of specific cardiac cell types. Whereas early cardiovascular precursors appear to be important for novel approaches such as reseeding decellularized hearts, direct cell transplantation may require ventricular cells. Our recent work demonstrated that MesP1 represents a master regulator sufficient to induce cardiovasculogenesis in pluripotent cells. This led to our hypothesis that 'forward programming' towards specific subtypes may be feasible via overexpression of distinct early cardiovascular transcription factors. METHODS AND RESULTS: Here we demonstrate that forced expression of Nkx2.5 similar to MesP1 is sufficient to enhance cardiogenesis in murine embryonic stem cells (mES). In comparison to control transfected mES cells, a five-fold increased appearance of beating foci was observed as well as upregulated mRNA and protein expression levels. In contrast to MesP1, no increase of the endothelial lineage within the cardiovasculogenic mesoderm was observed. Likewise, Flk-1, the earliest known cardiovascular surface marker, was not induced via Nkx2.5 as opposed to MesP1. Detailed patch clamping analyses showed electrophysiological characteristics corresponding to all subtypes of cardiac ES cell differentiation in Nkx2.5 as well as MesP1 programmed embryoid bodies, but fractions of cardiomyocytes had distinct characteristics: MesP1 forced the appearance of early/intermediate type cardiomyocytes in comparison to control transfected ES cells whereas Nkx2.5 led to preferentially differentiated ventricular cells. CONCLUSION: Our findings show proof of principle for cardiovascular subtype-specific programming of pluripotent stem cells and confirm the molecular hierarchy for cardiovascular specification initiated via MesP1 with differentiation factors such as Nkx2.5 further downstream.

Background: Pluripotent embryonic stem (ES) cells that can differentiate into functional cardiomyocytes as well as vascular cells in cell culture may open the door to cardiovascular cell transplantation. However, the percentage of ES cells in embryoid bodies (EBs) which spontaneously undergo cardiovascular differentiation is low (< 10%), making strategies for their specific labeling and purification indispensable. Methods: The human connexin 40 (Cx40) promoter was isolated and cloned in the vector pEGFP. The specificity of the construct was initially assessed in Xenopus embryos injected with Cx40-EGFP plasmid DNA. Stable Cx40-EGFP ES cell clones were differentiated and fluorescent cells were enriched manually as well as via fluorescence-activated cell sorting. Characterization of these cells was performed with respect to spontaneous beating as well as via RT-PCRs and immunofluorescent stainings. Results: Cx40-EGFP reporter plasmid injection led to EGFP fluorescence specifically in the abdominal aorta of frog tadpoles. After crude manual enrichment of highly Cx40-EGFP- positive EBs, the appearance of cardiac and vascular structures was increased approximately 3-fold. Immuno fluorescent stainings showed EGFP expression exclusively in vascular-like structures simultaneously expressing von Willebrand factor and in formerly beating areas expressing alpha-actinin. Cx40-EGFP-expressing EBs revealed significantly higher numbers of beating cardiomyocytes and vascular-like structures. Semiquantitative RT-PCRs confirmed an enhanced cardiovascular differentiation as shown for the cardiac markers Nkx2.5 and MLC2v, as well as the endothelial marker vascular endothelial cadherin. Conclusions: Our work shows the feasibility of specific labeling and purification of cardiovascular progenitor cells from differentiating EBs based on the Cx40 promoter. We provide proof of principle that the deleted CD4 (Delta CD4) surface marker-based method for magnetic cell sorting developed by our group will be ideally suitable for transference to this promoter. Copyright (c) 2008 S. Karger AG, Basel.

Embryonale Stammzellen stellen aufgrund ihrer Fähigkeit, in vitro in verschiedene Subtypen von Kardiomyozyten zu differenzieren, eine vielversprechende Quelle für eine spezifische Zellersatztherapie ischämischer Herzerkrankungen dar. Ein wesentliches Hindernis, das große therapeutische Potenzial embryonaler Stammzellen für klinische Zelltransplantationen zu nutzen, besteht darin, dass es bisher kein geeignetes Verfahren gibt, den gewünschten Zelltyp zu isolieren. Die Applikation hochaufgereinigter definierter Subpopulationen ist jedoch Voraussetzung, um optimale funktionelle Effekte zu erzielen und andererseits eine potenzielle intramyokardiale Teratomformation aus mittransplantierten undifferenzierten ES-Zellen zu vermeiden. Die Verwendung Zelltyp-spezifischer Promotoren zur Expression eines transgenen Oberflächenmarkers könnte die zellschonende und nicht immunogene Aufreinigung eines gewünschten aus ES-Zellen gewonnenen Zelltyps mit hoher Ausbeute ermöglichen und damit eine wichtige Basis für künftige Zelltransplantationen liefern. In der vorliegenden Arbeit wurde ein Protokoll etabliert, um mittels der magnetischen Zellsortierung (MACS), dem gegenwärtigen Goldstandard einer zellschonenden und effizienten Zellseparation, stabil transfizierte murine embryonale Stammzellen aufzureinigen. Für MACS wurden ES-Zellen markiert, die ein intrazellulär trunkiertes CD4-Oberflächenprotein (∆CD4) unter der Kontrolle des konstitutiv aktiven PGK-Promotors stabil exprimierten. Um die markierten Zellen in vivo fluoreszenzmikroskopisch detektieren zu können, erfolgte in einem Parallelansatz eine Fusion des ∆CD4 mit einem intrazellulären EGFP-Teil (∆CD4EGFP). Die Funktionalität dieses Fusionsproteins wurde ebenso gezeigt wie dessen Eignung für die MACS-Aufreinigung, mit welcher Reinheiten von über 97% erzielt wurden. Die Expression des ∆CD4-Moleküls ohne EGFP-Anteil führte nach MACS zu über 98% positiven vitalen Zellen. Dabei waren die jeweils erzielten Reinheiten unabhängig von dem Differenzierungszustand der Zellen und der initialen Frequenz positiver Zellen (0,6% bis 16%). Die Vitalität der aufgereinigten Zellen nach dem MACS-Prozess wurde dadurch belegt, dass diese in der Lage waren, zu reaggregieren und normale „Embryoid Bodies“ auszubilden, die Marker aller drei embryonaler Keimblätter exprimierten. Parallel zur Etablierung der MACS-Methode wurde der kardial spezifische humane 2,75kb Nkx2.5-Promotor über die Expression des in vivo-Markers EGFP in murinen embryonalen Stammzellen untersucht. Die fluoreszenzmikroskopischen und durchflusszytometrischen Ergebnisse korrelierten mit dem erwarteten embryonalen Aktivitätsprofil des Nkx2.5-Promotors. RT-PCR-Analysen früher kardialer Marker zeigten, dass der hNkx2.5-Promotor Zellen markiert, deren Expressionsmuster dem früher kardial determinierter Zellen entspricht. Der 2,75 kb lange hNkx2.5-Promotor bietet damit einen vielversprechenden Ansatz, kardiale Vorläuferzellen innerhalb des heterogenen Zellspektrums sich differenzierender ES-Zellen zu identifizieren. Ein Transfer auf das in dieser Arbeit etablierte MACS-System könnte die effiziente, zellschonende und nicht immunogene Aufreinigung kardialer Vorläuferzellen aus humanen ES-Zellen ermöglichen. Dieser Ansatz könnte die Therapie ischämischer Herzmuskelerkrankungen mit embryonalen Stammzellen der klinischen Anwendung einen entscheidenden Schritt näher bringen.