Podcasts about ccl2

Uveitis is a heterogenous group of inflammatory eye diseases for which current cytokine-targeted immune therapies are effective for only a subset of patients. Dr. Edmund Tsui is joined by Dr. Lynn M. Hassman and MD/PhD student Joseph B. Lin to explore potential common underlying mechanisms that exist for immune cell recruitment in uveitis in their Ophthalmology Science article, “Aqueous macrophages contribute to conserved CCL2 and CXCL10 gradients in uveitis” Aqueous Macrophages Contribute to Conserved CCL2 and CXCL10 Gradients in Uveitis. Lin, Joseph B. et al. Ophthalmology Science, Volume 4, Issue 4. The Ophthalmology-family of journals is now on Instagram. Follow aaojournal for clinical images, research articles, news, editorials, podcasts, and more! Sign up for the next Ophthalmology Journal Virtual Club on June 19, 2024, at https://store.aao.org/ophthalmology-virtual-journal-club.html

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.21.550077v1?rss=1 Authors: Santos, F. M., Melo, V. C., Araujo, S., Sousa, C. D. F., Moreira, T. P., Goncalves, M. R., Santos, A. C., Seabra, H. A., Costa, P. A. C., Barrioni, B. R., Souza, P. B., Pereira, M. d. M., Nogueira, M. L., Souza, D. G., Guimaraes, P. P., Texeira, M. M., Queiroz-Junior, C. M., Costa, V. V. Abstract: Mayaro virus (MAYV) is an emerging arbovirus member of the Togaviridae family and Alphavirus genus. MAYV infection causes an acute febrile illness accompanied by persistent polyarthralgia and myalgia. Understanding the mechanisms involved in arthritis caused by alphaviruses is necessary to develop specific therapies. In this work, we investigated the role of the CCL2/CCR2 axis in the pathogenesis of MAYV-induced disease. For this, WT C57BL/6J and CCR2-/- mice were infected with MAYV subcutaneously and evaluated for disease development. MAYV infection induced an acute inflammatory disease in WT mice. The immune response profile was characterized by an increase in the production of inflammatory mediators, such as IL-6, TNF and CCL2. Higher levels of CCL2 at the local and systemic levels, was followed by significant recruitment of CCR2+ macrophages and a cellular response orchestrated by these cells. CCR2-/- mice showed an increase in CXCL-1 levels, followed by a replacement of the macrophage inflammatory infiltrate by neutrophils. Additionally, absence of the CCR2 receptor protected mice from bone loss induced by MAYV. Accordingly, the silencing of CCL2 chemokine expression in vivo and the pharmacological blockade of CCR2 promoted a partial improvement in disease. Cell culture data support the mechanism underlying MAYV's bone pathology in which: i) MAYV infection promoted a pro-osteoclastogenic microenvironment mediated by IL-6, TNF and CCL2 and ii) migration of osteoclast precursors was dependent on the CCR2/CCL2 axis. Overall, these data contribute to the understanding of the pathophysiology of MAYV infection and to the identification future of specific therapeutic targets in MAYV-induced disease. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

As Veterans, we are all aware of the difficulties transition poses. Sometimes, Veterans are coming out with unhealed trauma so severe it is leading them to make decisions that result in legal issues. Fortunately, the civilian legal system saw that these Veterans were struggling from military trauma and decided to offer them a second chance. In 2013, the Veteran Treatment Court was established. Since then, most counties in every state have implemented this program. In 2015, Judge Stephens saw the need and established a VTC for Comal County in Texas. Donna and Jay talk with Judge Stephens about Veteran Treatment Court, what led him to bring it to his county, how it is structured, and what the future looks like. You'll also learn a few fun facts about Judge Stephens throughout the podcast. Trust us, you'll be surprised. Judge Stephens Bio Judge, Comal County Court at Law #2 - January 1, 2004 - present - a General Jurisdiction Court Law Office of Charles A. Stephens, II - September 1, 1989 - December 31, 2003 - a General Law Practice Smith, Barshop, Stoffer and Millsap - June 1984 - August 31, 1989 - Civil Litigation 1984 - Juris Doctor from St. Mary's University School of Law 1981 - Bachelor of Arts degree from The University of Texas at Austin Raised in Odessa, Texas Website: https://www.co.comal.tx.us/CCL2.htm FB - Charles Stephens IG - @CCAL2JUDGE Twitter - @ccal2 Veteran Justice Outreach Tune into our CHW Streaming Radio and the full lineup at cominghomewell.com Download on Apple Play and Google Play Online-Therapy.com ~ Life Changing Therapy Click here for a 20% discount on your first month. Donna's Links Website: www.rebel-llc.com Consulting/Coaching Book: Warrior to Patriot Citizen (2017) Blog: Taking Off The Armor IG: @thetransitioningwarrior Twitter: @wtpc FB: The Transitioning Warrior Jay's Links Website: https://j2servantleadership.com/ Book: Breaking Average (2020) Thank you for listening! Be sure to SHARE, LIKE and leave us a REVIEW!

As Veterans, we are all aware of the difficulties transition poses. Sometimes, Veterans are coming out with unhealed trauma so severe it is leading them to make decisions that result in legal issues.Fortunately, the civilian legal system saw that these Veterans were struggling from military trauma and decided to offer them a second chance. In 2013, the Veteran Treatment Court was established. Since then, most counties in every state have implemented this program.In 2015, Judge Stephens saw the need and established a VTC for Comal County in Texas.Donna and Jay talk with Judge Stephens about Veteran Treatment Court, what led him to bring it to his county, how it is structured, and what the future looks like. You'll also learn a few fun facts about Judge Stephens throughout the podcast. Trust us, you'll be surprised.Judge Stephens BioJudge, Comal County Court at Law #2 - January 1, 2004 - present - a General Jurisdiction CourtLaw Office of Charles A. Stephens, II - September 1, 1989 - December 31, 2003 - a General Law PracticeSmith, Barshop, Stoffer and Millsap - June 1984 - August 31, 1989 - Civil Litigation1984 - Juris Doctor from St. Mary's University School of Law1981 - Bachelor of Arts degree from The University of Texas at AustinRaised in Odessa, TexasWebsite: https://www.co.comal.tx.us/CCL2.htmFB - Charles StephensIG - @CCAL2JUDGETwitter - @ccal2Veteran Justice OutreachGet the ammo you need to seize your day at Soldier Girl Coffee with an automatic 10% off at checkout!Donna's LinksWebsite: www.rebel-llc.com Consulting/CoachingBook: Warrior to Patriot Citizen (2017)Blog: Taking Off The ArmorIG: @thetransitioningwarriorTwitter: @wtpcFB: The Transitioning WarriorJay's LinksWebsite: https://j2servantleadership.com/ Book: Breaking Average (2020) Follow us on our socialsYouTube @cominghomewellmilitaryInstagram @cominghomewellorganizationFacebook at Coming Home WellLinkedIn at Coming Home WellTwitter @ComingHomeWellThank you for listening! Be sure to SHARE, LIKE and leave us a REVIEW!

