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In this episode of the Epigenetics Podcast, we talked with Boyan Bonev from the HelmholtzZetrum in Munich about his work on neuroepigenetics, focusing on gene regulation, chromatin architecture, and primate epigenome evolution, This Episode focuses on Dr. Bonev's recent research, particularly focusing on how chromatin architecture and gene regulation influence neural cell identity and function. He discusses his work investigating transcriptional activity in relation to chromatin insulation, highlighting a critical finding that induced expression of genes does not necessarily lead to chromatin insulation—a point that complicates prior assumptions about the relationship between gene expression and chromatin organization. This study aimed to determine the causal versus correlative aspects of chromatin architecture in brain development and links it to developmental processes and neurodevelopmental disorders. Building on his findings in gene regulation, Dr. Bonev elaborates on a significant study he conducted in his own lab, where he mapped the regulatory landscape of neural differentiation in the mouse neocortex. Here, he employed cutting-edge single-cell sequencing methodologies to analyze intricate gene and enhancer interactions, revealing that selective enhancer-promoter interactions are primarily cell-type specific. This nuanced understanding aids in deciphering the complexities associated with gene expression as it relates to neural stem cells and differentiated neurons, emphasizing the importance of single-cell analyses over bulk sequencing methods. Moreover, Dr. Bonev reveals a novel methodology developed in his lab that allows for the simultaneous assessment of spatial genome organization, chromatin accessibility, and DNA methylation at high resolution. This advancement not only reduces costs but also enhances the potential to correlate higher-dimensional genomic data with specific biological questions, fostering a more integrative approach to understanding genetic regulation. The discussion then shifts focus towards Dr. Bonev's recent project profiling primate epigenome evolution, where he investigated the 3D genome organization, chromatin accessibility, and gene expression among iPSCs and neural stem cells from various species, including humans, chimpanzees, gorillas, and macaques. In this research, he identifies trends related to transcription factor evolution and chromatin modifications across species. The insights gleaned from this work underscore the evolutionary significance of structural variations in the 3D genome, pointing to a possible link between chromatin dynamics and the evolutionary development of the primate brain. References Bonev B, Mendelson Cohen N, Szabo Q, Fritsch L, Papadopoulos GL, Lubling Y, Xu X, Lv X, Hugnot JP, Tanay A, Cavalli G. Multiscale 3D Genome Rewiring during Mouse Neural Development. Cell. 2017 Oct 19;171(3):557-572.e24. doi: https://doi.org/10.1016/j.cell.2017.09.043. PMID: 29053968; PMCID: PMC5651218. Noack, F., Vangelisti, S., Raffl, G. et al. Multimodal profiling of the transcriptional regulatory landscape of the developing mouse cortex identifies Neurog2 as a key epigenome remodeler. Nat Neurosci 25, 154–167 (2022). https://doi.org/10.1038/s41593-021-01002-4 Noack F, Vangelisti S, Ditzer N, Chong F, Albert M, Bonev B. Joint epigenome profiling reveals cell-type-specific gene regulatory programmes in human cortical organoids. Nat Cell Biol. 2023 Dec;25(12):1873-1883. doi: 10.1038/s41556-023-01296-5. Epub 2023 Nov 23. PMID: 37996647; PMCID: PMC10709149. Related Episodes Characterization of Epigenetic States in the Oligodendrocyte Lineage (Gonçalo Castelo-Branco) Polycomb Proteins, Gene Regulation, and Genome Organization in Drosophila (Giacomo Cavalli) The Effect of lncRNAs on Chromatin and Gene Regulation (John Rinn) Contact Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Dr. Stefan Dillinger on LinkedIn Active Motif on LinkedIn Active Motif on Bluesky Email: podcast@activemotif.com
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.14.549055v1?rss=1 Authors: Samaddar, S., Srinivasan, B., Garg, K., Raj, N., Sultana, S., Mukherjee, U., Banerjee, D., Liau, W.-S., Palakodeti, D., Bredy, T. W., Banerjee, S. Abstract: Characterization of brain-enriched lncRNAs have predominantly been restricted to the nuclear compartment; with limited exploration of synaptic lncRNA functions. Our RNA-seq analysis of synaptoneurosomes identify 94 synaptically-enriched lncRNAs in the adult mouse hippocampus. Among these, we characterized the roles of Pantr1, Pvt1 and 2410006H16Rik (named SynLAMP) in glutamatergic synapse development, plasticity and memory. Pvt1 regulates dendritic arborization, spine morphology and glutamatergic synapse formation via a molecular framework of synaptogenic genes; as detected by RNA-seq analysis of the hippocampal trancriptome following Pvt1 knockdown. SynLAMP and Pantr1 modulate mEPSC amplitude and surface AMPA receptor distribution in mature synapses. We find activity-invoked redistribution of these synaptic lncRNAs and their concommitant reversible association with RNA binding proteins. The activity-dependent, transcript-specific synaptic localization of SynLAMP and Pantr1 indicate their synapse-centric function. SynLAMP specifically regulates basal and activity-invoked nascent translation in somato-dendritic compartments and its RNAi disrupts memory consolidation, underlining its input-specific role in synaptic translation. 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/2023.06.23.546336v1?rss=1 Authors: Badal, K. K., Sadhu, A., McCracken, C., Raveendra, B. L., Lozano-Villada, S., Shetty, A. C., Gillette, P., Zhao, Y., Stommes, D., Fieber, L. A., Schmale, M. C., Mahurkar, A., Hawkins, R. D., Puthanveettil, S. V. Abstract: Molecular mechanisms underlying aging associated impairments in learning and long-term memory storage are poorly understood. Here we leveraged the single identified motor neuron L7 in Aplysia, which mediates a form of non-associative learning, sensitization of the siphon-withdraw reflex, to assess the transcriptomic correlates of aging associated changes in learning. RNAseq analysis of the single L7 motor neuron isolated following short-term or long-term sensitization training of 8,10 and 12 months old Aplysia, corresponding to mature, late mature and senescent stages, has revealed progressive impairments in transcriptional plasticity during aging. Specifically, we observed modulation of the expression of multiple lncRNAs and mRNAs encoding transcription factors, regulators of translation, RNA methylation, and cytoskeletal rearrangements during learning and their deficits during aging. Our comparative gene expression analysis also revealed the recruitment of specific transcriptional changes in two other neurons, the motor neuron L11 and the giant cholinergic neuron R2 whose roles in long-term sensitization were previously not known. Taken together, our analyses establish cell type specific progressive impairments in the expression of learning- and memory-related components of the transcriptome during aging. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC
Synopsis: Samir Ounzain is the CEO and Co-Founder of HAYA Therapeutics, a precision medicines company developing RNA-guided programmable therapeutics targeting the regulatory genome for serious health conditions including fibrosis. Samir discusses the current landscape as it relates to precision medicine and genomic medicine and what his team is hoping to achieve over the next year. He also talks about the evolution of his approach to fundraising and shares his thoughts on applying machine learning and AI at the intersection of biology. Finally, with a distributed team in both the US and Switzerland, he discusses the challenges that come with that, and how he approaches team building. Biography: Samir Ounzain is a molecular biologist with over 15 years of experience exploring the dark matter of the genome and its roles in development and disease. Prior to founding HAYA Therapeutics, Samir was a Project Leader and Research Fellow at the Lausanne University Hospital (CHUV), where his research efforts directly led to the discovery of hundreds of novel heart-enriched lncRNAs, most notably the lncRNAs CARMEN, Meteor and Wisper.
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.05.03.539260v1?rss=1 Authors: Irwin, A. B., Martina, V., Sint Jago, S. C., Bahabry, R., Schreiber, A. M., Lubin, F. D. Abstract: Dysregulation of long non-coding RNAs (lncRNAs) have been associated with Alzheimer's disease (AD). However, the functional role of lncRNAs in AD remains unclear. Here, we report a crucial role for the lncRNA Neat1 in astrocyte dysfunction and memory deficits associated with AD. Transcriptomics analysis show abnormally high expression levels of NEAT1 in the brains of AD patients relative to aged-matched healthy controls, with the most significantly elevated levels in glial cells. In a human transgenic APP-J20 (J20) mouse model of AD, RNA-fluorescent in situ hybridization characterization of Neat1 expression in hippocampal astrocyte versus non-astrocyte cell populations revealed a significant increase in Neat1 expression in astrocytes of male, but not female, mice. This corresponded with increased seizure susceptibility in J20 male mice. Interestingly, Neat1 deficiency in the dCA1 in J20 male mice did not alter seizure threshold. Mechanistically, Neat1 deficiency in the dorsal area CA1 of the hippocampus (dCA1) J20 male mice significantly improved hippocampus-dependent memory. Neat1 deficiency also remarkably reduced astrocyte reactivity markers suggesting that Neat1 overexpression is associated with astrocyte dysfunction induced by hAPP/A{beta} in the J20 mice. Together, these findings indicate that abnormal Neat1 overexpression may contribute to memory deficits in the J20 AD model not through altered neuronal activity, but through astrocyte dysfunction. 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/2023.04.24.536852v1?rss=1 Authors: Zeidler, M., Tavares-Ferreira, D., Brougher, J., Price, T. J., Kress, M. Abstract: Non-coding RNAs (ncRNAs) play a critical role in regulating gene expression during development and in the pathogenesis of diseases. In particular, microRNAs have been extensively studied in the context of neurogenesis, the differentiation of pain sensing nociceptive neurons and the pathogenesis of pain disorder, however, little is known about the developmental signatures of other ncRNA species throughout sensory neuron differentiation. Moreover, there is currently no information available about the general expression signatures of ncRNAs in human dorsal root ganglia (DRGs) harboring the cell bodies of primary afferent nociceptors. To bridge this knowledge gap, we developed a comprehensive atlas of small ncRNA species signatures during the differentiation of human induced pluripotent stem cell (iPSC)-derived nociceptive neurons. By employing a combination of iPSC-derived sensory neuron and human DRG long and short RNA co-sequencing, we identified specific signatures that describe the developmental processes and the sig-natures of all currently known small ncRNA species in detail. Our analysis revealed that different ncRNA species, including tRNAs, snoRNAs, lncRNAs, and piRNAs, are associated with different stages of sensory neuron differentiation and maturation. We retrieved pro-nounced similarities in ncRNA expression between human DRG and late-stage iPSC-derived sensory neurons, which further supports the use of iPSC-derived sensory neurons to uncover functional and regulatory changes in ncRNAs and their suitability as a as a human model system to bridge the transla-tional gap between preclinical findings mostly from rodent models and our understanding of human disorders for the development of mechanism-based treatments. In summary, our findings provide important insights into the role of ncRNA species other than microRNAs in human nociceptors. The updated NOCICEPTRA2.0 Tool will be the first fully comprehensive searchable ncRNA database for human sensory neurons enabling researchers to investigate important hub ncRNA regulators in nociceptors in full detail. 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/2022.12.07.519382v1?rss=1 Authors: Fraile-Bethencourt, E., Khou, S., Wilson, R., Baris, A., Ruhl, R., Espinosa-Diez, C., Anand, S. Abstract: Endothelial cells are highly responsive to environmental changes that allow them to adapt to intrinsic and extrinsic stimuli and switch their transcriptome accordingly to go back to vascular homeostasis. Our previous data demonstrated that small non-coding-RNAs respond quickly to genotoxic stressors and determined endothelial cell fate and DNA damage response. To further understand the contribution of non-coding-RNAs, we profiled differentially expressed long non-coding RNAs in response to genotoxic stress and compared them to pro-angiogenic growth factor signaling. We identified the Maternally expressed gene 9 (MEG9) as a cytoprotective lncRNA in the endothelium. Gain and Loss-of-function studies indicate that MEG9 prevents endothelial cells from cell death, suggesting that MEG9 responses to genotoxic stress can be an adaptive and protective mechanism. Consistent with this phenotype, the knockdown of MEG9 decreases growth factor-dependent angiogenesis in a 3D fibrin gel angiogenesis assay. Deletion of the MEG9 ortholog, Mirg, in mice results in increased vascular leak in Matrigel plugs and a sex and age-dependent decrease in platelets. Mechanistically, we observed that both MEG9 knockdown in vitro and Mirg-deleted mice in vivo activated common pathways, including apoptosis, clotting, and inflammation. Indeed, the proinflammatory adhesion molecule ICAM1 was significantly increased in human and mouse endothelial cells in a MEG9-dependent manner, supporting the increased vascular permeability observed on MEG9 deficient cells. Taken together, our findings illustrate how genotoxic stress responses through dynamic modulation of lncRNAs, such as MEG9, trigger adaptive mechanisms to maintain endothelial function, while loss of these molecules contributes to maladaptive responses and endothelial cell dysfunction. 