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.03.535167v1?rss=1 Authors: Ye, Q., Jo, J., Wang, C.-Y., Oh, H., Choy, T., Kim, K., D'Alessandro, A., Reshetnyak, Y. K., Jung, S. Y., Chen, Z., Marrelli, S. P., Lee, H. K. Abstract: Astrocytes play vital roles in blood-brain barrier (BBB) maintenance, yet how they support BBB integrity under normal or pathological conditions remains poorly defined. Recent evidence suggests pH homeostasis is a new cellular mechanism important for BBB integrity. In the current study, we investigated the function of an astrocyte-specific pH regulator, Slc4a4, in BBB maintenance and repair. We show that astrocytic Slc4a4 is required for normal astrocyte morphological complexity and BBB function. Multi-omics analyses identified increased astrocytic secretion of CCL2 coupled with dysregulated arginine-NO metabolism after Slc4a4 deletion. Using a model of ischemic stroke, we found that loss of Slc4a4 exacerbates BBB disruption and reactive gliosis, which were both rescued by pharmacological or genetic inhibition of the NO-CCL2 pathway in vivo. Together, our study identifies the astrocytic Slc4a4-NO-CCL2 axis as a pivotal mechanism controlling BBB integrity and repair, while providing insights for a novel therapeutic approach against BBB-related CNS 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/2023.02.15.528337v1?rss=1 Authors: Toro, C. A., Johnson, K. E., Hansen, J., Siddiq, M. M., Vasquez, W., Zhao, W., Graham, Z. A., Saez, J. C., Iyengar, R., Cardozo, C. P. Abstract: Membrane channels such as connexins (Cx), pannexins (Panx) and P2X7 receptors (P2X7R) are permeable to calcium ions and other small molecules such as ATP and glutamate. Release of ATP and glutamate through these channels is a key mechanism driving tissue response to traumas such as spinal cord injury (SCI). Boldine, an alkaloid isolated from the Chilean boldo tree, blocks both Cx hemichannels (HC) and Panx. To test if boldine could improve function after SCI, boldine or vehicle was administered to treat mice with a moderate severity contusion-induced SCI. Boldine led to greater spared white matter and increased locomotor function as determined by the Basso Mouse Scale and horizontal ladder rung walk tests. Boldine treatment reduced immunostaining for markers of activated microglia (Iba1) and astrocytic (GFAP) markers while increasing that for axon growth and neuroplasticity (GAP-43). Cell culture studies demonstrated that boldine blocked glial HC, specifically Cx26 and Cx30, in cultured astrocytes and blocked calcium entry through activated P2X7R. RT-qPCR studies showed that boldine treatment reduced expression of the chemokine Ccl2, cytokine IL-6 and microglial gene CD68, while increasing expression of the neurotransmission genes Snap25 and Grin2b, and Gap-43. Bulk RNA sequencing (of the spinal cord revealed that boldine modulated a large number of genes involved in neurotransmission in in spinal cord tissue just below the lesion epicenter at 14 days after SCI. Numbers of genes regulated by boldine was much lower at 28 days after injury. These results indicate that boldine treatment ameliorates injury and spares tissue to increase locomotor function. 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/2023.02.06.527377v1?rss=1 Authors: Yin, Z., Wu, L., Zhang, Y., Sun, Y., Chen, J. W., Subudhi, S., Ho, W., Lee, G. Y., Wang, A., Gao, X., Ren, J., Zhu, C., Zhang, N., Ferraro, G. B., Muzikansky, A., Zhang, L., Stemmer-Rachamimov, A., Mao, J., Plotkin, S. R., Xu, L. Abstract: Patients with Schwannomatosis (SWN) overwhelmingly present with intractable, debilitating chronic pain. There are no effective therapies to treat SWN. The drivers of pain response and tumor progression in SWN are not clear. The pain is not proportionally linked to tumor size and is not always relieved by tumor resection, suggesting that mechanisms other than mechanical nerve compression exist to cause pain. SWN research is limited by the lack of clinically-relevant models. Here, we established novel patient-derived xenograft (PDX) models, dorsal root ganglia (DRG) imaging model, and combined with single-cell resolution intravital imaging and RNASeq, we discovered: i) schwannomas on the peripheral nerve cause macrophage influx into the DRG, via secreting HMGB1 to directly stimulate DRG neurons to express CCL2, the key macrophage chemokine, ii) once recruited, macrophages cause pain response via overproduction of IL-6, iii) IL-6 blockade in a therapeutic setting significantly reduces pain but has modest efficacy on tumor growth, iv) EGF signaling is a potential driver of schwannoma growth and escape mechanism from anti-IL6 treatment, and v) combined IL-6 and EGFR blockade simultaneously controlled pain and tumor growth in SWN models. Our findings prompted the initiation of phase II clinical trial (NCT05684692) for pain relief in patients with SWN. 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/2023.01.10.523446v1?rss=1 Authors: Allison, R. L., Burand, A., Nieves Torres, D., Brandow, A. M., Stucky, C. L., Ebert, A. Abstract: Individuals living with sickle cell disease (SCD) experience severe recurrent acute and chronic pain. In order to develop novel therapies, it is necessary to better understand the neurobiological mechanisms underlying SCD pain. There are many barriers to gaining mechanistic insight into pathogenic SCD pain processes, such as differential gene expression and function of sensory neurons between humans and mice with SCD, as well as the limited availability of patient samples. These can be overcome by utilizing SCD patient-derived induced pluripotent stem cells (iPSCs) differentiated into sensory neurons (SCD iSNs). Here, we characterize the key gene expression and function of SCD iSNs to establish a model for higher-throughput investigation of intrinsic and extrinsic factors that may contribute to increased SCD patient pain. Importantly, identified roles for C-C Motif Chemokine Ligand 2 (CCL2) and endothelin 1 (ET1) in SCD pain can be recapitulated in SCD iSNs. Further, we find that plasma taken from SCD patients during acute pain increases SCD iSN calcium response to the nociceptive stimulus capsaicin compared to those treated with paired SCD patient plasma at baseline or healthy control plasma samples. Together, these data provide the framework necessary to utilize iSNs as a powerful tool to investigate the neurobiology of SCD and identify potential intrinsic mechanisms of SCD pain which may extend beyond a blood-based pathology. 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/2022.12.05.519158v1?rss=1 Authors: Carmon, H., Haley, E. C., Parikh, V., Tronson, N. C., Sarter, M. Abstract: Sign-tracking (ST) describes the propensity to approach and contact a Pavlovian reward cue. By contrast, goal-trackers (GTs) respond to such a cue solely by retrieving the reward. These behaviors index the presence of opponent cognitive-motivational traits, with STs exhibiting attentional control deficits, behavior dominated by incentive motivational processes, and vulnerability for addictive drug taking. Attentional control deficits in STs were previously attributed to attenuated cholinergic signaling, resulting from deficient translocation of intracellular choline transporters (CHTs) into synaptosomal plasma membrane. Here we investigated a post-translational modification of CHTs (poly-ubiquitination), and tested the hypothesis that elevated cytokine signaling in STs contributes to CHT modification. We demonstrated that intracellular CHTs, but not plasma membrane CHTs, are highly ubiquitinated in male and female sign-tracking rats when compared with GTs. Moreover, levels of cytokines measured in two brain regions, but not spleen, were higher in STs than in GTs. Activation of the innate immune system by systemic administration of the bacterial endotoxin lipopolysaccharide (LPS) elevated ubiquitinated CHT levels in cortex and striatum of GTs only, suggesting ceiling effects in STs. In spleen, LPS increased levels of most cytokines in both phenotypes. In cortex, LPS particularly robustly increased levels of the chemokines CCL2 and CXCL10. Phenotype-specific increases were restricted to GTs, again suggesting ceiling effects in STs. These results indicate that interactions between elevated brain immune modulator signaling and CHT regulation are essential components of the neuronal underpinnings of the addiction vulnerability trait indexed by sign-tracking. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

A new research paper was published in Oncotarget's Volume 13 on November 2, 2022, entitled, “MK256 is a novel CDK8 inhibitor with potent antitumor activity in AML through downregulation of the STAT pathway.” Acute myeloid leukemia (AML) is the most lethal form of AML due to disease relapse. Cyclin dependent kinase 8 (CDK8) is a serine/threonine kinase that belongs to the family of Cyclin-dependent kinases and is an emerging target for the treatment of AML. MK256, a potent, selective, and orally available CDK8 inhibitor was developed to target AML. In this new study, researchers Jen-Chieh Lee, Shu Liu, Yucheng Wang, You Liang, and David M. Jablons from the University of California San Francisco and Touro University sought to examine the anticancer effect of MK256 on AML. “In CD34+/CD38- leukemia stem cells, we found that MK256 induced differentiation and maturation.” Treatment of MK256 inhibited proliferation of AML cell lines. Further studies of the inhibitory effect suggested that MK256 not only downregulated phosphorylated STAT1(S727) and STAT5(S726), but also lowered mRNA expressions of MCL-1 and CCL2 in AML cell lines. Efficacy of MK256 was shown in MOLM-14 xenograft models, and the inhibitory effect on phosphorylated STAT1(S727) and STAT5(S726) with treatment of MK256 was observed in vivo. Pharmacologic dynamics study of MK256 in MOLM-14 xenograft models showed dose-dependent inhibition of the STAT pathway. Both in vitro and in vivo studies suggested that MK256 could effectively downregulate the STAT pathway. In vitro ADME, pharmacological kinetics, and toxicity of MK256 were profiled to evaluate the drug properties of MK256. “Our results show that MK256 is a novel CDK8 inhibitor with a desirable efficacy and safety profile and has great potential to be a promising drug candidate for AML through regulating the STAT pathway.” DOI: https://doi.org/10.18632/oncotarget.28305 Correspondence to: Jen-Chieh Lee -jenchieh.lee@ucsf.edu, Shu Liu - shu.liu@ucsf.edu Keywords: AML, CDK8, kinase inhibitor, STAT pathway, xenograft Video: https://www.youtube.com/watch?v=8bRgqTg9-c8 About Oncotarget: Oncotarget (a primarily oncology-focused, peer-reviewed, open access journal) aims to maximize research impact through insightful peer-review; eliminate borders between specialties by linking different fields of oncology, cancer research and biomedical sciences; and foster application of basic and clinical science. To learn more about Oncotarget, visit Oncotarget.com and connect with us on social media: Twitter – https://twitter.com/Oncotarget Facebook – https://www.facebook.com/Oncotarget YouTube – www.youtube.com/c/OncotargetYouTube Instagram – https://www.instagram.com/oncotargetjrnl/ LinkedIn – https://www.linkedin.com/company/oncotarget/ Pinterest – https://www.pinterest.com/oncotarget/ LabTube – https://www.labtube.tv/channel/MTY5OA SoundCloud – https://soundcloud.com/oncotarget For media inquiries, please contact: media@impactjournals.com

A new research paper was published in Oncotarget on August 3, 2022, entitled, “A novel mechanism of regulation of the oncogenic transcription factor GLI3 by toll-like receptor signaling.” The transcription factor GLI3 is a member of the GLI family and has been shown to be regulated by canonical hedgehog (HH) signaling through smoothened (SMO). Little is known about SMO-independent regulation of GLI3. “Hedgehog (HH) signaling is well known for its role in embryonic development, cancer and inflammation [1–4]. At the center of HH signaling are the 2 receptors patched (PTCH1) and smoothened (SMO) along with GLI transcription factors [5]. In the absence of HH ligand, PTCH1 inhibits SMO.” In this study, researchers (Stephan J. Matissek, Mona Karbalivand, Weiguo Han, Ava Boutilier, Estefania Yzar-Garcia, Laura L. Kehoe, Devin Storm Gardner, Adam Hage, Krista Fleck, Vicki Jeffers, Ricardo Rajsbaum, and Sherine F. Elsawa) from the University of New Hampshire and University of Texas Medical Branch identified toll-like receptor (TLR) signaling as a novel pathway regulating GLI3 expression. The researchers showed that GLI3 expression is induced by LPS/TLR4 in human monocyte cell lines and peripheral blood CD14+ cells. Further analysis identified TRIF, but not MyD88, signaling as the adapter used by TLR4 to regulate GLI3. Using pharmacological and genetic tools, they identified IRF3 as the transcription factor regulating GLI3 downstream of TRIF. “Furthermore, using additional TLR ligands that signal through TRIF such as the TLR4 ligand, MPLA and the TLR3 ligand, Poly(I:C), we confirm the role of TRIF-IRF3 in the regulation of GLI3.” They found that IRF3 directly binds to the GLI3 promoter region and this binding was increased upon stimulation of TRIF-IRF3 with Poly(I:C). Using Irf3−/− MEFs, the researchers found that Poly(I:C) stimulation no longer induced GLI3 expression. Finally, using macrophages from mice lacking Gli3 expression in myeloid cells (M-Gli3−/−), they found that in the absence of Gli3, LPS stimulated macrophages secrete less CCL2 and TNF-α compared with macrophages from wild-type (WT) mice. “Taken together, these results identify a novel TLR-TRIF-IRF3 pathway that regulates the expression of GLI3 that regulates inflammatory cytokines and expands our understanding of the non-canonical signaling pathways involved in the regulation of GLI transcription factors.” DOI: https://doi.org/10.18632/oncotarget.28261 Correspondence to: Sherine F. Elsawa – Email: sherine.elsawa@unh.edu Keywords: GLI3, inflammation, TLR About Oncotarget: Oncotarget (a primarily oncology-focused, peer-reviewed, open access journal) aims to maximize research impact through insightful peer-review; eliminate borders between specialties by linking different fields of oncology, cancer research and biomedical sciences; and foster application of basic and clinical science. To learn more about Oncotarget, visit Oncotarget.com and connect with us on social media: Twitter – https://twitter.com/Oncotarget Facebook – https://www.facebook.com/Oncotarget YouTube – www.youtube.com/c/OncotargetYouTube Instagram – https://www.instagram.com/oncotargetjrnl/ LinkedIn – https://www.linkedin.com/company/oncotarget/ Pinterest – https://www.pinterest.com/oncotarget/ LabTube – https://www.labtube.tv/channel/MTY5OA SoundCloud – https://soundcloud.com/oncotarget For media inquiries, please contact: media@impactjournals.com. Oncotarget Journal Office 6666 East Quaker Str., Suite 1A Orchard Park, NY 14127 Phone: 1-800-922-0957 (option 2)