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/2022.11.30.518576v1?rss=1 Authors: Dueck, A., Althaus, L., Heise, K., Esfandyari, D., Bayguen, S., Brandes, R. P., Gagneur, J., Jae, N., Knolle, P., Leisegang, M. S., Maegdefessel, L., Meitinger, T., Petzold, N., Ramanujam, D., Sager, H., Schulz, C., Theodorakis, E., Uzonyi, A., Weinberger, T., Bader, M., Schmidt-Supprian, M., Engelhardt, S. Abstract: Cardiac resident macrophages (crMPs) were recently shown to exert pivotal functions in cardiac homeostasis and disease, but the underlying molecular mechanisms are largely unclear. Long non-coding RNAs (lncRNAs) are increasingly recognized as important regulatory molecules in a number of cell types, but neither the identity nor the molecular mechanisms of lncRNAs in crMPs are known. Here, we have employed deep RNA-seq and single cell RNA sequencing to resolve the crMP lncRNA landscape from healthy and diseased murine myocardium. CrMPs express previously unknown and highly cell type-specific lncRNAs, among which one lncRNA, termed Schlafenlnc, was particularly abundant and enriched in crMPs. We found Schlafenlnc to be necessary for migration-associated gene expression in macrophages in vitro and in vivo and essential for their adhesion and migration. Collectively, our data provide a basis to the systematic characterization of lncRNAs in crMPs and establish Schlafenlnc as a critical regulator of macrophage migratory functions. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC
In this episode of the Epigenetics Podcast, we caught up with John Rinn from the University of Colorado in Boulder to talk about his work on the role of lncRNAs in gene expression and nuclear organization. The Rinn Lab pioneered the approach of screening the human genome for long noncoding RNAs (lncRNAs). More recently, the lab has shifted focus from measuring the number of lncRNAs to finding lncRNAs that have a distinct biological function in human health and disease. One example of such a lncRNA is FIRRE, which is present in all animals, however the sequence is not conserved, except for in primates. FIRRE contains many interesting features, such as repeat sequences and CTCF binding sites. In absence of FIRRE, defects in the immune system can be observed and also some brain defects may also be observed. References Carter, T., Singh, M., Dumbovic, G., Chobirko, J. D., Rinn, J. L., & Feschotte, C. (2022). Mosaic cis-regulatory evolution drives transcriptional partitioning of HERVH endogenous retrovirus in the human embryo. eLife, 11, e76257. Advance online publication. https://doi.org/10.7554/eLife.76257 Long, Y., Hwang, T., Gooding, A. R., Goodrich, K. J., Rinn, J. L., & Cech, T. R. (2020). RNA is essential for PRC2 chromatin occupancy and function in human pluripotent stem cells. Nature Genetics, 52(9), 931–938. https://doi.org/10.1038/s41588-020-0662-x Kelley, D., & Rinn, J. (2012). Transposable elements reveal a stem cell-specific class of long noncoding RNAs. Genome biology, 13(11), R107. https://doi.org/10.1186/gb-2012-13-11-r107 Khalil, A. M., Guttman, M., Huarte, M., Garber, M., Raj, A., Rivea Morales, D., Thomas, K., Presser, A., Bernstein, B. E., van Oudenaarden, A., Regev, A., Lander, E. S., & Rinn, J. L. (2009). Many human large intergenic noncoding RNAs associate with chromatin-modifying complexes and affect gene expression. Proceedings of the National Academy of Sciences, 106(28), 11667–11672. https://doi.org/10.1073/pnas.0904715106 Guttman, M., Amit, I., Garber, M., French, C., Lin, M. F., Feldser, D., Huarte, M., Zuk, O., Carey, B. W., Cassady, J. P., Cabili, M. N., Jaenisch, R., Mikkelsen, T. S., Jacks, T., Hacohen, N., Bernstein, B. E., Kellis, M., Regev, A., Rinn, J. L., & Lander, E. S. (2009). Chromatin signature reveals over a thousand highly conserved large non-coding RNAs in mammals. Nature, 458(7235), 223–227. https://doi.org/10.1038/nature07672 Related Episodes The Role of lncRNAs in Tumor Growth and Treatment (Sarah Diermeier) The Role of Small RNAs in Transgenerational Inheritance in C. elegans (Oded Rechavi) Chromatin Structure and Dynamics at Ribosomal RNA Genes (Tom Moss) Contact Active Motif on Twitter Epigenetics Podcast on Twitter Active Motif on LinkedIn Active Motif on Facebook Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we caught up with Manel Esteller, Director of the Josep Carreras Leukemia Research Institute to talk about his work on Epigenetics and Epitranscriptomics in Cancer. The focus of Manel Esteller's research career and the focus of his current team is to characterize the epigenome and epitranscriptome of cancer cells in comparison to healthy cells, and their interplay. Ultimately, their goal is to use this knowledge to develop new therapies for cancer. Key achievements from the Esteller lab began with the discovery of the first miRNA that undergoes specific cancer-methylation associated silencing. The team further identified many more miRNAs that also play a role in cancer. Next to miRNAs, Manel Esteller studied the influence of lncRNAs, enhancers and DNA methylation on cancer development and progression, insights that may be used to develop cancer biomarkers and potential treatments. References Guil, S., Soler, M., Portela, A., Carrère, J., Fonalleras, E., Gómez, A., Villanueva, A., & Esteller, M. (2012). Intronic RNAs mediate EZH2 regulation of epigenetic targets. Nature Structural & Molecular Biology, 19(7), 664–670. https://doi.org/10.1038/nsmb.2315 Vizoso, M., Ferreira, H. J., Lopez-Serra, P., Carmona, F. J., Martínez-Cardús, A., Girotti, M. R., Villanueva, A., Guil, S., Moutinho, C., Liz, J., Portela, A., Heyn, H., Moran, S., Vidal, A., Martinez-Iniesta, M., Manzano, J. L., Fernandez-Figueras, M. T., Elez, E., Muñoz-Couselo, E., … Esteller, M. (2015). Epigenetic activation of a cryptic TBC1D16 transcript enhances melanoma progression by targeting EGFR. Nature Medicine, 21(7), 741–750. https://doi.org/10.1038/nm.3863 Agrelo, R., Cheng, W.-H., Setien, F., Ropero, S., Espada, J., Fraga, M. F., Herranz, M., Paz, M. F., Sanchez-Cespedes, M., Artiga, M. J., Guerrero, D., Castells, A., von Kobbe, C., Bohr, V. A., & Esteller, M. (2006). Epigenetic inactivation of the premature aging Werner syndrome gene in human cancer. Proceedings of the National Academy of Sciences of the United States of America, 103(23), 8822–8827. https://doi.org/10.1073/pnas.0600645103 Lopez-Serra, P., Marcilla, M., Villanueva, A., Ramos-Fernandez, A., Palau, A., Leal, L., Wahi, J. E., Setien-Baranda, F., Szczesna, K., Moutinho, C., Martinez-Cardus, A., Heyn, H., Sandoval, J., Puertas, S., Vidal, A., Sanjuan, X., Martinez-Balibrea, E., Viñals, F., Perales, J. C., … Esteller, M. (2014). A DERL3-associated defect in the degradation of SLC2A1 mediates the Warburg effect. Nature Communications, 5, 3608. https://doi.org/10.1038/ncomms4608 Rosselló-Tortella, M., Llinàs-Arias, P., Sakaguchi, Y., Miyauchi, K., Davalos, V., Setien, F., Calleja-Cervantes, M. E., Piñeyro, D., Martínez-Gómez, J., Guil, S., Joshi, R., Villanueva, A., Suzuki, T., & Esteller, M. (2020). Epigenetic loss of the transfer RNA-modifying enzyme TYW2 induces ribosome frameshifts in colon cancer. Proceedings of the National Academy of Sciences of the United States of America, 117(34), 20785–20793. https://doi.org/10.1073/pnas.2003358117 Castro de Moura, M., Davalos, V., Planas-Serra, L., Alvarez-Errico, D., Arribas, C., Ruiz, M., Aguilera-Albesa, S., Troya, J., Valencia-Ramos, J., Vélez-Santamaria, V., Rodríguez-Palmero, A., Villar-Garcia, J., Horcajada, J. P., Albu, S., Casasnovas, C., Rull, A., Reverte, L., Dietl, B., Dalmau, D., … Esteller, M. (2021). Epigenome-wide association study of COVID-19 severity with respiratory failure. EBioMedicine, 66, 103339. https://doi.org/10.1016/j.ebiom.2021.103339 Related Episodes CpG Islands, DNA Methylation, and Disease (Sir Adrian Bird) Targeting COMPASS to Cure Childhood Leukemia (Ali Shilatifard) Cancer and Epigenetics (David Jones) Contact Active Motif on Twitter Epigenetics Podcast on Twitter Active Motif on LinkedIn Active Motif on Facebook Email: podcast@activemotif.com
Please join Guest Host Mercedes Carnethon along with first author Connie Hess and Guest Editor Gregory Lip as they discuss the article "Reduction in Acute Limb Ischemia With Rivaroxaban Versus Placebo in Peripheral Artery Disease After Lower Extremity Revascularization: Insights From VOYAGER PAD." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, associate editor, director of the Poly Heart Center at VCU Health in Richmond, Virginia. Dr. Carolyn Lam: Greg, our feature discussion is on a really important topic, peripheral artery disease. So important, so rampant, not talked about enough. And it's really insights from the VOYAGER-PAD trial telling us about the reduction in acute limb ischemia with Rivaroxaban versus placebo in peripheral artery disease after lower extremity revascularization. But before we get into all that, I want you to get your coffee while I tell you about my picks of today's issue. Should I start? Dr. Greg Hundley: Very good. Dr. Carolyn Lam: Okay. So the first paper deals with the residual ischemic risk following coronary artery bypass grafting surgery. We know that despite advances, patients following CABG still have significant risk. So this paper refers to a subgroup of patients from the REDUCE-IT trial with a history of CABG, which was analyzed to evaluate the efficacy of icosapent ethyl treatment in the reduction of cardiovascular events in this high risk patient population. Now, as a reminder, the REDUCE-IT trial was a multicenter, placebo controlled, double blind trial, where statin treated patients with controlled LDL cholesterol and mild to moderate hypertriglyceridemia were randomized to four grams daily of icosapent ethyl or placebo. They experienced a 25% reduction in risk of a primary efficacy endpoint, which was cardiovascular death, MI, stroke, coronary revascularization, or hospitalization for unstable angina. Now the current report tells us about the subgroup of patients from the trial with a history of CABG. Dr. Greg Hundley: Ah, Carolyn. So what did they find in this subgroup of patients? Dr. Carolyn Lam: So of the 8,179 patients randomized in REDUCE-IT, 22.5% had a history of CABG with 897 patients randomized to icosapent ethyl and 940 to placebo. Baseline characteristics were similar between the treatment groups and randomization to icosapent ethyl was associated with a significant reduction in the primary endpoint, as well as in key secondary endpoint and in total ischemic events compared to placebo. This yielded an absolute risk reduction of 6.2% in first events with a number needed to treat of 16 over a median follow up time of 4.8 years. So, Greg, I think you'll agree, icosapent ethyl may be an important pharmaco-therapeutic option to consider in eligible patients with a history of coronary artery bypass grafting surgery. Dr. Greg Hundley: Very nice, Carolyn. What an excellent summary. So Carolyn, for my first paper... And this study comes to us from Professor Judith Haendeler from the Leibniz Research Institute for Environmental Medicine. So Carolyn, this is a new type of quiz question. And as you listen to the presentation, help us predict the clinical implications. Okay, here we go. Dr. Greg Hundley: All right. So Carolyn, telomerase, also called terminal transferase, is a ribonuclear protein that adds a species dependent telomere repeat sequence to the three prime end of telomeres. And Carolyn, just to refresh our memories, a telomere is a region of repetitive sequences at each end of the chromosomes of most eukaryotes. And telomerase was discovered interestingly by Carol Greider and Elizabeth Blackburn in 1984. And together with some others, including Jack Szostak, they were awarded the 2009 Nobel Prize in physiology and medicine for discovery. Dr. Greg Hundley: So Carolyn, telomerase is active in gamuts and most cancer cells, but is normally absent from or at very low levels in most somatic cells. And the catalytic subunit of telomerase called telomerase reverse transcriptase or trt has protective functions in the cardiovascular system, particularly in regard to ischemia reperfusion injury. And interestingly trt or telomerase reverse transcriptase is not present in the nucleus, but