This month on Episode 31 of Discover CircRes, host Cynthia St. Hilaire highlights two original research articles featured in the December 3 issue of Circulation Research. This episode also features a conversation with Drs Xavier Revelo, and Jop van Berlo from the University of Minnesota about their study, Cardiac Resident Macrophages Prevent Fibrosis and Stimulate Angiogenesis.   Article highlights:   Tong, et al. Alternative Mitophagy Protects Obesity Hearts Soetkamp, et al. Myofilament Phosphorylation in CDC Treated HFpEF   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. Hillaire from the Vascular Medicine Institute at the University of Pittsburgh. And today I'll be highlighting two articles presented in our December 3rd issue of CircRes, and I'll also speak with doctors, Xavier Revelo, and Jop van Berlo from University of Minnesota about their study, Cardiac Resident Macrophages Prevent Fibrosis and Stimulate Angiogenesis.   Cindy St. Hilaire:        The first article I want to share is titled, Alternative Mitophagy Protects the Heart Against Obesity-Associated Cardiomyopathy. The first doctor is Ming Ming Tong, and the corresponding author is Jun Sadoshima from Rutgers University. People with obesity or diabetes have an increased risk of developing cardiomyopathy, a condition which can eventually lead to heart failure. One of the major pathological features of obesity-related cardiomyopathy at the cellular level is a decrease in mitochondrial function. This decrease in mitochondrial function is likely due to a decrease in the canonical mitophagy pathway, which is a process by which dysfunctional mitochondria are degraded. However, a new process termed alternative mitophagy was recently discovered. When mice were fed a high fat diet for 24 weeks after only eight weeks, canonical mitophagy ceased. However alternative mitophagy steadily increased over the 24 weeks. Alternative mitophagy is regulated via the protein ULK1 and Rab9. The team went on to show that suppressing alternative mitophagy by knocking out ULK1, or expressing a loss of function, Rab9 mutant exacerbated the high fat diet induced cardiac dysfunction. Over expression of Rab9 in mouse hearts increased the alternative mitophagy pathway and protected the animals from cardiac dysfunction. These results suggest that pharmacological boosting of this ULK1 Rab9 mediated alternative mitophagy pathway might be a treatment strategy for preventing obesity related cardiomyopathy.   Cindy St. Hilaire:        The second article I want to share is titled Myofilament Phosphorylation in Stem Cell Treated Diastolic Heart Failure. The first doctor is Daniel Soetkamp and the corresponding author is Jenny Van Eyk from Cedar Sinai Medical Center. Weakness, fatigue and troubled breathing are among the symptoms experienced by someone suffering from heart failure with preserved ejection fraction, which is frequently called HFpEF. The pathology of the condition includes hypertrophy, fibrosis and stiffening of the heart and hyperphosphorylation of the cell sarcomere proteins. Because this hyperphosphorylation is a key contributor to HFpEF pathology, and because cardio sphere derived stem cells or CDCs have shown promise as a potential HFpEF treatment, this group investigated whether CDC treatment reduces phosphorylation levels of the sarcomere proteins in the heart. They found that administering CDCs to rats with HFpEF decreased the associated protein hyperphosphorylation, compared with that seen in untreated animals. Bioinformatic analysis revealed that protein kinase C or PKC is a prime suspect behind the phosphorylation. The authors suggest that CDCs alleviate HFpEF in part by reversing PKC-induced phosphorylation, and that PKC inhibition may be a desirable alternative treatment strategy, especially as it avoids regulatory issues associated with cell-based therapies.   Cindy St. Hilaire:        Today, I have Dr Xavier Revelo and Dr Jop van Berlo from the University of Minnesota and they're with me to discuss their study, Cardiac Resident Macrophages Prevent Fibrosis and Stimulates Angiogenesis. And this article is in our December 3rd issue of Circ Res. So, thank you both so much for joining me today.   Jop van Berlo:             Thanks for having us.   Cindy St. Hilaire:        Absolutely. So, your study is investigating the contribution of resident and monocyte drug of macrophages in cardiac remodeling, specifically in hypertrophy remodeling. So can you just introduce the topic of cardiac hypertrophy in humans, why that's not great to have, and then maybe tell us a little bit about what is known or what was known about the role of inflammatory cells in that hypertrophic remodeling.   Jop van Berlo:             Yeah, so absolutely. Cardiac hypertrophy is not a disease in and of itself in humans, but it is often a consequence of pathologies that can happen in patients, such as high blood pressure, hypertension or aortic valve stenosis, or if you've had a myocardial infarction the remaining myocardial may also become hypertrophic. We know that cardiac hypertrophy has downsides to it. People can develop sudden cardiac death when they have hypertrophic heart disease. We notice from population studies like the Framingham Heart Study and other studies, but it also increases the chance of developing heart failure later on. So even though cardiac hypertrophy by itself is not a disease, it is contributing to the cardiac pathology that can develop in patients and that can contribute to the development of heart failure.   Cindy St. Hilaire:        Great. So, what's the base level of knowledge of what is known regarding inflammatory cells in cardiac hypertrophy or cardiac hypertrophic remodeling?   Xavier Revelo:             So previous forecast focused on the role of infiltrating cells, specifically monocyte-derived macrophages, and generally these cells are pro-inflammatory and they aggravate the progression of heart failure. With Jop, we focus on, and what we think is exciting is the role of cardiac resident macrophages. And so, in our experiments, we decided to look at what's the role of these cardiac meta macrophages during pressure overload.   Cindy St. Hilaire:        That's a perfect segue to my next question, which is you obviously modeled this in mice, you used mice as your model and the method that you used to induce this hypertrophy is a technique called Transverse Aortic Constriction. So how does that actually work in a mouse and are there certain pros and cons to using that as a model for cardiac hypertrophy and, does it really recapitulate well, what happens in humans?   Jop van Berlo:             So, you're absolutely right that we use model systems to mimic what happens in humans and every model system has pros and cons to it. What we're trying to do here is to induce essentially acute cardiac pressure overload in a mouse model by inducing a constriction of the transverse aorta, right between the anomia and the left carotid artery. And we do this by ligating a needle on top of the transverse aorta that is of a specific size. And then we pull the needle out of the ligation and that immediately induces constriction. This is known to induce cardiac hypertrophy, and there are thousands of papers about this model as a model to induce cardiac hypertrophy. I think Howard Rockman was the first to publish this as a model of cardiac hypertrophy. Over the past decades, most of the research has focused on how cardiomyocytes within the heart respond to their stress and how they become hypertrophic. And I think what is new about our study is that instead of really focusing on the cardiomyocyte, we are focusing more on the non-cardiomyocyte compartments early after this stress is induced on the heart.   Cindy St. Hilaire:        That was one of the things I liked about this paper. We read about TAC a lot, the transaortic constriction model, but a lot of it is looking at either just the fibrotic cells or the scarring or the cardiomyocytes. So, this was, I thought a really nice unique take. So, one of the things I'm wondering is what are the functional differences between the systemic macrophages and these resident macrophages? I guess, resident to the cardiac tissue. And how does one tell the difference between these cells in the mice, but also in the humans? What is the human equivalent of those cells?   Xavier Revelo:             So, these cells, they rest in the macrophages in the cardiac tissue. One of the key differences from circulatory cells is the origin of the cells. In the heart, these cells self-renew, and they are from embryonic origins, as opposed to circulatory immune cells that come from the bone marrow. In terms of similarities between mice and humans, there are some markers that we can use to specifically study the cardiac resident macrophages. And these markers fortunately seem to be consistent between people and mice, which is advantages.   Cindy St. Hilaire:        That is good. That's always nice when it works out that way. So, you, you actually answered my next question, which was, are these residents macrophages a) able to self-replicate or are they from their own source? And so, regarding that developmental origin, how far apart are these lineages of the circulating monocytes versus the resident or the cardiac resident? How similar and how different, and how far back on the tree do they diverge? If we know it?   Xavier Revelo:             It's a complicated question.   Jop van Berlo:             And it's an active area of study right now, not just by us, but also by many other groups.   Xavier Revelo:             So, what we know is that regardless of origin, the cells are myeloid cells. So, they're the same lineage within the big family of immune cells. Having said that, the function of the cells is dictated by the origin, as well as the issue of residency. I forgot a second part of your question. Cindy St. Hilaire:        I'm wondering how much they diverge functionally from the circulating monocytes?   Xavier Revelo:             They do. It seems like the tissue factors and the residency dictates the function of the cells in general. This is a general comment. Resident cells seem to have a protective role. Sometimes they help with the repair and healing as opposed to infiltrating cells that come into the tissue and they cause inflammation, generally they aggravate disease progression.   Jop van Berlo:             But what I also find fascinating about these resident macrophages is they are not only found in the heart, but they're also found in all organs, and they all come from developmental origins. But if you compare the macrophages between these different organs, they resemble the organ itself more than macrophages between organs and that's based on recent work where people have compared resident macrophages from different organs. And I think that's just fascinating how this develops in the heart, but also in other organs as a way to protect specific organs from potentially dangerous signals.   Cindy St. Hilaire:        Yeah, that's so interesting. So, it's almost like their niche, their new residential home, is really informing their function. So, there's some kind of back and forth between that environment and the cell itself.   Jop van Berlo:             That's what we presume, but I don't think we truly understand how the niche is important in dictating the function of these resident macrophages. And I think we need to do a lot more research into how the niche of tissue resident macrophages has formed and how that then dictates the differentiation of these resident macrophages to give rise to certain functionalities.   Cindy St. Hilaire:        Maybe you can summarize in a couple short sentences or so what, what your key findings were.   Jop van Berlo:             The main findings of our study is that very early after the induction of acute cardiac pressure overload, there is a high level of inflammation happening in the heart. And this allows the replication of resident macrophages and our study showed that these resident macrophages are really important for a protective mechanism within the heart to allow the heart to deal with this increased pressure in a heart. And what they do is they stimulate the formation of new block vessels, also known as angiogenesis and furthermore, they inhibit the formation of scar tissue or fibrosis, and we used different ways to substantiate these conclusions.   Xavier Revelo:             We studied cardiac-resident macrophages as one population. But one thing we learned in this study is that these macrophages are highly diverse. And so, using our techniques, we discover that within cardiac macrophages, we have 11 different subsets. And so, our future studies will be aiming at understanding the precise role of these different subsets that we think have different roles in pressure overload.   Cindy St. Hilaire:        One of the things I was thinking about is these 11 subsets, do they represent kind of end stage fully differentiated resident macrophages, meaning 11 different types, or are they kind of representing maybe the different stages that get to the one end type? Do we have a sense of what's going on?   Xavier Revelo:             I don't think it's completely understood my take on that is that these different subsets they can represent different activation states or functional subsets that we don't really understand why is that we have this diversity?   Jop van Berlo:             I think one of the aspects that we as a field need to work on is to better understand that complexity of immune cells that reside within an organ and associate that complexity to specific functionalities. And right now, the field is mostly lacking in technologies that allow us to do this. For example, we cannot culture these resident macrophages right now. We don't know the proper culturing conditions that allow us to test functional differences between subsets of macrophages. We don't have very good genetic tools to dissect these specific subsets of macrophages. And I think those are important areas that the field and us of course need to work on in the coming years.   Cindy St. Hilaire:        Every layer of discovery, just brings like 10 more layers complexity, or 11 more co-layers of complexity in this case.   Jop van Berlo:             Which is why we all love science!   Cindy St. Hilaire:        Exactly, exactly. It's a drug that, that keeps on giving. So, one of your experiments, I forget which number, I think figure five or six or something like that, but in wild type mice, you went on to use an anti CD115 antibody. And because that treatment others, as well as yourselves has shown depletes the resident macrophages. And, and one thing I thought was really interesting. I just want to hear how you unpack it. And that is in the wild type mice that were treated with the anti CD115 antibody. You found that the depletion of the resident macrophages exacerbated the adverse remodeling and it increased fibrosis, it decreased angiogenesis, but when you did the same thing in a CCR2 knockout mouse in that mouse, they don't have the circulating macrophages, but they also don't have the resident macrophages. They were protected from the increased fibrosis, but there was no change in the angiogenesis. And I was just wondering if you could unpack these results for me and kind of talk about the competing roles of the resident and the non-resident macrophage in this pathogenesis.   Jop van Berlo              So I think you highlight a really important experiment that we performed that try to dissect the protective versus damaging effects of different subsets of macrophages within the heart. We know that if you delete the receptor CCR2, that circulating monocytes cannot extravasate and enter the tissue in response to the cytokine CCL2 that is produced by the myocardium. So, using the CCR2 knockout, we essentially blocked the invasion of circulating monocytes into the myocardium to become monocyte-derived macrophages. And we knew from the literature that, especially the monocyte-derived macrophages, were pro fibrotic. So, we wanted to discern the effects on fibrosis between resident macrophages and monocyte derived macrophages. So, we were happy to indeed see that when we blocked extravasation of circulating monocytes and blocked them to become macrophages, that we indeed reduce the amount of fibrosis that we observed within the heart.                                       I think the difficulty here that we observed that we don't have a very good explanation for right now are the effects on angiogenesis. And I think what this highlights is that there are many, many more complexities than just the resident and recruited macrophages on the development of angiogenesis because when we block tissue resident macrophages, are we actually depleting tissue resident macrophages? We didn't completely block the development of angiogenesis. We merely inhibited this by a little bit. And so, I think there are many more actions happening within the heart in response to stress than just the immune cells. And I think it highlights how complex a living organ really is. And we always try to do reductionist experiments to try to understand the functioning of specific aspects of that organ, but it's much more complex than just one cell type doing one thing and another cell type doing another thing.   Xavier Revelo:             One potential explanation to this complexity is the fact that when we deplete resident macrophages, the monocyte-derived macrophages, the infiltrating macrophages, they can replenish those resident macrophages. And so, whether there's a difference between the original resident macrophages compared to the replacing macrophages is unknown. And so, all these complexities can perhaps explain that different phenotypes that we observed in terms of angiogenesis.   Cindy St. Hilaire:        What do your findings suggest about potential therapies or you even potential therapeutic targets? Is it possible in a human to be able to target one or the other macrophage population? I know a lot of your experiments, because it's an experiment, you're targeting the depletion of macrophages before to see the effects, but are we able to possibly activate or stimulate their production, post MI for example?   Xavier Revelo:             Yeah, absolutely. So, thinking about cardiomyocyte independent interventions that can enhance the preparation process of any stressed heart, we could see potential in manipulating resident macrophages, specifically enhancing the functions of these resident macrophages that will help us heal and prevent fibrosis and enhance angiogenesis. So, we think that future studies need to look at what factors can be manipulated to enhance the function and survival of these resident macrophages.   Jop van Berlo:             One important aspect of our study that we don't highlight is that after this large increase in tissue resident macrophages, that we observed within the first week after cardiac pressure overload, these cells actually disappear. And right now, we don't really know the signals that are important for mediating that disappearing of cells. And we don't know this whether maintenance of these signals could improve longer beneficial effects of tissue resident macrophages.   Cindy St. Hilaire:        Interesting. I guess we know some questions you're going to start to ask in the future.   Jop van Berlo:             Absolutely. There's always more questions to answer in science.   Cindy St. Hilaire:        Well, great. Well, Dr Revelo, Dr van Berlo. Thank you so much for joining me today. Congrats on a wonderful paper and we look forward to these future studies.   Jop van Berlo:             Thank you.   Xavier Revelo:             Thank you.   Cindy St. Hilaire:        That's it for the highlights from the December 3rd issue 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 #DiscovererCircRes. Thank you to our guests, Dr Xavier Revelo and Jop van Berlo. This podcast is produced by Ishara Ratnayaka, edited by Melissa Stoner and supported by the editorial team of Circulation Research. Some of the copy text for highlighted articles is provided by Ruth Williams. I'm your host, Dr Cindy St. Hillaire. And this is Discover CircRes, your-on-the-go source for the most exciting discoveries in basic cardiovascular research. This program is copyright of the American Heart Association, 2021. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or the American Heart Association for more information visit aha journals.org.  

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.08.332007v1?rss=1 Authors: Palomino-Antolin, A., Narros-Fernandez, P., Farre-Alins, V., Sevilla-Montero, J., Decouty-Perez, C., Lopez-Rodriguez, A. B., Fernandez, N., Monge, L., Casas, A. I., Calzada, M. J., Egea, J. Abstract: Background and purpose: Post-ischemic inflammation contributes to worsening of ischemic brain injury and in this process, the inflammasomes play a key role. Inflammasomes are cytosolic multiprotein complexes which upon assembly activate the maturation and secretion of the inflammatory cytokines IL-1{beta} and IL-18. However, participation of the NLRP3 inflammasome in ischemic stroke remains controversial. Our aims were to determine the role of NLRP3 in ischemia and to explore the mechanism involved in the potential protective effect of the neurovascular unit. Methods: WT and NLRP3 knock-out mice were subjected to ischemia by middle cerebral artery occlusion (60 minutes) with or without treatment with MCC950 at different time points post-stroke. Brain injury was measured histologically with 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results: We identified a time-dependent dual effect of NLRP3. While neither the pre-treatment with MCC950 nor the genetic approach (NLRP3 KO) proved to be neuroprotective, post-reperfusion treatment with MCC950 significantly reduced the infarct volume in a dose-dependent manner. Importantly, MCC950 improved the neuro-motor function and reduced the expression of different pro-inflammatory cytokines (IL-1{beta}, TNF-), NLRP3 inflammasome components (NLRP3, pro-caspase-1), protease expression (MMP9) and endothelial adhesion molecules (ICAM, VCAM). We observed a marked protection of the blood-brain barrier (BBB), which was also reflected in the recovery of the tight junctions proteins (ZO-1, Claudin-5). Additionally, MCC950 produced a reduction of the CCL2 chemokine in blood serum and in brain tissue, which lead to a reduction in the immune cell infiltration. Conclusions: These findings suggest that post-reperfusion NLRP3 inhibition may be an effective acute therapy for protecting the blood-brain barrier in cerebral ischemia with potential clinical translation. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.18.254649v1?rss=1 Authors: Audrain, M., Haure-Mirande, J.-V., Mleczko, J., Wang, M., Griffin, J. K., Fraser, P., Zhang, B., Gandy, S., Ehrlich, M. E. Abstract: Microglial TYROBP (also known as DAP12) has been identified by computational transcriptomics as a network hub and driver in late-onset sporadic Alzheimer's disease (AD) and as an important regulator of the microglial environmental sensing function. TYROBP is the transmembrane adaptor of AD-related receptors TREM2 and CR3, but importantly, TYROBP interacts with many other receptors, and little is known about its roles in microglial action and/or in the pathogenesis of AD. Herein, using dual RNA in situ hybridization and immunohistochemistry, we demonstrate that endogenous Tyrobp transcription is increased specifically in recruited microglia in the brains of wild-type and AD-related mouse models. To determine whether chronically elevated TYROBP might modify microglial phenotype and/or progression of AD pathogenesis, we generated a novel transgenic mouse overexpressing TYROBP in microglia. TYROBP-overexpressing mice were crossed with either APP/PSEN1 or MAPTP301S mice, resulting in a decrease of the amyloid burden in the former and an increase of TAU phosphorylation in the latter. Apolipoprotein E (Apoe) transcription was upregulated in MAPTP301S mice overexpressing TYROBP and transcription of genes previously associated with Apoe, including Axl, Ccl2, Tgfb and Il6, was altered in both APP/PSEN1 and MAPTP301S mice overexpressing TYROBP. Lastly, Tyrobp and Apoe mRNAs were clearly increased in Trem2-null mice in microglia recruited around a cortical stab injury or amyloid-beta deposits. Conversely, microglial Apoe mRNA level was dramatically diminished when Tyrobp was absent. Our results provide compelling evidence that TYROBP-APOE signaling in the microglial sensome does not require TREM2. We propose that activation of a TREM2-independent TYROBP-APOE signaling could be an early or even initiating step in the transformation of microglia from the homeostatic phenotype to the Disease-Associated Microglia (DAM) phenotype. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.17.254888v1?rss=1 Authors: Mohammed, S., Nicklas, E. H., Thadathil, N., Selvarani, R., Royce, G. H., Richardson, A., Deepa, S. S. Abstract: Mice deficient in the antioxidant enzyme Cu/Zn-superoxide dismutase (Sod1-/- or Sod1KO mice) develop spontaneous hepatocellular carcinoma (HCC) with age. Similar to humans, HCC development in Sod1KO mice progresses from fatty liver disease to non-alcoholic steatohepatitis (NASH) with fibrosis, which eventually progresses to HCC. Because liver inflammation is the main mechanism that drives the disease progression in chronic liver disease (CLD) and because necroptosis is a major source of inflammation, we tested the hypothesis that increased necroptosis in the liver plays a role in increased inflammation and progression to fibrosis and HCC in Sod1KO mice. Phosphorylation of MLKL (P-MLKL), a well-accepted marker of necroptosis, and expression of MLKL protein were significantly increased in the livers of Sod1KO mice compared to WT mice indicating increased necroptosis. Similarly, phosphorylation of RIPK3 and RIPK3 protein levels were also significantly increased. Markers of pro-inflammatory M1 macrophages, NLRP3 inflammasome, and transcript levels of pro-inflammatory cytokines and chemokines, e.g., TNF, IL-6, IL-1{beta}, and Ccl2 that are associated with human NASH and HCC, were significantly increased. Markers of fibrosis and oncogenic transcription factor STAT3 were also upregulated in the livers of Sod1KO mice. Short term treatment of Sod1KO mice with necrostatin-1s (Nec-1s), a necroptosis inhibitor, significantly reduced necroptosis, pro-inflammatory cytokines, fibrosis markers and STAT3 activation. Our data show for the first time that necroptosis-mediated inflammation contributes to fibrosis and HCC progression in Sod1KO mice, a mouse model of accelerated aging and progressive HCC development. These findings suggest that necroptosis might be a target for treating NASH and HCC. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.21.213397v1?rss=1 Authors: Park, J. E., Guo, X., Liou, K. C. K., Lynn, S. E., Ng, S. S., Meng, W., Lim, S. C., Leow, M. K.-S., Richards, A. M., Pennington, D. J., McCarthy, N. E., de Kleijn, D. P. V., Sorokin, V., Ho, H. H., Sze, S. K. Abstract: Abnormal matrix deposition on vessels and recruitment of inflammatory cells into the arterial wall are critical events in atherosclerotic plaque formation. Fibronectin protein is a key matrix component that exhibits high levels of deamidation in atherosclerotic plaques and blood plasma, but it is unclear how this structural change impacts on endothelial function or modifies interactions with recruited leukocytes. This study aimed to determine how deamidation-induced isoDGR motifs in fibronectin influence extracellular matrix accumulation on endothelial cells, and to investigate possible effects on integrin outside-in signalling in matrix-bound monocytes which are key mediators of human atherosclerosis. Blood plasma fibrinogen and fibronectin displayed marked accumulation of isoDGR motifs in ischemic heart disease (IHD) as determined by ELISA analysis of patients undergoing coronary artery bypass grafting compared with age-matched healthy controls. Biochemical and functional assays confirmed that isoDGR-containing fibronectin promoted activation of integrin {beta}1 in monocytes and facilitated protein deposition and fibrillogenesis on endothelial cell layers. In addition, isoDGR interactions with integrins on the monocyte cell surface triggered an ERK:AP-1 signalling cascade that induced potent secretion of chemotactic mediators (including CCL2, CCL4, IL-8, and TNF), that promoted further leukocyte recruitment to the assembling plaque. Fibronectin deamidation forms isoDGR motifs that increase binding to {beta}1 integrins on the surface of endothelial cells and monocytes. Subsequent activation of integrin outside-in signalling pathways elicits a range of potent cytokines and chemokines that drive additional leukocyte recruitment to the developing atherosclerotic matrix and likely constitutes a key early event in progression to IHD. Copy rights belong to original authors. Visit the link for more info

The TWiV team covers outbreaks of eastern equine encephalitis virus in the US and poliovirus in the Philippines, and explain how a chemokine induced by HIV-1 infection helps release more virus particles from cells. Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, Kathy Spindler, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Poliomyelitis returns to the Philippines (Mashable, virology blog) EEE in the USA (Am J Trop Med Hyg) Chemokine helps HIV-1 release (eLIFE) Image credit Letters read on TWiV 567 Timestamps by Jolene. Thanks! Weekly Science Picks Brianne - History of infectious disease before/after vaccines Alan - NIH Ham Radio Club Rich - Renewable jet fuel from air Dickson - Newly Discovered Comet Is Likely Interstellar Visitor Kathy - How professors spend their time Vincent - Non-polio enterovirus surveillance network Listener Picks Alexey - Periodic Table Podcasts and Videos Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

The TWiV team covers outbreaks of eastern equine encephalitis virus in the US and poliovirus in the Philippines, and explain how a chemokine induced by HIV-1 infection helps release more virus particles from cells. Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, Kathy Spindler, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Poliomyelitis returns to the Philippines (Mashable, virology blog) EEE in the USA (Am J Trop Med Hyg) Chemokine helps HIV-1 release (eLIFE) Image credit Letters read on TWiV 567 Timestamps by Jolene. Thanks! Weekly Science Picks Brianne - History of infectious disease before/after vaccines Alan - NIH Ham Radio Club Rich - Renewable jet fuel from air Dickson - Newly Discovered Comet Is Likely Interstellar Visitor Kathy - How professors spend their time Vincent - Non-polio enterovirus surveillance network Listener Picks Alexey - Periodic Table Podcasts and Videos Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

Listen to Kelly Langert and Evan Stubbs discussing their recent ASN NEURO paper on how increased CCL2 and ICAM-1 expression in response to TNFα may facilitate recruitment and trafficking of autoreactive leucocytes across the blood-nerve barrier in autoimmune disorders, including Guillain-Barre syndrome

Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain.