also in mitochondria. However, for us in cardiovascular medicine, it is unclear whether nuclear or mitochondrial trt is responsible for the observed protection. Dr. Carolyn Lam: Wow, fascinating. So what did today's paper find? Dr. Greg Hundley: Right, Carolyn. So it was mitochondrial, but not nuclear telomerase reverse transcriptase that was found critical for mitochondrial respiration during ischemia reperfusion injury. And mitochondrial telomerase reverse transcriptase improves complex 1 subunit composition. And trt is present in human heart mitochondria and remote ischemic preconditioning increases its level in these organelles. Also, Carolyn TA65 was found to have comparable effects ex vivo and improved migratory capacity of endothelial cells and myofibroblast differentiation. So Carolyn, with this summary, can you help speculate on the clinical implications of this paper? Dr. Carolyn Lam: Oh, Greg. You set it up so nicely. So I would speculate that the clinical implications are that an increase in the mitochondrial telomerase reverse transcriptase or trt would be able to help with cardioprotection in ischaemic reperfusion injury, or at least that's what we hope and that's where we should be going with this. Am I right? Dr. Greg Hundley: Absolutely, Carolyn. So in the future, this research showing that trt and cardioprotection... Maybe we increase this and it could serve as a therapeutic strategy. Excellent job, Carolyn. Dr. Carolyn Lam: Thank you, Greg. All right. My next paper is a preclinical paper. I will spare you of difficult quizzes and maybe... This is just so neat. Let me tell you about it. So the study really provides novel insights into the mechanisms underlying smooth muscle cell phenotypic modulation that contributes to the development of vascular diseases like renal atherosclerosis and restenosis after angioplasty. So very important. Dr. Jiliang Zhou from Medical College of Georgia and colleagues basically used an in silico approach to probe unbiased, proprietary, and diverse, publicly available bulk RNA-Seq and scRNA-Seq datasets to search for smooth muscle cell specific long non-coding RNAs or lncRNAs. Dr. Carolyn Lam: The search ended up identifying CARMN, which stands for cardiac mesoderm enhancer-associated non-coding RNA, CARMN. As a highly abundant, highly conserved smooth muscle cell specific lncRNA, CARMN was recently reported to play roles in cardiac differentiation and was initially annotated as a host lncRNA for the microRNA, the MIR143145 cluster, which is the best characterized microRNAs in regulating smooth muscle cell differentiation and phenotypical modulation. Dr. Carolyn Lam: But in the current study, the authors confirmed the expression specificity of CARMN using a novel GFP knock-in reporter mouse model, and discovered that CARMN is downregulated in various vascular diseases. They further found that CARMN is critical for maintaining vascular smooth muscle cell contractile phenotype, both in vitro and in vivo by directly binding to the smooth muscle cell specific transcriptional cofactor known as myocardit. Dr. Greg Hundley: Okay. Carolyn, what a beautiful summary here. So what's the take home message here? Dr. Carolyn Lam: So these findings collectively suggest that CARMN is a key regulator of vascular smooth muscle cell phenotype, and therefore represents a potential therapeutic target for the treatment of smooth muscle cell related proliferative diseases. Dr. Carolyn Lam: Well, Greg, thanks for letting me to tell you about that one. But let me tell you also about other papers in today's issue. There's an exchange of letters between Dr's Lee and Chew on high rates of coronary events in the rapid troponin T0 one hour protocol. Is it a reality or illusion? There's an ECG Challenge by Dr. Liu on “Acute Inferior Wall Myocardial Infarction. What is the Culprit Artery? In Cardiology News, Bridget Kuehn writes on persistent heart effects of COVID-19 and how that emphasizes the need for prevention. Dr. Greg Hundley: Very nice, Carolyn. Well, I've got a Research Letter to tell you about from Professor Huang, entitled “High Prevalence of Unrecognized Congenital Heart Disease in School-Age Children in Rural China: A Population-Based Echocardiographic Screening Study.” Well, Carolyn, what a fantastic issue. And how about we get onto that feature discussion now and learn more out lower extremity revascularization and insights from the VOYAGER-PAD study? Dr. Carolyn Lam: Let's go, Greg. Dr. Mercedes Carnethon: Good morning, everyone. Welcome to this episode of Circulation on the Run podcast. I'm Mercedes Carnethon, Professor and Vice Chair of Preventive Medicine at the Northwestern University Feinberg School of Medicine and associate editor of the journal. Really excited today to hear from one of our authors of a particularly interesting piece that we'd like to discuss today about peripheral artery disease after lower extremity revascularization. Dr. Mercedes Carnethon: And we have with us today, the lead author, Dr. Connie Hess from the division of cardiology at the University of Colorado School of Medicine in Aurora. And we have Dr. Gregory Lip with us. So welcome to the both of you. Professor Gregory Lip: Hello there. Dr. Connie Hess: Thank you for having me. Dr. Mercedes Carnethon: Thank you both for joining us. This is really exciting. I know that when I read this piece, I was really excited to think about the implications that these study findings from this clinical trial will have for a very important clinical problem of peripheral arterial disease and those complications. So, Connie, would you be willing to start by telling us a little bit about what you found in this study? Dr. Connie Hess: Yeah, absolutely. I think maybe a good place to start first is, if that's okay, is just a little bit of the background and why we looked at this and thought to look at this. I think as you're both probably aware, peripheral artery disease is a very highly prevalent condition. It affects a lot of people, but there's not a lot of awareness about it. It's in some ways the forgotten manifestation of atherosclerosis. And so acute limb ischemia in particular is a very feared complication of peripheral artery disease. And unlike things like ST elevation, myocardial infarction, and stroke about which patients and providers have a lot of knowledge and understanding, many people don't know about acute limb ischemia. And in particular ALI, acute limb ischemia, is a complication of peripheral revascularization that many of us as proceduralists are very concerned about. Dr. Connie Hess: And so what we wanted to do was use this very unique clinical trial and dataset to look at acute limb ischemia, to describe it, to better understand it, especially after a peripheral revascularization. And then also to look at the effect of Rivaroxaban plus aspirin versus aspirin alone on this feared outcome. We're lacking therapies to effectively prevent ALI. Dr. Connie Hess: And so if I just briefly review the trial, VOYAGER-PAD randomized 6,564 patients undergoing peripheral revascularization, both surgical or endovascular to Rivaroxaban, 2.5 milligrams twice daily versus placebo on top of aspirin. And then providers could use prochidagril for up to six months per their discretion. Now, the primary outcome for VOYAGER-PAD was very unique. This was a five point composite that looked at acute limb ischemia, major amputation of vascular etiology, myocardial infarction, ischemic stroke, or cardiovascular death. Dr. Connie Hess: And so in this trial in the primary results, Rivaroxaban plus aspirin versus aspirin alone was highly effective in reducing the primary endpoint, that five point composite I just described. And so we were excited to look specifically at the effect of this combination therapy on acute limb ischemia alone. What we found to begin with, I think in terms of describing acute limb ischemia is important. So the three year cumulative incidence in the patients assigned a placebo was about 8% for ALI. So this is not an uncommon problem. And in fact, we found that there was incidents of ALI occurring quite early after the procedure and that the risk persisted, even three years out. Dr. Connie Hess: And Rivaroxaban plus aspirin versus aspirin alone was very effective in reducing ALI by about 33%. Beyond that, we also looked at ALI in terms of severity of these complications. And we found that about a third of patients had a very severe ALI event that we defined as ALI followed by death, major amputation, or requiring a prolonged hospitalization with time in the intensive care unit. And for those patients, Rivaroxaban plus aspirin was even more effective with almost a 55% reduction. Dr. Connie Hess: Lastly, I think we also looked at just the patients who are at risk for ALI after peripheral revascularization. And we did identify some patient and procedural factors that might help us identify these patients. For example, having a prior lower extremity revascularization, having more severe PAD as indicated by a low ankle brachial index, undergoing surgical revascularization, and having longer target lesions. So I think we were able to describe ALI in a way that some other trials and datasets have not been able to do. And then also beyond that to provide some evidence for effective therapy to prevent this complication. Dr. Mercedes Carnethon: All of that is so exciting. And for somebody coming to this outside of the initial field, I can certainly see a lot of innovations that you describe in what you've done and the importance to the population of people who experience this very debilitating illness. So it's really wonderful to see this in print. So tell me, Greg, what excited you as the editor about this particular paper? So what made it really stand out in your mind? Professor Gregory Lip: Thanks, Mercedes. And firstly, congratulations to Dr. Hess for a really nice paper. And I think that it's really important because many cardiologists tend to neglect looking at and managing peripheral artery disease, especially with the medical therapies. And I think VOYAGER-PAD was an important advancement of how we can have... You could say, dual blockade, both with low dose anticoagulation plus antiplatelets should improve the outcomes. Professor Gregory Lip: So I think it really brings to the forefront how we should optimize medical therapy and peripheral disease. It's not simply a matter of surgery or just intervention with stenting. And I think maybe the other important aspects in regard to this study, this trial is when you combine an antiplatelet with an anticoagulant, it's worth flagging up the potential for added risk of bleeding. And it's therefore the fact that your analysis included to identify the patients at high risk of acute limb ischemia, then we will actually facilitate risk stratification so that we can perhaps target the very high risk patients where that balance in terms of the net benefit for the combination therapy compared to aspirin alone would be there because you're balancing the thrombotic and limb ischemic outcome versus the potential for bleeding. Professor Gregory Lip: We are also using of course, in VOYAGER-PAD low dose Rivaroxaban, which is not the stroke prevention dose of Rivaroxaban in everyday clinical practice. And that's worth emphasizing. So we translate peripheral disease dosages or regimes versus what we see in other prothrombotic situations like atrial fibrillation, which leads to stroke. And that's probably worth emphasizing. And I think really what is most important is that we can hopefully identify the high risk subset of patients with peripheral artery disease at risk of acute limb ischemia, where they're going to particularly benefit from combination therapy. So an important advance for medical therapy for peripheral disease. So congratulations on this paper as well. Dr. Mercedes Carnethon: Yeah. I really echo that. One of the things that when we write original research papers, we are always encouraged not to speculate beyond the data that we're presenting. But one of the values of this podcast is that we get a chance to really needle the authors and challenge them to speculate about what does this mean? What does this mean for the field? And Connie in particular, what do you think the next steps are for patients and providers based on what you found today in this excellent study? Dr. Connie Hess: Mercedes, that's a great question. Certainly we always want to know what next? What are the implications of these findings? And so to me, I echo both of you. I'm personally very excited as someone in the field. And as a proceduralist, I'm very excited that for the first time, we actually have data to support a medical therapy post intervention. Although there's a lot of use of things like dual antiplatelet therapy and even anticoagulation, there's not a lot of data to support it after peripheral revascularization. So this really is the first large scale, high quality data to support a strategy. And so I do think that this is something that we should adopt. Dr. Connie Hess: I think what I didn't mention before is that actually, when you look at the cumulative incidence curves for ALI in the Rivaroxaban versus placebo groups, not only do you see that there is early risk for ALI after the procedure... And typically we think of this as potentially technical failure that we can't modify, but you saw a very early benefit for Rivaroxaban plus aspirin versus aspirin alone here, suggesting that the sooner you start, the better. Of course, it has to be when it's safe from a bleeding perspective and when the proceduralist feels comfortable with this. But I do think that the implications are that we should... We proceduralists, especially in this population and as professor Lip mentioned the high risk patients in particular, should be starting this therapy as soon as we feel safe. And so I think the data are there. The next step to me is really increasing awareness, in particular among providers who are treating these patients, but even among our other colleagues or cardiovascular colleagues who may not treat these peripheral artery disease patients primarily, but do see them in their clinic. Dr. Connie Hess: A lot of them have cardiovascular disease and other cardiovascular problems, but to increase awareness that this dual pathway inhibition with low dose factor 10, anticoagulation inhibition and low antiplatelet therapy is a viable and favorable combination and to continue this so that when they see this, they're not surprised and not questioning whether to stop it. Dr. Connie Hess: I think also of course now that we are getting more data to understand how morbid and bad ALI is, I do think we also need to educate patients. You both probably recall all the tremendous efforts that were made to increase awareness in the patient population about myocardial infarction and stroke. You have all those campaigns and understanding the importance of timely intervention and reperfusion. I think that actually should be done for acute limb ischemia as well. We need to have providers aware about this complication and understanding emergent treatment. We also need patients to understand it so they can come in sooner so that they're not having delayed presentation for which primary amputation is the only treatment option. So I think there's a lot of work to be done, but certainly very excited that we have a better understanding of ALI as well as preventive therapy. Dr. Mercedes Carnethon: I really appreciate that final word. And I really can't think of a better way to wrap up than the final words that you provided, Connie. Both the context that you provided around this piece and your thoughts as well, Greg, about what makes it innovative and exciting for our readership at Circulation are really invaluable. So I just really want to thank you for joining us as an author and thank you for selecting this, Greg. This is a really great piece. I've learned a good deal. Dr. Mercedes Carnethon: This is me, Mercedes Carnethon, wrapping up this addition of Circulation on the Run, following an outstanding discussion with Dr. Connie Hess from the University of Colorado and Greg Lip, the handling editor for the piece. Dr. Greg Hundley: 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 of the American Heart Association. For more, visit ahajournals.org.
Please join author Maria Nunes and Associate Editor Ntobeko Ntusi as they discuss the article “Incidence and Predictors of Progression to Chaga Cardiomyopathy: Long-Term Follow-Up of Trypanosoma cruzi-Seropositive Individuals.” Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, Associate Editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well Carolyn, this feature this week, we're going to talk about Chagas disease and we have some really important long-term, really for the first time, observational data and a cohort that's been followed in Brazil. And it's just a wonderful discussion from a team that's been working very hard in this area over an extended period of time. But before we get to that, how about we grab a cup of coffee and get started on some of the other articles in this issue? Would you like to go first? Dr. Carolyn Lam: I would. And with your coffee, I would like to tell you about non-combustible nicotine or tobacco products. Fancy a smoke with your coffee? Well, you know that those are novel forms of nicotine consumption composed of things like nicotine vaping products that vaporize the nicotine-containing fluids and heated tobacco products that really heat the tobacco products without combustion. Now, these have recently gained popularity because they're portrayed as being safer modes of smoking compared with the traditional combustible cigarettes. However, their associations with subsequent cardiovascular disease risks are still unclear. So Greg, here's today's quiz. Gosh, I miss our quizzes. What do you think? Are they safer or are they not? Dr. Greg Hundley: Oh, Carolyn, you're catching me on this and I never know which way to go, but I'm going to guess not. How about you tell us? Dr. Carolyn Lam: Well, the paper will tell us, and this is from co-corresponding authors Dr. Lee from Seoul National University Bundang Hospital and Dr. Park from Seoul National University College of Medicine and their colleagues. And they basically studied more than 5,000,000 adult men who underwent health screening examinations during both a first and second phase of health screening periods from the Korean National Health Insurance Service Database spanning 2014 to 2018. Initial combustible cigarette smokers who subsequently quit that cigarette smoking and converted to a non-combustible nicotine or tobacco product use was associated with a lower incident cardiovascular disease risk compared to those who continue the combustible cigarette use. However, compared with combustible cigarette quitting without using these non-combustible substitutes, those who ceased smoking but continued with the non-combustible products was associated with a higher cardiovascular disease risk. So the take home message is although the non-combustible nicotine or tobacco products may be associated with a lower cardiovascular disease risk compared with continued combustible cigarette smoking, those who quit without using these substitutes may benefit the most in reducing the risk of developing future cardiovascular disease events. And this is discussed in a wonderful editorial by Dr. Auer, Diethelm and Berthet. Dr. Greg Hundley: Very nice, Carolyn. Great presentation and really new information in this space. Well, my paper comes from the world of preclinical science and it involves long noncoding RNAs. And Carolyn, they are important regulators of biological processes involved in vascular tissue homeostasis and cardiovascular disease development. And so, the current study, led by Professor Lars Maegdefessel from Karolinska Institute, assessed the functional contribution of the long noncoding RNAs myocardial infarction associated transcripts and their relationship to atherosclerosis and carotid artery disease. Dr. Carolyn Lam: Hmm, interesting. They are the rage, these lncRNAs. So what did they find, Greg? Dr. Greg Hundley: Right, Carolyn. So long noncoding RNAs possess key regulatory functions directly interacting and mediating expression and functionality of proteins, other RNAs, as well as DNA. Next, the long noncoding RNA myocardial infarction associated transcript plays a key role during atherosclerotic plaque development and lesion destabilization. Its expression becomes highly increased in high risk patients with vulnerable plaques. And so, Carolyn, the take home therapeutic targeting of the long noncoding RNA myocardial infarction associated transcript, using antisense oligonucleotides, well that offers novel treatment options for patients with advanced atherosclerosis in the carotid arteries that are at risk of stroke. Dr. Carolyn Lam: Oh, very interesting. So from the preclinical world back to the clinical world with an important clinical trial. Now, we know that percutaneous closure of the left atrial appendage is an alternative to chronic oral anticoagulation to reduce stroke risk in patients with nonvalvular atrial fibrillation. The Amplatzer Amulet Left Atrial Appendage Occluder IDE trial, called the Amulet IDE trial, was designed to evaluate the safety and effectiveness of the dual seal mechanism of the Amulet left atrial appendage occluder compared with the WATCHMAN device. And here, 1,878 patients with nonvalvular atrial fibrillation at increased risk of stroke were randomly assigned to undergo percutaneous implantation of a left atrial appendage occluder with the Amulet occluder or a WATCHMAN device. And the primary end points included safety, which was a composite of procedure-related complications all cause death or major bleeding at 12 months, and effectiveness, which was a composite of ischemic stroke or systemic embolism at 18 months. They also looked at the rate of left atrial appendage occlusion at 45 days. And this paper is from Dr. Lakkireddy and colleagues from Kansas City Heart Rhythm Institute. Dr. Greg Hundley: Well Carolyn, these devices, they are really being heavily tested in patients with atrial fibrillation. So what did they find? Dr. Carolyn Lam: The Amulet occluder was non-inferior with respect to safety and effectiveness compared to the WATCHMAN device, and superior with respect to left atrial appendage occlusion; however, procedure-related complications were higher with the Amulet occluder, largely related, perhaps, to more frequent pericardial effusion and device embolization. And the authors noted that the procedure-related complications decreased with operator experience; however, I think all of this still needs to be further investigated. Well, those were really nice original papers, but let's also discuss what else there is in today's issue. There is an exchange of letters between Drs. Mueller and Allen regarding the article “Diagnostic Performance of High Sensitivity Cardiac Troponin T Strategies and Clinical Variables in a Multisite U.S. Cohort.” There's a perspective piece by Dr. Olson, “Toward CRISPR Therapies for Cardiomyopathies.” Dr. Greg Hundley: And Carolyn, I've got a research letter from Professor Layland entitled “Colchicine in Patients with Acute Coronary Syndromes: Two Year Follow Up of the Australian COPS Randomized Clinical Trial.” Well, what a great set of papers that we've discussed. Now, let's get on to that feature discussion and learn a little bit more about the longitudinal history and progression of cardiovascular disease and patients with Chagas disease. Dr. Carolyn Lam: Yay. Let's go, Greg. Dr. Greg Hundley: Well, listeners, we are here for our feature discussion today and a very exciting one we have, pertaining to Chagas disease. And we have with us today Dr. Maria Nunes from Belo Horizonte, Brazil, and also one of our Associate Editors, Dr. Ntobeko Ntusi from Cape Town, South Africa. Welcome to you both. And Maria, we'll start with you. Could you describe for us some of the background information pertaining to your study and what was the hypothesis that you wanted to address? Dr. Maria Nunes: Yes, thank you for these opportunities. My main hypothesis is that Chagas disease is the major cause of dilated cardiomyopathy in endemic areas. So we selected patients without cardiomyopathy at baseline to see if the Trypanosoma cruzi seropositivity is a predictor of further developing of cardiomyopathy. Dr. Greg Hundley: Very nice. And so tell us, how did you construct this study? What was your design? And then also, maybe describe for us how you selected the participants for this study. Dr. Maria Nunes: We selected the participants from two blood donor centers. One in Sao Paulo and one in Montes Claros, which is north of Minas Gerais State. We select blood donors because it's the way that we have Chagas disease's screening tests. And in asymptomatic patients, usually at the hospital, patients comes to us with heart failure or a kind of symptoms related to Chagas disease. Our main goals in this study is to select healthy participants based on the screen test of Trypanosoma cruzi. So the population was blood donors selected from two centers. Dr. Greg Hundley: Very good. And then again, your study design. So did you follow these two groups of individuals longitudinally over time, and for how long? Dr. Maria Nunes: Yes, we have different visits of this study with the patients initially was selected at first in 1996 and 2002. At this time, they don't have cardiovascular exams. And our study actually is starting 2008 to 2010, and we select all these patients with all comprehensive cardiovascular evaluation with the clinical examination, echocardiogram and electrocardiogram, and then just the baseline for our patient population. And we follow them 10 years on average until 2018, 2019. Dr. Greg Hundley: Very nice. So it sounded like from individuals in two regions of Brazil, identified those through screening of the blood, and I guess these were blood donors, and then performed a series of cardiovascular exams 2008 to 2010 and followed them for the next 10 years. And you're going to tell us about the results that occurred 2018 to 2019. And so what were those results? Dr. Maria Nunes: We found that Trypanosoma cruzi seropositive is a risk factor for developing cardiomyopathy. Nowadays, this is still a risk factor, seropositive without cardiomyopathy at baseline has two times higher risk of developing