Die von intrinsichen renalen Zellen und infiltrierenden Leukozyten exprimierten Zytokine sind zentrale Vermittler entzündlicher Nierenerkrankungen. Tumor Nekrose Faktor-α (TNF) ist ein solches proinflamatorisches Zytokin, das in der glomerulären Entzündungsreaktion involviert ist. Die funktionelle Rolle von TNF wurde in Tiermodellen der Glomerulonephritis belegt. Die biologischen Effekte von TNF werden durch die beiden funktionell eigenständigen TNF-Rezeptoren TNFR1 (CD120a) und TNFR2 (CD120b) vermittelt. Neuere Daten zeigen, dass in Modellen einer Immunkomplex-Glomerulonephritis wie der nephrotoxische Serumnephritis die beiden TNF-Rezeptoren in vivo unterschiedliche Funktionen bei der glomerulären Entzündung vermitteln können. Der vorliegenden Arbeit liegt die Hypothese zugrunde, dass Tnfr1 und Tnfr2 unterschiedliche inflammatorische TNF-Effekte in Glomeruli vermitteln. Daher war das Ziel dieser Arbeit, Expression und Funktion der beiden TNF-Rezeptoren in Maus-Glomeruli zu charakterisieren und die Tnfr-abhängig exprimierten Entzündungsmediatoren in Maus-Glomeruli zu identifizieren. Aufbauend auf den Ergebnissen dieser Arbeit könnten selektive, Tnfr-spezifische Therapien zur Hemmung der glomerulären Entzündungsreaktion entwickelt werden. Zudem wurde in dieser Arbeit die funktionelle Rolle der beiden TNF-Rezeptoren im MRL/lpr-Mausmodell der Lupusnephritis untersucht, um eine selektive Tnfr-Blockade als mögliche Therapiestrategie zu charakterisieren. Hierfür war eine Rückkreuzung von Tnfr1- und Tnfr2-defizienten C57BL/6J-Mäusen in den MRL/lpr-Hintergrund erforderlich. Um TNF-Rezeptor-1- und 2-vermittelte inflammatorische Signalwege in Glomeruli zu identifizieren wurde die Expression und die Funktion der beiden TNF-Rezeptoren in Mausnieren, in isolierten Glomeruli ex vivo und murinen glomerulären Endothel- und Mesangialzellen in vitro untersucht. In normaler Mausniere konnte eine Tnfr1- und Tnfr2-mRNA- und Protein-Expressionen präferentiell in Glomeruli im Vergleich zum Tubulointerstitium nachgewiesen werden. Die Expression von beiden TNF-Rezeptoren und die TNF-induzierte Induktion von Tnfr2-mRNA-Expression wurde auch in vitro sowohl in murinen glomerulären Endothel- als auch Mesangialzelllinien bestätigt. Die prominente glomeruläre TNF-Rezeptor-Expression korrelierte mit einer konstitutiven glomerulären mRNA-Expression von Adhäsionsmolekülen wie Icam-1, Vcam-1, E- und P-Selektin und Chemokinen wie Ccl2, Ccl3 und Ccl5. Eine intraperitoneale TNF-Injektion induzierte die Expression dieser Mediatoren präferentiell in Glomeruli. Diese in vivo TNF-Exposition führte zu einer raschen glomerulären Akkumulation von Leukozyten einschließlich Neutrophilen und mononukleären Phagozyten, die mittels einer kompartimentspezifischer Durchflußzytometrie analysiert wurden. Um Tnfr-abhängige inflammatorische Effekte in intrinsischen glomerulären Zellen unabhängig von infiltrierenden Leukozyten zu untersuchen, wurde eine Microarray-Gene-Expressionsanalyse an intakten Glomeruli durchgeführt, die aus Wildtyp und Tnfr-defizienten Mäusen isoliert und anschließend mit TNF ex vivo stimuliert wurden. Die meisten TNF-Effekte wurden ausschließlich durch Tnfr1 vermittelt, unter anderem die induzierte mRNA-Expression von Adhäsionsmolekülen, proinflammatorischen Chemokinen, Komplement-Faktoren und proapoptotischen Molekülen. Im Gegensatz dazu fanden wir nur vier Tnfr2-abhängig exprimierte Gene, einschließlich einer kleinen GTPase der Rab-Familie (Rab6b). Diese Ergebnisse wurden durch quantitative RT-PCR-Analysen von TNF-stimulierten Glomeruli und primären Mesangialzellen bestätigt. Weitere Untersuchungen zeigten allerdings auch einen Beitrag von Tnfr2 bei der gesteigerten glomerulären Expression von Adhäsionsmolekülen und Chemokine nach Stimulation mit niedrigen TNF-Konzentrationen auf. Im Gegensatz zur Wildtyp-Kontrolle fehlte in TNF-stimulierten Tnfr1-defizienten Glomeruli die Sekretion verschiedener proinflammatorischer Chemokine beinahe vollständig. Interessanterweise war die Proteinexpression auch in Tnfr2-defizienten Glomeruli signifikant herunterreguliert. Folglich sind die meisten inflammatorischen TNF-Effekte in Glomeruli via Tnfr1 durch die induzierte Expression von proinfammatorischen Mediatoren wie Adhäsionsmolekülen und Chemokinen vermittelt. Darüber hinaus dürfte Tnfr2 zu dieser inflammatorischen Antwort beitragen, wenn Glomeruli niedrigen TNF-Konzentrationen ausgesetzt sind. Ferner scheint Tnfr2 posttranskriptionell die Chemokinsekretion in Glomeruli nach einer TNF-Exposition zu beeinflussen, möglicherweise durch die Tnfr2-abhängig exprimierte Rab GTPase Rab6b, die am intrazellulären Transport und der Sekretion von inflammatorischen Molekulen beteiligt sein könnte. In Bezug auf Tnfr-spezifische, anti-inflammatorische Therapien weisen die hier präsentierten Ergebnisse somit darauf hin, dass eine selektive Tnfr1-Blockade eine glomeruläre, insbesondere durch Granulozyten und Makrophagen vermittelte Entzündung verbessern könnte, möglicherweise bei geringer Hemmung immunregulatorischer und antimikrobieller Funktionen von TNF, die redundant durch Tnfr2 vermittelt werden könnten. Dagegen erscheint aufgrund der erhobenen Daten im MRL/lpr-Mausmodell eine Blockade von TNF oder beider Rezeptoren bei der Lupusnephritis, in der glomeruläre Neutrophileninfiltrate keine entzündliche Rolle spielen, weniger erfolgversprechend. Gleichzeitig weisen die vorliegenden Ergebnisse auf eine immunsuppressive, die systemische Immunreaktivität beim SLE begrenzende Funktion von Tnfr2 hin.

Die vorliegende Arbeit untersuchte die Rolle der Perizyten bei steriler Inflammation. Bisher war in diesem Zusammenhang der Einfluss der Perizyten nicht bekannt, ebenso wenig ob und wie sie zu Entzündungsreaktionen beitragen. Weiterhin war der Einfluss der Perizyten auf die interstitielle Migration myeloider Zellen in vivo unerforscht. Hier konnte gezeigt werden, dass Perizyten durch eine Vielzahl von Rezeptoren wie TLR2, TLR4, TNFR1, FPR2 in der Lage sind inflammatorische Reize zu detektieren und daraufhin einen proinflammatorischen Phänotyp annehmen. Dieser ist durch die vermehrte Expression von NLRP3 sowie des Adhäsionsmoleküls ICAM-1 und die Sekretion von Chemokinen wie CXCL1, IL8 und CCL2 gekennzeichnet. Weiterhin wird das Chemokin-ähnliche Molekül MIF von aktivierten Perizyten sowohl sezerniert als auch an der Oberfläche präsentiert. Die ausgeschütteten Chemokine beeinflussen wiederum Monozyten und neutrophile Granulozyten durch ihre chemotaktische Wirkung. Auch konnte ein anti-apoptotischer sowie aktivierender Effekt der Perizyten auf neutrophile Granulozyten gezeigt werden, was die Überlebensdauer dieser Zellen im interstitiellen Gewebe signifikant verlängert. Anhand eines Mausmodells und der 2-Photonen Mikroskopie wurde gezeigt, dass Perizyten auch in vivo einen entscheidenden Beitrag zur Rekrutierung neutrophiler Granulozyten und Monozyten zur Inflammation leisten. Zum ersten Mal wurde die Interaktion myeloider Zellen mit Perizyten in vivo visualisiert und genauer charakterisiert. Diese Interaktion beeinflusst die interstitielle Migration neutrophiler Granulozyten und Monozyten abhängig davon, ob ein Stimulus für gerichtete oder ungerichtete Migration vorliegt. Es wurde deutlich, dass Perizyten sowohl einen chemotaktischen als auch einen haptotaktischen Reiz auf myeloide Leukozyten ausüben, was an einer Polarisierung der Zellen zu erkennen ist. Ebenso tragen sie durch die Interaktion zur Aktivierung der myeloiden Zellen in vivo bei. Diese Arbeit leistet demnach einen Beitrag zur genaueren Definition der Rolle von Perizyten bei steriler Inflammation. Hierfür wurden die zellulären und molekularen Mechanismen in vitro und die in vivo ablaufenden Prozesse bei der interstitiellen Migration myeloider Zellen genauer charakterisiert. Dabei konnten Perizyten als neuer Zelltyp identifiziert werden, der Gewebeschäden detektiert und aktiv zur akuten Entzündungsreaktion beiträgt indem er die Rekrutierung und Funktionalität myeloider Leukozyten unterstützt.