cardiomyopathy compared to the seronegative controls. And we have also detected that the parasite load or the level of parasite in the blood expressed by antibodies against Trypanosoma cruzi is an important risk factor for disease progression. That means some patients have Chagas disease, but the level of antibodies is not too high. These patients go well. And other hand, the patients with high level antibodies means the parasite load may be higher too. This is the high risk of disease progression to cardiomyopathy or of dying too. Dr. Greg Hundley: Very nice. And were there any subgroups of patients where you found these relationships to be particularly more striking? So for example, the elderly, or was there a discrepancy based on sex, men versus women? Dr. Maria Nunes: Yes, other studies has already shown that the male gender is a risk factors in Chagas disease. Usually they progress more, they have more severe clinical presentation, usually die at the age between 30 and 50 years old, the most productive years of the life. That's why Chagas is so important here in Brazil and Argentina, in Latin America countries because people die at early ages. Dr. Greg Hundley: And your results confirmed what was previously known in that regard. Dr. Maria Nunez: Yes, patients with developing cardiomyopathy with heart failure has a high mortality rate. And then even patients with cardiomyopathy detected by exams like based on ECG or echo, they asymptomatic, but they progress more for dying or to develop cardiomyopathy compared to seronegative with similar risk effects for cardiovascular disease, such as hypertension, diabetes, smoking. Dr. Greg Hundley: Very good. Well Ntobeko, you see many papers come across your desk as an Associate Editor for Circulation, and what attracted you to this paper and the results that Maria has described? Dr. Ntobeko Ntusi: Thank you, Greg. I was attracted to this paper because it's an important natural history study of Chagas disease. But secondly, it's also one of the largest contemporaneous cohorts of Chagas disease which provides important insights and advances in our knowledge with regard to this clinical entity. And for me, there were three things that stood out. The first one was an important description of the outcomes of Chagas cardiomyopathy. The second was the contemporaneous description of the epidemiology in a well-characterized cohort. And the third and novel contribution was the description of the determinants of disease progression. So I thought overall, the really important contribution to the field. Dr. Greg Hundley: Very good. And for those that might not live in the endemic area, but might occasionally encounter someone with Chagas disease, what results from this paper can we use to help manage patients in this situation? Dr. Ntobeko Ntusi: Thanks, Greg. So this was a study which had a number of really positives. Firstly, it's a large study, it was non acute [inaudible 00:16:42] design and it used PCR for diagnosis. And unlike many other studies, also ascertained antibody levels and had very good clinical characterization, which included electrocardiographic, echocardiographic assessment, including serum assessment of proBNP and CK-MB. And all really important take home messages are for me. The first one is understanding that the relationship of your antibody levels and baseline LV function to mortality. In other words, are finding that in those with existing LV structural abnormalities, or higher levels of antibody titers, mortality was higher. The second important contribution is a description of the incidence of Trypanosoma cruzi, and this was highest as one would expect in the seropositive donors and much lower in seronegative donors. The third important contribution relates to our improved understanding of the determinants of disease progression, which were related to the Trypanosoma cruzi antibody levels. In other words, the higher your antibody titers, the quicker you progressed to manifest the cardiomyopathic phenotype. And then lastly, the predictors of mortality, which were related to your PCR being positive, as well as your antibody titers. Important is this contribution is there are a number of important caveats. The first is that the study is limited by the huge amount of loss to follow up, which as you can imagine, adds a number of biases to our conclusions. The second is that the observations may of course be confounded by comorbidity in particular because these patients are older and had higher comorbidity. The third is that we assume that the PCR positivity and antibody titers actually correlate with parasite pattern, but in fact, we know that is not always the case. And then lastly, for people who read this paper from non-endemic parts of the world, the result may not be clearly generalizable to those parts of the world. Dr. Greg Hundley: Very nice. Well, we've had a great discussion, listeners. From Maria and Ntobeko sort of presenting the paper and then what are some of the take home messages. So now I'd like to go back to both of them and Maria, first you and then Ntobeko. Maria, what do you think is the next study to really be performed in this sphere of research? Dr. Maria Nunes: We may should stratify patients with Chagas disease. Those who have high antibodies titers should refer to a kind of treatment or benznidazole treatment. We should intervene in this subgroup. Dr. Greg Hundley: Very good. And Ntobeko, anything to add? Dr. Ntobeko Ntusi: Yes, Greg, I think that there are two important next steps. The first one is that I think we need other large designed prospective studies that will validate the observations by Dr. Nunes and colleagues. And then the second key step for me would be the design of randomized controlled trials to test therapeutic agents with antitrypanosomal activity to demonstrate their ability to retard or completely block disease progression, which would be a nice way to complete the story. Dr. Greg Hundley: Very nice. Well listeners, we've had a great discussion today and we want to thank Maria Nunes from Brazil and Ntobeko Ntusi from South Africa for bringing these really informative results pertaining to Chagas disease, and highlighting the natural history and showing an association between these high titer values and poor cardiovascular outcomes. Well, on behalf of Carolyn and myself, we want to wish you a great week and we will catch you next week on The Run. 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 of the American Heart Association. For more, visit ahajournals.org.
Oncotarget published "A novel E2F1-regulated lncRNA, LAPAS1, is required for S phase progression and cell proliferation" which reported that long non-coding RNAs are major regulators of many cellular processes, including cell cycle progression and cell proliferation. Inhibition of LAPAS1 expression increases the percentage of S phase cells, and its silencing in synchronized cells delays their progression through S phase. In agreement with its suggested role in cell cycle progression, prolonged inhibition of LAPAS1 attenuates proliferation of human cancer cells. Importantly, knockdown of SPNS2 rescues the effect of LAPAS1 silencing on cell cycle and cell proliferation. Summarily, they identify LAPAS1 as a novel E2F-regulated lncRNA that has a potential role in human cancer and regulates cell-cycle progression and cell proliferation, at least in part, via regulation of SPNS2. Dr. Doron Ginsberg from The Bar-Ilan University said, "The human genome expresses many thousands of long non-coding RNAs (lncRNAs), which are transcripts longer than 200 bases that lack a significant open reading frame." Increasing evidence indicates that lncRNAs are key regulators of important biological processes including cell cycle progression, cell proliferation and apoptosis. Specifically, some lncRNAs function in regulation of cell cycle progression via modulation of critical cell cycle players, such as the cyclins, CDKs, CDK inhibitors, pRB, and p53. Transcription factors that regulate mRNA transcription were shown to also regulate lncRNAs expression. Inhibition of LAPAS1 expression delays progression of cells through S phase and inhibits proliferation of human cancer cells. Thus, the authors identify LAPAS1 as a new E2F-regulated lncRNA that has a potential role in human cancer and regulates cell proliferation and cell-cycle progression, at least in part, via regulation of SPNS2. The Ginsberg Research Team concluded in their Oncotarget Research Output, "this study reports the identification of a novel lncRNA that affects cell cycle progression and cell proliferation and may affect cancer progression. Its initial characterization shows that it is transcriptionally regulated by E2F and it exerts its activity, at least in part, by regulating SPNS2." DOI - https://doi.org/10.18632/oncotarget.27962 Full text - https://www.oncotarget.com/article/27962/text/ Correspondence to - Doron Ginsberg - doron.ginsberg@biu.ac.il Keywords - lncRNA, E2F, cell cycle, cell proliferation About Oncotarget Oncotarget is a bi-weekly, peer-reviewed, open access biomedical journal covering research on all aspects of oncology. To learn more about Oncotarget, please visit https://www.oncotarget.com or connect with: SoundCloud - https://soundcloud.com/oncotarget Facebook - https://www.facebook.com/Oncotarget/ Twitter - https://twitter.com/oncotarget LinkedIn - https://www.linkedin.com/company/oncotarget Pinterest - https://www.pinterest.com/oncotarget/ Reddit - https://www.reddit.com/user/Oncotarget/ Oncotarget is published by Impact Journals, LLC please visit https://www.ImpactJournals.com or connect with @ImpactJrnls Media Contact MEDIA@IMPACTJOURNALS.COM 18009220957x105 Copyright © 2021 Impact Journals, LLC Impact Journals is a registered trademark of Impact Journals, LLC
This week's episode features author Aaron Baggish and Associate Editor & Editorialist Satyam "Tom" Sarma as they discuss the article "SARS-CoV-2 Cardiac Involvement in Young Competitive Athletes." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the Journal and its editors. We're your co-hosts ... I'm Dr. Carolyn Lam Associate Editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center from VCU health in Richmond, Virginia. Dr. Carolyn Lam: Greg, this feature discussion is just so relevant to our current times. It talks about SARS-CoV-2 cardiac involvement in young competitive athletes. Oh, one that I'm sure we're all dying to get to. Very important. But first, let's tell you what's in this week's issue. Greg, you want to go first? Dr. Greg Hundley: You bet, Carolyn. I'm going to grab a cup of coffee, and we're going to dive into the world of preclinical science. Our first paper comes to us from Professor Naftali Kaminski from Yale University. Carolyn, these investigators reprocessed human control single-cell RNA-sequencing, or scRNA sequence data from six datasets to provide a reference atlas of human lung endothelial cells to facilitate a better understanding of the phenotypic diversity and composition of cells comprising the lung endothelium. Also, the signaling network between different lung cell types was studied. Dr. Carolyn Lam: Wow. Okay. So what did they find, Greg? Dr. Greg Hundley: Six lung single-cell RNA-sequencing datasets were reanalyzed and annotated to identify over 15,000 vascular endothelial cells from 73 individuals. Beyond the broad cellular categories of lymphatic, capillary, arterial and venous endothelial cells, the co-authors found two previously indistinguishable populations. Pulmonary venous endothelial cells, called COL15A1neg localized to the lung parenchyma and systemic venous endothelial cells, COL1581positive localized to the airways and visceral pleura. Dr. Greg Hundley: Now, among capillary endothelium cells, the authors confirmed their subclassification into recently discovered aerocytes characterized by EDNRB, SOSTDC1, and TBXX2 and general capillary endothelial cells. The authors confirmed that all six endothelial cell types, including the systemic venous endothelial cells and aerocytes, are present in mice and identified endothelial marker genes conserved in both humans and mice. Dr. Greg Hundley: So Carolyn, I'm going to take a question I bet you're getting ready to ask. What are the clinical implications of this research? Well, mainly that understanding the lung endothelial diversity is crucially important to identify new therapeutic approaches for vascular diseases such as pulmonary hypertension. Dr. Carolyn Lam: Wow. That was interesting, Greg. Thank you. I've got another one from basic science world as well, and this one talks about the initial functional characterization of an exercise-induced cardiac physiological hypertrophy associated novel long non-coding RNA or LncRNA. Dr. Greg Hundley: Okay, Carolyn. Quick quiz. Can you remind us what these long-coding RNAs are? Dr. Carolyn Lam: Ha. Sure. So long non-coding RNAs or LncRNA refers to RNAs that are longer than 200 nucleotides and lack the potential to encode proteins, but have still been closely related to the occurrence and development of many diseases. Dr. Carolyn Lam: The current paper comes from co-corresponding authors, Dr. Li from the First Affiliated Hospital of Nanjing Medical University and