Innate immune activation via IL-1R or Toll-like receptors (TLR) contibutes to acute kidney injury but its role in tissue remodeling during chronic kidney disease is unclear. SIGIRR is an inhibitor of TLR-induced cytokine and chemokine expression in intrarenal immune cells, therefore, we hypothesized that Sigirr-deficiency would aggravate postobstructive renal fibrosis. The expression of TLRs as well as endogenous TLR agonists increased within six days after UUO in obstructed compared to unobstructed kidneys while SIGIRR itself was downregulated by day 10. However, lack of SIGIRR did not affect the intrarenal mRNA expression of proinflammatory and profibrotic mediators as well as the numbers of intrarenal macrophages and T cells or morphometric markers of tubular atrophy and interstitial fibrosis. Because SIGIRR is known to block TLR/IL-1R signaling at the level of the intracellular adaptor molecule MyD88 UUO experiments were also performed in mice deficient for either MyD88, TLR2 or TLR9. After UUO there was no significant change of tubular interstitial damage and interstitial fibrosis in neither of these mice compared to wildtype counterparts. Additional in-vitro studies with CD90+ renal fibroblasts revealed that TLR agonists induce the expression of IL-6 and MCP-1/CCL2 but not of TGF-β, collagen-1α or smooth muscle actin. Together, postobstructive renal interstitial fibrosis and tubular atrophy develop independent of SIGIRR, TLR2, TLR9, and MyD88. These data argue against a significant role of these molecules in renal fibrosis.

Thu, 16 Sep 2010 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/12138/ https://edoc.ub.uni-muenchen.de/12138/1/Kulkarni_Onkar.pdf Kulkarni, Onkar P ddc:610, ddc:600, Medizinisc

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) accompanied by demyelination and axonal loss. Only a minority of the demyelinated MS lesions gets remyelinated. In animal models, however, remyelination is the default program following immune-mediated or toxic demyelination. This thesis aims to find factors regulating remyelination in MS. The starting point was autoptic tissue from MS patients. First, different types of MS lesions were macrodissected namely, chronic inactive demyelinated lesions that had failed to remyelinate, lesions undergoing active demyelination and remyelinated lesions. Healthy white matter was used as control tissue. Gene expression profiles of these lesions were established using quantitative PCR low density arrays. Thereby the focus was on the extracellular matrix (ECM) and on factors known to regulate the biology of oligodendrocytes. ECM components can regulate oligodendrocyte differentiation and modify immune reactions in multiple ways, e.g., by sequestering or displaying growth factors and by directly interacting with immune cells and glial cells. The expression of 50 ECM components and 34 ECM degrading enzymes was measured by qPCR. COL1A1, COL3A1, COL5A1 and COL5A2 chains were strongly induced in active lesions and even more in chronic inactive lesions. These collagen polypeptide chains interact to form collagen types I, III and V, which are grouped as fibrillar collagens. Furthermore, two Small Leucine Rich Proteoglycans (SLRPs), biglycan and decorin, which can decorate fibrillar collagens, were also strongly induced. Immunostaining localized the fibrillar collagens, biglycan, and decorin around blood vessels. These ECM molecules were largely seen in the perivascular space closely associated with infiltrating immune cells forming a mesh between the endothelium and the astrocytic glia limitans. In active lesions collagen V was also seen in the heavily infiltrated brain parenchyma. Since these ECM molecules were found largely in the perivascular space close to immune cells and hardly in the surrounding parenchyma where oligodendrocyte differentiation takes place, the interaction of these ECM components with immune cells was further analysed. In vitro experiments revealed that the fibrillar collagens I and III inhibited the monocytic production of CCL2 (MCP-1), an inflammatory chemokine thought to be involved in the recruitment of immune cells to the inflamed brain. This suggests that the induced fibrillar collagens may contribute to the limitation of MS lesions expansion by inhibition of the CCL2 production by monocytes. The second set of analysed genes comprised 32 factors regulating survival, proliferation and/or differentiation of oligodendrocytes and 18 receptors of these genes. The key factors for oligodendrocyte differentiation (IGF1, IGF2 and CNTF) and oligodendrocyte proliferation (FGF2 and PDGFAA) were still present in demyelinated lesions, although their expression ratio was altered. The most striking result was the up-regulation of FGF9 in a subset of chronically demyelinated lesions, but in none of the remyelinated shadow plaques. The potential functional role of this observation was investigated by treating myelinating rat central nervous system cultures with exogenous FGF9. In this experimental setting, FGF9 inhibited the ability of mature oligodendrocytes to myelinate and ensheath axons. All these data suggests that the induction of FGF9 in some chronic MS lesions is one of the inhibitory mechanisms accounting for the failure of remyelination. Together, this thesis has two main findings: A) Fibrillar collagens, biglycan and decorin form a perivascular fibrosis and the fibrillar collagens I and III inhibit production of CCL2 by monocytes. Inhibition of CCL2 production by fibrillar collagens might contribute to lesion confinement. B) Expression profiles of remyelinated MS lesions were established for the first time and thereby, up-regulation of FGF9 in demyelinated, but not in remyelinated lesions was revealed. The inhibition of myelination in vitro by FGF9 suggests that this is one potential mechanism to explain why demyelinated lesions expressing higher FGF9 level fail to remyelinate.

Es ist bereits bekannt, dass akute Infektionen zur Verschlechterung einer vorbestehenden Glomerulonephritis führen können. Dies ist zum Beispiel bei der Lupusnephritis, der IgA-Nephropathie oder der renalen Vaskulitis der Fall (mesangioproliferative Glomerulonephritiden). Chronische virale Infektionen (z.B. Hepatitis C) können sogar eine de novo Glomerulonephritis auslösen. Hierbei handelt es sich um eine Immunkomplex-Glomerulonephritis, die durch die Bildung von Immunkomplexen aus eindringendem Antigen und daraufhin gebildetem Antikörper entsteht. Die Immunkomplexe werden über den Fc-Teil des Antikörpers erkannt. Ob die viralen Komponenten dieser Komplexe auch direkt erkannt werden und von welchen Zellen ist unbekannt. Neben der Bildung von Immunkomplexen spielt die Produktion von Interferonen eine wichtige Rolle bei der Entstehung von virusassoziierten Glomerulonephritiden. Die Aktivierung der systemischen antiviralen Immunität führt zur systemischen Interferonfreisetzung. Es wird angenommen, dass die meisten Zellen Typ I-Interferone produzieren können, wenn sie viral infiziert werden. So kann beispielsweise die TLR-3- vermittelte Erkennung viraler dsRNA in den Inselzellen des Pankreas über lokale IFN-a-Produktion eine autoimmune Inselzellzerstörung auslösen. Dahingegen ist unklar, ob lokal produzierte Typ I-Interferone zur Entstehung von irusassoziierten Glomerulonephritiden beitragen können. Wurde Mäusen virale dsRNA injiziert, gelangte diese zu den glomerulären Mesangialzellen. Mesangialzellen besitzen als einzigen nukleinsäurespezifischen Toll-like Rezeptor den TLR-3 und produzieren auf Stimulation durch virale dsRNA hin Interleukin-6 und CCL2. Ob dieser Effekt über den endosomalen TLR-3 oder über zytosolische dsRNA-Rezeptoren abläuft und ob Mesangialzellen überhaupt Interferone produzieren können, ist allerdings noch unklar. Unsere Hypothese ist, dass Mesangialzellen virale RNA sowohl TLR-abhängig als auch TLR-unabhängig erkennen können und dass die virale RNA daraufhin ein angeborenes antivirales Antwortprogramm, einschließlich der Produktion von Typ I-Interferonen, in glomerulären Mesangialzellen aktiviert.

Summary and hypothesis Role of pro-inflammatory chemokines in diabetic nephropathy Beyond hemodynamic and metabolic abnormalities associated with diabetes, the role of inflammation in development and progression of diabetic nephropathy is well accepted. Recruitment and activation of macrophages in different renal compartment is considered to be hallmark of all inflammation in diabetic nephropathy. Although recruitment of macrophages to the renal compartment has been extensively studied, the exact mechanisms involved are still to be explored. The chemokine-chemokine receptor interactions are implicated to be mainly responsible for trafficking and infiltration of different monocytes and macrophages. Contribution of macrophages to the development of DN can be addressed in either by inhibiting chemokines or chemokine receptor associated with diabetes. We hypothesized that inhibition of CCL2 may inhibit macrophages infiltrating into different compartments in kidney and inhibition started at earlier stage of disease progression may show more beneficial effects than CCL2 blockade at late stage of DN. To address the involvement of additional chemokine receptors we hypothesized that blocking CCR5 and CCR2 simultaneously might have some additive or synergistic effects. Role of homeostatic chemokines in diabetic nephropathy Homeostatic chemokies are mainly involved in hematopoeisis, immune cell survival and adaptive immune responses. CXCL12 attracted our attention as it is being extensively studied and reported to be responsible for different functions like stem cell survival and homing and trafficking to different compartments. The role of CXCL12 in diabetic nephropathy has not been explored yet. CXCL12 is constitutively expressed by different renal cells. It may contribute to tissue repair and inhibit disease progression by stem cell recruitment or may cause increased tissue fibrosis and aggravate the disease. We hypothesized that CXCL12 plays role in development and progression of diabetic nephropathy. In order to address this question we used CXCL12 blocker in a mouse model of diabetic nephropathy.

Mit der vorliegenden Studie wurde am Beispiel der diabetischen Nephropathie und der Nephropathie beim Alport-Syndrom die Rolle des Chemokins "macrophage chemoattractant protein-1" (Mcp-1) bei der Progression der chronischen Niereninsuffizienz untersucht, da es die damit assoziierte Rekrutierung von Makrophagen in die Niere vermittelt und in Korrelation zum Erkrankungsstadium verstärkt exprimiert bzw. verstärkt im Urin ausgeschieden wird. Mcp-1-defiziente diabetische Mäuse zeigen zudem eine verlangsamte Progression. Eine therapeutische Blockade von Mcp-1 sollte daher die Infiltration von Makrophagen reduzieren und mit geringerer Nierenschädigung einhergehen. Mcp-1 wurde bei uninephrektomierten db/db-Mäusen mit fortgeschrittener diabetischer Nephropathie und bei Kollagen-IV-a3-defizienten Mäusen mit autosomal-rezessiver Alport-Nephropathie mit einem neuartigen Antagonisten, dem Spiegelmer mNOX-E36-3’PEG blockiert. Bei uninephrektomierten db/db-Mäusen führte die achtwöchige Behandlung mit dem Spiegelmer zu einer Reduktion der glomerulären Makrophagen um 40 % und der tubulointerstitiellen Makrophagen um 53 %. Dies war assoziiert mit einer signifikanten Reduktion glomerulärer und tubulointerstitieller Schäden sowie einer Verbesserung der glomerulären Filtrationsrate (GFR). Daneben konnte die Expression von Mcp-1 und Ccr2 in der Niere signifikant reduziert werden. Bei Kollagen-defizienten Mäusen führte die sechs- bzw. dreiwöchige Behandlung zu einer Reduktion der glomerulären Makrophagen um 50 % und der tubulointerstitiellen Makrophagen um 30 %. Dies war jedoch weder mit einer Reduktion der Nierenschädigung oder der Expression von Mcp-1 und Ccr2, noch mit einer Verlängerung des Überlebens assoziiert. Zusammenfassend konnte gezeigt werden, dass die spät begonnene therapeutische Blockade von Mcp-1 durch das Spiegelmer mNOX-E36-3’PEG bei der db/db-Maus einen Schutz vor Glomerulosklerose bietet, die tubulointerstitielle Schädigung reduziert und die Nierenfunktion verbessert. Die Therapie mit anti-Mcp-1-Spiegelmeren könnte demnach das derzeitige Behandlungsregime der Diabetes-assoziierten chronischen Niereninsuffizienz um einen neuen Therapieansatz ergänzen und so die Progression verlangsamen. Beim Alport-Syndrom konnte die therapeutische Blockade von Mcp-1 durch das Spiegelmer mNOX-E36-3’PEG nicht vor Glomerulosklerose schützen, die tubulointerstitielle Schädigung nicht reduzieren, die Nierenfunktion nicht verbessern und das Überleben nicht verlängern. Ein Einfluss auf die Progression des Alport-Syndroms konnte nicht nachgewiesen werden. Die Therapie mit anti-Mcp-1-Spiegelmeren bietet demnach keine zusätzliche Behandlungsoption bei der hereditären Alport-Nephropathie.

Die vorliegende Studie trägt zum besseren Verständnis des breiten klinischen Spektrums und des Fehlens universeller Serum- Marker der infektionsassoziierten Krankheitsaktivität der Lupus- Nephritis und möglicherweise anderer Formen der Immunkomplexnephritis bei. Exogener Kontakt mit TLR 7- Liganden hat die Entwicklung der Lupus- Nephritis bei jungen, gesunden MRL- Wildtyp und MRLlpr/lpr Mäusen nicht getriggert und hatte keinen signifikanten Effekt auf die Krankheitsaktivität bei diesen jungen Mäusen. Bei alten Lupus- Mäusen führte eine ähnliche Exposition jedoch zu einem merklichen Anstieg der Serumspiegel proinflammatorischer Zytokine und von IFNα, sowie zu einer Infiltration der Nierenglomeruli 18 Wochen alter MRLlpr/lpr Mäuse mit Makrophagen und einer (nicht signifikanten) Erhöhung der Autoantikörperspiegel. Diese Daten unterstützen die Theorie, dass dem Toll- like Rezeptor 7 eine Rolle bei den Mechanismen, die das Fortschreiten der autoimmunen Gewebsschädigung in MRLlpr/lpr Mäusen fördern, zukommt. Basierend auf den Ergebnissen der funktionellen Rolle von TLR 7 in Lupus- Mäusen und in Primärzellen, die aus Lupusmäusen isoliert wurden, sahen wir in der TLR 7- Blockade ein mögliches neues Ziel, um die schädlichen Effekte des Signalings über Immunkomplexe und endogene Liganden zu begrenzen. Es zeigte sich, dass die Blockade von TLR 7 und TLR 7 + TLR 9 die Gewebsschäden in Nieren und Lunge signifikant reduzieren konnte. Eine TLR 7 Antagonisierung mit dem Oligodeoxyribonukleotid IRS661 senkte die Menge an Autoantikörpern (insbesondere anti- SM, anti- dsDNA, IgG2a, IgG2b), entzündlichen Zytokine und Chemokinen im Serum, glomerulären Ablagerungen von IgG2a und Komplementfaktor C3c deutlich. Die Hemmung von TLR 7 reduzierte ebenfalls die CC- Chemokin- gesteuerten Makrophagen- und T- Zell- Infiltrate in den Nieren. Dies zeigte sich durch erniedrigte Spiegel von Ccr2, Ccr5, Ccl2 und Ccl5 in den Nieren behandelter Tiere. Diese Ergebnisse unterstützen das Konzept, dass endogene TLR 7- Liganden zur Pathogenese der Autoantikörperproduktion und der autoimmun vermittelten Gewebsschädigung des SLE beitragen. Die TLR 7- Blockade könnte ein neues therapeutisches Konzept beim Lupus erythematodes sein.

The global burden of chronic kidney diseases remains an ongoing medical challenge. Therapies that can halt or reverse advanced renal injury are not yet available. Increasing numbers of patients progress to the end-stage renal failure and require renal replacement therapy, the latter being associated with significant mortality, a lower quality of life, and high costs for national health systems. Thus, new treatment strategies that slow down, halt or even revert progressive renal damage are requested. Chemokines and their receptors are involved in the pathogenesis of renal diseases. They mediate leukocytes and macrophages recruitment and activation during initiation as well as progression of renal inflammation. Infiltrating leukocytes are the major source for proinflammatory and profibrotic cytokines and are therefore critical for mediating fibroblast proliferation, differentiation into myofibroblasts, matrix production, and tubular atrophy. Recent advances in the understanding of the molecular mechanisms that regulate renal leukocyte recruitment suggest chemokines and chemokine receptors as novel targets for specific pharmacological intervention. The aim of the present thesis was to investigate the role of chemokine receptor CCR1 for the progression of chronic kidney diseases, e.g. Alport disease and diabetic nephropathy. Two different animal models were used: Col4A3-deficient mice and type 2 diabetic db/db mice with advanced diabetic nephropathy. We blocked CCR1 in Col4A3-deficient mice with BX417, a small molecule CCR1 antagonist, and BL5923, a novel orally available antagonist with a high specificity for human and murine CCR1 in uninephrectomized type 2 diabetic db/db mice, respectively. Treatment with BX471 (25mg/kg) from weeks 6 to 10 of life improved survival of COL4A3- deficient mice, characterized by glomerulosclerosis and subsequent progressive tubulointerstitial injury, leading to fatal end-stage renal disease (ESRD). Improvement was associated with less interstitial macrophages, apoptotic tubular epithelial cells, tubular atrophy, interstitial fibrosis, and less globally sclerotic glomeruli. BX471 reduced total renal Ccl5 mRNA expression by reducing the number of interstitial CCL5-positive cells in inflammatory cell infiltrates. Intravital microscopy of the cremaster muscle in male mice identified that BX471 or lack of CCR1 impaired leukocyte adhesion to activated vascular endothelium and transendothelial leukocyte migration, whereas leukocyte rolling and interstitial migration were not affected. Furthermore, in activated murine macrophages, BX471 completely blocked CCL3-induced CCL5 production. When CCR1 was blocked with BL5923 (60mg/kg, b.i.d), the interstitial recruitment of ex vivo labeled macrophages was markedly decreased in uninephrectomized male db/db mice with type 2 diabetes. Similarly, BL5923 orally administered from month 5 to 6 of life reduced the numbers of interstitial macrophages in uninephrectomized db/db mice. This was associated with reduced numbers of Ki-67 proliferating tubular epithelial and interstitial cells, tubular atrophy, and interstitial fibrosis in uninephrectomized db/db mice. Glomerular pathology and proteinuria were not affected by the CCR1 antagonist. BL5923 reduced renal mRNA expression of Ccl2, Ccr1, Ccr2, Ccr5, Tgf-β1, and collagen I-α1 when compared to untreated uninephrectomized male db/db mice of the same age. Thus, we identified a previously unrecognized role for CCR1-dependent recruitment of interstitial macrophages for the progression of chronic kidney disease in Alport disease and diabetic nephropathy. These data identify CCR1 as a potential therapeutic target for Alport disease and late stage diabetic nephropathy or other progressive nephropathies associated with interstitial macrophage infiltrates.

Thu, 15 Feb 2007 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/6556/ https://edoc.ub.uni-muenchen.de/6556/1/Helck_Andreas.pdf Helck, Andreas