Dr. Xiao from Shanghai University. They identified a LncRNA in the heart named cardiac physiological hypertrophy associated regulator, or CPhar. This was increased following exercise training and was necessary for exercise-induced cardiac growth. In neonatal mouse cardiomyocytes, over expression of this LncRNA induced an increase in these cardiomyocytes' size and expression of proliferation markers while inhibition of the LncRNA reduced these neonatal mouse cardiomyocytes' size and the expression of proliferative markers. Over expression of the LncRNA led to a reduction in oxygen glucose deprivation reperfusion-induced cardiomyocyte apoptosis, while LncRNA knockdown aggravated the apoptosis. Dr. Carolyn Lam: In vivo over expression of that LncRNA prevented myocardial ischemia reperfusion injury and improved cardiac function. So mechanistically though, the transcription factor, ATF7, acted as the functional downstream effector of this cardiac physiological hypertrophy associated regulator, the LncRNA. Dr. Carolyn Lam: Now Greg, following your example, I'm going to ask what are the clinical implications and tell you. So these results provide new insights into the regulation of exercise-induced cardiac physiological growth, demonstrating the cardioprotective role of this LncRNA known as cardiac physiological hypertrophy associated regulator in the heart. It also expanded our knowledge and understanding of the functions and fundamental mechanisms of LncRNAs in general. Dr. Greg Hundley: Wow, Carolyn. Beautifully described. Well, my next paper comes to us from the world of clinical science and really it's kind of something that's going to get into spending. It comes to us from Dr. Brandon Bellows from Columbia University. Dr. Greg Hundley: So Carolyn, spending on cardiovascular disease and cardiovascular risk factors, in total cardiovascular spending, accounts for a significant portion of overall US healthcare spending. The author's objective was to describe US adult cardiovascular spending patterns in 2016 and changes from 1996 to 2016, and look at the factors associated with these changes over time. Dr. Carolyn Lam: Wow. Okay. So were the authors are viewing time-dependent changes in cardiovascular spending. Is that it? What did they find? Dr. Greg Hundley: Absolutely Carolyn. So a bunch of data. Just kind of some interesting facts here. So let's work through them. Adult cardiovascular spending increased from 212 billion in 1996 to 320 billion in 2016, a period when the US population increased by over 52 million people and the median age increased from 33 to 36.9 years. Dr. Greg Hundley: Next, over this period, public insurance was responsible for the majority of cardiovascular spending at 54% followed by private insurance at 37% and out-of-pocket spending at 9%. Dr. Greg Hundley: Next, health services for ischemic heart disease at about 80 billion and hypertension, 71 billion, led to the most spending in 2016. Dr. Greg Hundley: Next, increased spending between 1996 and 2016 was primarily driven by treatment of hypertension, hyperlipidemia, and atrial fibrillation flutter on which spending rose by $42 billion, $18 billion and $16 billion respectively. Increasing service price and intensity alone were associated with 51% or 88 billion, and cardiovascular spending increased from 1996 through 2016. Whereas, changes in disease prevalence was associated with a 37% or $36 billion spending reduction over the same period after taking into account population growth and population aging. Dr. Greg Hundley: So in summary, Carolyn, US adult cardiovascular spending increased by about $100 billion from 1996 to 2016. Maybe policies tailored to control service price and intensity and preferentially reimburse higher quality care, perhaps that could help counteract future spending increases due to population aging and growth. Dr. Carolyn Lam: Oh, wow. Those are staggering numbers. Thanks Greg. Now let's go through what else is in this week's issue. There's an exchange of letters between doctors Mehmood and Houser regarding the article, Cardiac Remodeling During Pregnancy with Metabolic Syndrome: A Prologue of Pathological Remodeling. There's an ECG challenge by Dr. Real on an unusual call from the urology ward. There's also a Research Letter from Dr. Molkentin on cardiac cell therapy failing to rejuvenate the chronically scarred rodent heart. And finally a Special Report by Dr. Althouse on Recommendations for Statistical Reporting in Cardiovascular Medicine: A Special Report from the American Heart Association. Dr. Greg Hundley: Great, Carolyn, and I've got a Perspective piece entitled, Intravenous Iron Therapy in Heart Failure with Reduced Ejection Fraction: Tackling the Deficiency. It's from Professor Ardehali. Dr. Greg Hundley: Well, Carolyn, how about we get on to that feature discussion and learn more about SARS-CoV-2 in young competitive athletes. Dr. Carolyn Lam: Ooh, let's go. In our current COVID-19 pandemic a huge question is, does cardiac involvement in athletes with COVID-19 preclude their further participation in sports? What is their involvement after they've recovered from COVID-19? Guess what? Today's feature discussion is really hitting the spot with this question. So pleased to have with us the corresponding author of the feature paper, Dr. Aaron Baggish from Massachusetts General Hospital, as well as Dr. Satyam Sarma also known as Tom Sarma, our dear Associate Editor from UT Southwestern, who is also an editorialist for today's paper. So welcome Aaron and Tom. Aaron, could you start us off by describing your study and what you found? Dr. Aaron Baggish: Sure. So just very briefly, some historical context. As everyone is quite aware, when we first started seeing COVID-19 in the hospital, there was a lot of concern about what the virus did to the hearts in people that were sick enough to be hospitalized. Those of us in the sports cardiology community were quite concerned that when young athletes that developed COVID-19 infection got sick and then returned to sport, that we'd be seeing the adverse events associated with cardiac involvement. So that was the impetus to start the ORCCA Registry, which was really an opportunity to try to capture the large-scale experience with collegiate athletes returning to sport after COVID-19 infection. Indeed, with roughly 19,000 student athletes across 42 universities, there were approximately 3,000 that developed COVID-19 infection and then went through some form of cardiac screening prior to return to play. The registry was really about telling that story of what we found and what we think the implications are. Dr. Carolyn Lam: Aaron, I mean, first of all, more than 19,000 athletes recruited in just ... What was it? September 1st to December 31, 2020? How did you accomplish this amazing registry so quickly? That's amazing. Dr. Aaron Baggish: I need to acknowledge the fact that this was an incredible team effort. I was joined and continue to be joined in this by my co-PIs, Dr. Jon Drezner and Kim Harmon, who are sports medicine physicians out of the Seattle area, and the combination of cardiology, expertise and sports medicine expertise really able to pull in many of the large universities and colleges around the country, including most of the Power Five schools to participate in this registry. Dr. Aaron Baggish: In short order, team physicians from all these schools understood the importance of this work and agreed to partner with us to work very hard to enroll their student athletes and to provide us with the information we needed. Dr. Carolyn Lam: Incredible. But with the foresight, congratulations, this in and of itself is amazing. Now, could you please tell us what you found? Dr. Aaron Baggish: Sure. So we found that indeed, as we expected, that these student athletes were undergoing a fair bit of cardiac testing prior to being allowed to return to sport, and that there was variability in terms of what type of testing they were getting. The majority of schools were following what at that point were the recommendations, which were do, what we call the cardiac triad testing, which includes an echocardiogram, a high-sensitivity troponin, and an ECG and to use that information to either clear athletes or send them through further clinically indicated tests. A small number of early adopters had decided to do mandatory cardiac MRIs. So within that, we were able to understand what the prevalence, if you will, of cardiac involvement in these COVID-19 student athletes looked like, and it varied as a function of what type of tests people were doing. Dr. Carolyn Lam: And? Give us a sneak peek. Dr. Aaron Baggish: As people would expect, the more sensitive tests you do, the more abnormalities you detect. So among the schools that were using a mandatory cardiac MRI approach, there was a 3% prevalence, if you will, of either definitive, probable or possible COVID-19 cardiac involvement. When schools were following the triad testing first followed by clinically indicated CMR that prevalence was much less. It was approximately 0.5 or 0.6%. So I would emphasize that on the whole, regardless of which test was being used, that the involvement was at a much lower rate than we expected based on what we saw early in the hospitalized patient experience. So I think it's a very good news story. Dr. Carolyn Lam: Indeed. That's exactly, I think the title almost of Tom's editorial. Tom, could I bring you in here, please? Could you give us the context of this and then tell us what as editors we thought of the paper when it kind of reached out doors at Circulation? Dr. Satyam “Tom” Sarma: Sure. No, this was, I actually remember almost exactly when I was asked to handle this paper from an editorial standpoint. Joe texted me, Joe, our editor-in-chief texted me ... I think, the night, actually it was a Friday night I think ... That we had a really important paper, would you be able to take care of it on an expedited basis? I said, "Of course." So took a look at it over the weekend, and it's one of those papers when you're reading it, you almost wish you had a time machine because you realize if we had known this information eight, nine, 10, 11 months ago, it would have totally changed how we handle the pandemic from an athlete and young person standpoint. So from that aspect, I thought this is obviously a very high impact paper. Dr. Satyam “Tom” Sarma: Which then led me to the second challenge is finding the right reviewers for this paper because obviously this is a very controversial topic. We wanted to make sure we had the best reviewers we can get. The challenge, unfortunately, was that a lot of my usual go-to reviewers were actually members of the ORCCA Registry. So there were some issues with conflict of interest there, and so from a reviewer standpoint, I looked to sort of leaders in the field who had done something similar. The first thing that came to mind was really how the field has handled ECG screenings for our young athletes. I think there's, again, a perspective there that I think is very similar to how do you handle patients or young athletes with COVID and then how do you emphasize shared decision making? So from that standpoint, I had a narrow list of experts in shared decision making in sports cardiology, and really leaned on them to help guide us through the process because this is a complex paper. Dr. Satyam “Tom” Sarma: I think their feedback was instrumental in really helping to kind of distill the message, to kind of phrase things in a way that allowed the message to be easily digested by both the lay media, but more importantly, by sports trainers and athletic directors around the country. From that standpoint we really work hard and again, really thank you to Aaron and Jonathan on this manuscript because they worked so hard with our reviewers. They were incredibly responsive to almost every review comment. From that standpoint, I think the end result was amazing to really see it in final format. Dr. Carolyn Lam: I love that behind-the-scenes look. Thank you so much, Tom. What is the strong clinical implication of this? If you have questions for Aaron, please go ahead. Dr. Satyam “Tom” Sarma: Sure. No, I think the biggest thing for us as editors and sort of from the public health impact was, as Aaron mentioned, some schools have unlimited resources to really throw as much money as they can at the problem or what they think is the best approach to the problem. Again, when you have unlimited resources, you can get the "best tests." I think, unfortunately not every school in this country, both from a collegiate or high school level, has a capacity and more importantly, around the world. That's a really important limiting factor. Dr. Satyam “Tom” Sarma: Is there a way to distill the algorithm in a way that's both safe for the athletes, but more importantly is feasible for most schools? For us, that was the most important public health message was really to get that out there. The second of course, was that thinking back to last summer, just how many COVID myocarditis papers we handled in Circulation. Looking back with the again, in the heat of the battle, things are always challenging, but just to sort of see how the pendulum shifted in such a 180 degree sort of manner. So that also I think was important to get out there as well. Dr. Carolyn Lam: Yeah. And exactly why this paper is so important. So thank you once again for publishing it with Circulation. Tom though ... Okay. I mean, not to underestimate the MRI findings and so on. I think you had a question for Aaron in relation to that? Dr. Satyam “Tom” Sarma: I do. One of the challenges, again, being on the myocardial side is that we're not always experts in the papers we're assigned, and it's obviously been an incredible learning process. For me, I was hoping to pick your brain a little bit about the MRIs and sort of how you think the field will evolve from a sports cardiology standpoint. Especially as scanners get more powerful, as scanners get more sensitive, the challenges I think the field's going to have is really detecting the tiniest fleck of an abnormality. Dr. Satyam “Tom” Sarma: I think the context here is really the recent paper out of the Big 10 where they MRI'd, I believe, everyone in that registry ... I want to say it was over 2,000 athletes. Just out of curiosity, how was that handled, again, amongst your co-authors in deciding how best to present the MRI data? I like how you use the probabilistic language of it's either definite, probable or possible. How do you see that sort of progressing in terms of is that something practical that can be used by sports trainers and sports medicine staff to help restratify your athletes or athletes? Dr. Aaron Baggish: Tom, there's so much packed into that question. Let me try to unpack it piece by piece. So first off in our registry, there were a few schools that were early adopters in mandatory CMR screening, and so we wanted to very much responsibly report that. Again, there was about a 3% prevalence of something being abnormal with the myocardium based on the scans. We also realized that not all abnormalities were created equal, and that's why we did come up with that definitive, possible, probable nomenclature to really capture the fact that there were a few people that looked like they had overt myocarditis. But the vast majority had non-specific findings that those of us as clinicians pre-COVID would not have considered myocarditis. Dr. Aaron Baggish: The issue with MRI is a complicated one. The way I like to think about this as, as you mentioned earlier, is to go back to the historical experience we had with ECG screening in which doing that before we understood how to use it as a screening tool caused more problems than it solved. Dr. Aaron Baggish: It was really back in the mid-2000s when the Italians published their first ECG screening paper that the Americans got interested in it. What we learned is that if you used ECG, and this applies to MR too, without having good normative data, without understanding the cost implications, without having the experts prepared to interpret the test and deal with the downstream findings, that you're just not ready for prime time. Dr. Aaron Baggish: While I think the use of MRI as a screening technique during COVID was done with the best of intentions, I think the Big 10 paper, which is a very important dataset in this discussion, highlighted why MRI is just simply not a useful screening tool right now. If you look across their schools, they had tremendously variable rates of cardiac involvement, which is not a function of pathobiology. This virus is not different in Virginia than it is in Tennessee than it is in Wisconsin. It's just simply that people are using the tool in different ways and coming up with different findings. What we're now seeing clinically is that all these MRIs are finding a lot of stuff that either we don't want to care about or we don't want to know, and we're stuck dealing with it. So a challenge ahead of us, for sure. Dr. Satyam “Tom” Sarma: No, I think that's a really important point, Aaron. I think looking back even from a clinical standpoint in those, didn't not necessarily look at athletes, I think what you bring up is really important. The cognitive bias. Find something abnormal. I do wonder if you could talk a little bit about ... One of the other concerns we had behind the scenes was if you know an athlete, if you're an MRI reader and you know an athlete or the scan in front of you says 19-year-old athlete with COVID, can you talk a little bit about the cognitive biases that kind of go into sort of assuming either the worst case scenario, especially with athletes, because again, these are young, robust, healthy people who may or may not be on TV or in a very public format. How do you handle that as a sports cardiology in general, just kind of overcoming the cognitive bias, both from a public policy standpoint, but also from a lay public standpoint? Dr. Aaron Baggish: Yeah. So I think bias is such an interesting word to me because bias has a negative connotation, but bias actually also has some positive attributes associated with it. Bias really pushes people to be, in this situation, to be conservative and to try to do what they think is best. Dr. Aaron Baggish: But what I think it boils down to is going back to a very simple tenet and that's understanding the pre-test probability of disease. So when we interpret imaging data or exercise testing data, it always goes back to the question of why did this person get the test done in the first hand and what is our pre-test probability of finding something wrong? I think what we've learned through the COVID pandemic is that just simply having COVID does not equate with a high pre-test probability of having myocarditis in this young population. That it's really the kids that present, and these are the rare few and far between, that present with clinical findings that any doctor would think of as being consistent with myocarditis, where the scan is really helpful. The vast majority of time it's just simply not that case. Dr. Satyam “Tom” Sarma: No, I agree. I think that's always the challenge as well, too clinically as well too, with the diagnostic creep of you get one test that's kind of abnormal and the next thing you know, you're doing a cardiac biopsy and trying to figure out how you got to where you got to. Dr. Satyam “Tom” Sarma: I wanted to circle back to Carolyn's comment. I guess obviously COVID kind of really was the dominant health story over the last 12 to 14 months. Has there been a similar rash, in other words, I'm thinking back to H5N1 or some other pandemics in the past, was there a similar concern historically from the sports cardiology community with those viral outbreaks? Dr. Aaron Baggish: No. Not to my knowledge, and that's simply because there wasn't as much of an experience with hospitalized patients in the US in those prior pandemics. Again, our concern in sports cardiology world really stemmed from a very different population than the one we deal with on a daily basis. I think we learned that, although we thought that was a well-intending way to approach it, that it turned out to be an overreaction. Dr. Aaron Baggish: Before we end, I want to return to Tom's comments about the process and just share with the listeners what a satisfying process this was as an author. Having been through the peer review process, many hundreds of times with different journals, I don't remember one that was as satisfying nor one that led to as high quality of paper based on the feedback we got from the reviewers. So very much appreciative. Dr. Aaron Baggish: I also want to acknowledge the American Heart Association that has become a long-term partner in this effort. As we move out of the pandemic, the ORCCA Registry will be pivoting to really capture what happens to young athletes that are diagnosed with genetic and congenital forms of heart disease. We're very appreciative that the AHA has agreed to partner with us on this. Dr. Carolyn Lam: Aw, my goodness. Thank you so much, Aaron and Tom, for this incredible discussion. I really want to end with, if I may Tom, citing your editorial. I love the way you ended it by saying, "As Nelson Mandela said, 'Sports has the power to change the world. It has the power to inspire. It has the power to unite people in a way that little else does.'" We got seriously scared with COVID-19, but this paper is just so important in providing some reassurance that there has not been a single case of cardiac complication to date, documented to be clearly related to COVID-19 in this population. It's a real testament to the hard work that you've put in. So thank you. Thank you very much for this paper. For all the effort. Thank you both for being here to discuss this. Dr. Carolyn Lam: Well, audience, you've been listening to Circulation on the Run. Thanks for joining us today, and don't forget to join us again next week. Dr. Greg Hundley: 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 of the American Heart Association. For more, visit ahajournals.org.
I am James Rozelle, a senior double majoring in Biochemistry and Molecular and Cellular Biology. I also love math so I decided to do a math minor while at the UofA. I work in the Beilstein lab which is interested in phylogenetics and genomic. Specifically I’ve been working on projects that investigate something called long non coding RNAs or lncRNAs for short. I’ve had a long time fascination with biological sciences, how things work biochemically, and especially how that understanding can help us better interact with the world around us to lead healthier and more aware lives. This summer I will be applying to medical schools but until then I’ll be working as the director of the UofA chapter of a non profit called Camp Kesem which organizes free summer camps for children impacted by their parent’s cancer. This and last summer camps had to be virtual but were still a blast. I also love to hike and play piano when time allows.
This episode, we're tackling the science behind autoimmune disorders like Celiac and Crohn's disease with Columbia PhD student Alyssa Shearer! Alyssa shares more about her research studying the genetics behind these diseases, the science policies she hopes to see for patients, and how she got involved in science advocacy. For our science PhD friends feeling burned out by the lab, Alyssa is here to inspire!If you want to learn more about the topics discussed in this episode, check out: March for Science NYC websiteLack of diversity in genetic research a problem (news article)Doctors once thought bananas cured Celiac Disease. They saved kids' lives - at a cost. (news article)Genetics of Celiac Disease and Gluten Sensitivity (blog post)What are lncRNAs and lincRNAs? (website)Don't forget to follow us on Twitter @SpotlightThePod to stay up-to-date on all news and episode releases!Learn more about Northwestern University SPOT on Twitter @SPOTForceNU or at our website spot.northwestern.eduPodcast artwork created by Edie Jiang, available at her website https://ediejiang.weebly.com/ or on Instagram @ediejiangMusic in this episode: Earth by MusicbyAden https://soundcloud.com/musicbyadenCreative Commons — Attribution-ShareAlike 3.0 Unported — CC BY-SA 3.0Free Download / Stream: https://bit.ly/_earthMusic promoted by Audio Library https://youtu.be/5yIbZVOv438
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.11.16.384826v1?rss=1 Authors: Ari Yuka, S., Yilmaz, A. Abstract: Competing endogenous RNA (ceRNA) regulations and crosstalk between various types of non-coding RNA in human is an important and under-explored subject. Several studies have pointed out that an alteration in miRNA:target interaction can result in unexpected changes due to indirect and complex interactions. In this paper, we defined a new network-based model that incorporates miRNA:ceRNA interactions with expression values and then calculates network-wide effects after perturbation in expression level of element(s) while utilizing miRNA interaction factors such as seed type, binding energy. We have carried out analysis of large scale miRNA:target networks from breast cancer patients. Highly perturbing genes identified by our approach coincide with breast cancer associated genes and miRNAs. Our network-based approach helps unveiling the crosstalk between node elements in miRNA:target network where abundance of targets leading to sponge effect is taken into account. The model has potential to reveal unforeseen and unpredicted regulations which are only evident when considered in network context. Our tool is scalable and can be plugged in with emerging miRNA effectors such as circRNAs, lncRNAs and available as R package ceRNAnetsim https://www.bioconductor.org/packages/release/bioc/html/ceRNAnetsim.html . Copy rights belong to original authors. Visit the link for more info
In his Part 2, Chang introduces long noncoding RNAs, or lncRNAs. As their name suggests, lncRNAs are not translated into proteins, and initially their functions were poorly understood. Chang's group has developed technologies to better understand the function of lncRNAs. For example, his lab characterized the protein partners that interact with Xist, a canonical lncRNA that mediates X chromosome inactivation. They found that the protein Spen is necessary for X chromosome silencing. Interestingly, Spen has likely been co-opted by mammalian cells to inactivate the X chromosome via viral mimicry.
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.14.296921v1?rss=1 Authors: Olgun, G., Tastan, O. Abstract: The dysregulation of long non-coding RNAs' (lncRNAs) expressions has been implicated in cancer. Since most of the lncRNAs' are not functionally characterized well, investigating the set of perturbed lncRNAs are is challenging. Existing methods that inspect lncRNAs functionally rely on the co-expressed coding genes, which are far better characterized functionally. LncRNAs can be known to act as transcriptional regulators; they may activate or repress the neighborhood's coding genes on the genome. Based on this, in this work, we aim to analyze the deregulated lncRNAs in cancer by taking into account their ability to regulate nearby loci on the genome. We perform functional analysis on differentially expressed lncRNAs for 28 different cancers considering their adjacent coding genes. We identify that some deregulated lncRNAs are cancer-specific, but a substantial number of lncRNAs are shared across cancers. Next, we assess the similarities of the cancer types based on the functional enrichment of the deregulated lncRNA sets. We find some cancers are very similar in the functions and biological processes related to the deregulated lncRNAs. We observe that some of the cancers for which we find similarity can be linked through primary, metastatic site relations. We investigate the similarity of enriched functional terms for the deregulated lncRNAs and the mRNAs. We further assess the enriched functions' similarity to the functions and processes that the known cancer driver genes take place. We believe that our methodology help to understand the impact of the lncRNAs in cancer functionally. Copy rights belong to original authors. Visit the link for more info
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.10.291526v1?rss=1 Authors: Puthanveettil, S., Grinman, E., Nakahata, Y., Avchalumov, Y., Swarnkar, S., Yasuda, R. Abstract: Activity dependent structural plasticity at the synapse requires specific changes in the neuronal transcriptome. While much is known about the role of coding elements in this process, the role of the long-noncoding transcriptome remains elusive. Here we report the discovery of an intronic long noncoding RNA (lncRNA),termed ADEPTR, whose expression is upregulated and is synaptically transported in a cAMP/PKA dependent manner in hippocampal neurons, independent of its protein-coding host gene. Loss of ADEPTR function suppresses activity-dependent changes in synaptic transmission and structural plasticity of dendritic spines. Mechanistically, dendritic localization of ADEPTR is mediated by molecular motor protein Kif2A. ADEPTR physically binds to actin-scaffolding regulators Ankyrin (AnkB) and Spectrin (Sptn1) and is required for their dendritic localization. Taken together, this study demonstrates that ADEPTR regulates the dendritic Spectrin-Ankyrin network for structural plasticity at the synapse and illuminates a novel role for lncRNAs at the synapse. Copy rights belong to original authors. Visit the link for more info
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.10.236562v1?rss=1 Authors: Roule, T., Ariel, F., Hartmann, C., Crespi, M., Blein, T. Abstract: Clustered organization of biosynthetic non-homologous genes is emerging as a characteristic feature of plant genomes. The co-regulation of clustered genes seems to largely depend on epigenetic reprogramming and three-dimensional chromatin conformation. Here we identified the long noncoding RNA (lncRNA) MARneral Silencing (MARS), localized inside the Arabidopsis marneral cluster, and which controls the local epigenetic activation of its surrounding region in response to ABA. MARS modulates the POLYCOMB REPRESSIVE COMPLEX 1 (PRC1) component LIKE-HETEROCHROMATIN PROTEIN 1 (LHP1) binding throughout the cluster in a dose-dependent manner, determining H3K27me3 deposition and chromatin condensation. In response to ABA, MARS decoys LHP1 away from the cluster and promotes the formation of a chromatin loop bringing together the MARNERAL SYNTHASE 1 (MRN1) locus and a distal ABA-responsive enhancer. The enrichment of co-regulated lncRNAs in clustered metabolic genes in Arabidopsis suggests that the acquisition of novel noncoding transcriptional units may constitute an additional regulatory layer driving the evolution of biosynthetic pathways. Copy rights belong to original authors. Visit the link for more info
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.27.223446v1?rss=1 Authors: Leitner, D. F., Mills, J. D., Pires, G., Faustin, A., Drummond, E., Kanshin, E., Nayak, S., Askenazi, M., Verducci, C., Chen, B. J., Janitz, M., Anink, J. J., Baayen, J. C., Idema, S., van Vliet, E. A., Devore, S., Friedman, D., Diehl, B. V., Scott, C., Thijs, R., Wisniewski, T., Ueberheide, B., Thom, M., Aronica, E., Devinsky, O. Abstract: Sudden unexpected death in epilepsy (SUDEP) is the leading type of epilepsy-related death. Severely depressed brain activity in these cases may impair respiration, arousal, and protective reflexes, occurring as a prolonged postictal generalized EEG suppression (PGES) and resulting in a high-risk for SUDEP. In autopsy hippocampus and cortex, we observed no proteomic differences between SUDEP and epilepsy cases, contrasting our previously reported robust differences between epilepsy and controls. Transcriptomics in hippocampus and cortex from surgical epilepsy cases segregated by PGES identified 55 differentially expressed genes (37 protein-coding, 15 lncRNAs, three pending) in hippocampus. Overall, the SUDEP proteome and high-risk SUDEP transcriptome largely reflected other epilepsy cases in the brain regions analyzed, consistent with diverse epilepsy syndromes and comorbidities associated with SUDEP. Thus, studies with larger cohorts and different epilepsy syndromes, as well as additional anatomic regions may identify molecular mechanisms of SUDEP. Copy rights belong to original authors. Visit the link for more info
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.27.221218v1?rss=1 Authors: Delorme, J., Wang, L., Kodoth, V., Wang, Y., Ma, J., Aton, S. Abstract: The hippocampus plays an essential role in consolidating transient experiences into long-lasting memories. Memory consolidation can be facilitated by post-learning sleep, although the underlying cellular mechanisms are undefined. Here, we addressed this question using a mouse model of hippocampally-mediated, sleep-dependent memory consolidation (contextual fear memory; CFM), which is known to be disrupted by post-learning sleep loss. We used translating ribosome affinity purification (TRAP) to quantify ribosome-associated RNAs in different subcellular compartments (cytosol and membrane) and in different hippocampal cell populations (either whole hippocampus, Camk2a+ excitatory neurons, or highly active neurons expressing phosphorylated ribosomal subunit S6 [pS6+]). Using RNA-seq, we examined how these transcript profiles change as a function of sleep vs. sleep deprivation (SD) and as a function of prior learning (contextual fear conditioning; CFC). Surprisingly, we found that while many mRNAs on cytosolic ribosomes were altered by sleep loss, almost none were altered by learning. Of the few changes in cytosolic ribosomal transcript abundance following CFC, almost all were occluded by subsequent SD. This effect was particularly pronounced in pS6+ neurons with the highest level of neuronal activity following CFC, suggesting SD-induced disruption of post-learning transcript changes in putative engram neurons. In striking contrast, far fewer transcripts on membrane-bound (MB) ribosomes were altered by SD, and many more mRNAs (and lncRNAs) were altered on MB ribosomes as a function of prior learning. For hippocampal neurons, cellular pathways most significantly affected by CFC were involved in structural remodeling. Comparisons of post-CFC transcript profiles between freely-sleeping and SD mice implicated changes in cellular metabolism in Camk2a+ neurons, and increased protein synthesis capacity in pS6+ neurons, as biological processes disrupted by post-learning sleep loss. Copy rights belong to original authors. Visit the link for more info
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.22.215855v1?rss=1 Authors: Luo, H., Bu, D., Shao, L., Li, Y., Sun, L., Wang, C., Wang, J., Yang, W., Yang, X., Dong, J., Zhao, Y., Li, F. Abstract: The development of new therapeutic targets for cancer immunotherapies and the development of new biomarkers require deep understanding of T cells. To date, the complete landscape and systematic characterization of long noncoding RNAs (lncRNAs) in T cells in cancer immunity are lacking. Here, by systematically analyzing full-length single-cell RNA sequencing (scRNA-seq) data of more than 20,000 T cell libraries across three cancer types, we provide the first comprehensive catalog and the functional repertoires of lncRNAs in human T cells. Specifically, we developed a custom pipeline for de novo transcriptome assembly obtaining 9,433 novel lncRNA genes that increased the number of current human lncRNA catalog by 16% and nearly doubled the number of lncRNAs expressed in T cells. We found that a portion of expressed genes in single T cells were lncRNAs which have been overlooked by the majority of previous studies. Based on metacell maps constructed by MetaCell algorithm that partition scRNA-seq datasets into disjointed and homogenous groups of cells (metacells), 154 signature lncRNAs associated with effector, exhausted, and regulatory T cell states are identified, 84 of which are functionally annotated based on co-expression network, indicating that lncRNAs might broadly participate in regulation of T cell functions. Our findings provide a new point of view and resource for investigating the mechanisms of T cell regulation in cancer immunity as well as for novel cancer-immune biomarker development and cancer immunotherapies. Copy rights belong to original authors. Visit the link for more info
Lee elaborates on the early steps of X inactivation. Very early in development, cells “count” the number of X chromosomes and decide if one needs to be inactivated, and if so which one. There is a region of the X chromosome called the X inactivation center which is enriched in long non-coding RNAs (lncRNAs). Lee explains how she and others showed that by sensing the ratio of two specific lncRNAs the cell can determine how many X chromosomes are present. Further studies showed that two different lncRNAs are responsible for randomly determining which X chromosome will be inactivated. Finally, she discusses the hypothesis that the allelic choice mechanism depends on a transient chromosomal pairing event that occurs at the beginning of the dosage compensation process.
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.17.046441v1?rss=1 Authors: Chen, Z., Zhang, D., Reynolds, R. H., Gustavsson, E. K., Garcia Ruiz, S., D'Sa, K., Fairbrother-Browne, A., Vandrovcova, J., Genomics Consortium (IPDGC), I. P. D., Hardy, J., Houlden, H., Gagliano Taliun, S. A., Botia, J. A., Ryten, M. Abstract: Knowledge of genomic features specific to the human lineage may provide insights into brain-related diseases. We leverage high-depth whole genome sequencing data to generate a combined annotation identifying regions simultaneously depleted for genetic variation (constrained regions) and poorly conserved across primates. We propose that these constrained, non-conserved regions (CNCRs) have been subject to human-specific purifying selection and are enriched for brain-specific elements. We find that CNCRs are depleted from protein-coding genes but enriched within lncRNAs. We demonstrate that per-SNP heritability of a range of brain-relevant phenotypes are enriched within CNCRs. We find that genes implicated in neurological diseases have high CNCR density, including APOE, highlighting an unannotated intron-3 retention event. Using human brain RNA-sequencing data, we show the intron-3-retaining transcript/s to be more abundant in Alzheimer's disease with more severe tau and amyloid pathological burden. Thus, we demonstrate the importance of human-lineage-specific sequences in brain development and neurological disease. We release our annotation through vizER (https://snca.atica.um.es/browser/app/vizER). Copy rights belong to original authors. Visit the link for more info