54 results found
Jones RE, Gruszczyk AV, Schmidt C, et al., 2023, Assessment of left ventricular tissue mitochondrial bioenergetics in patients with stable coronary artery disease, Nature Cardiovascular Research, Vol: 2, Pages: 733-745, ISSN: 2731-0590
Recurrent myocardial ischemia can lead to left ventricular (LV) dysfunction in patients with coronary artery disease (CAD). In this observational cohort study, we assessed for chronic metabolomic and transcriptomic adaptations within LV myocardium of patients undergoing coronary artery bypass grafting. During surgery, paired transmural LV biopsies were acquired on the beating heart from regions with and without evidence of inducible ischemia on preoperative stress perfusion cardiovascular magnetic resonance. From 33 patients, 63 biopsies were acquired, compared to analysis of LV samples from 11 donor hearts. The global myocardial adenosine triphosphate (ATP):adenosine diphosphate (ADP) ratio was reduced in patients with CAD as compared to donor LV tissue, with increased expression of oxidative phosphorylation (OXPHOS) genes encoding the electron transport chain complexes across multiple cell types. Paired analyses of biopsies obtained from LV segments with or without inducible ischemia revealed no significant difference in the ATP:ADP ratio, broader metabolic profile or expression of ventricular cardiomyocyte genes implicated in OXPHOS. Differential metabolite analysis suggested dysregulation of several intermediates in patients with reduced LV ejection fraction, including succinate. Overall, our results suggest that viable myocardium in patients with stable CAD has global alterations in bioenergetic and transcriptional profile without large regional differences between areas with or without inducible ischemia.
Kanemaru K, Cranley J, Muraro D, et al., 2023, Spatially resolved multiomics of human cardiac niches, Nature, Vol: 619, Pages: 801-810, ISSN: 0028-0836
The function of a cell is defined by its intrinsic characteristics and its niche: the tissue microenvironment in which it dwells. Here we combine single-cell and spatial transcriptomics data to discover cellular niches within eight regions of the human heart. We map cells to microanatomical locations and integrate knowledge-based and unsupervised structural annotations. We also profile the cells of the human cardiac conduction system1. The results revealed their distinctive repertoire of ion channels, G-protein-coupled receptors (GPCRs) and regulatory networks, and implicated FOXP2 in the pacemaker phenotype. We show that the sinoatrial node is compartmentalized, with a core of pacemaker cells, fibroblasts and glial cells supporting glutamatergic signalling. Using a custom CellPhoneDB.org module, we identify trans-synaptic pacemaker cell interactions with glia. We introduce a druggable target prediction tool, drug2cell, which leverages single-cell profiles and drug-target interactions to provide mechanistic insights into the chronotropic effects of drugs, including GLP-1 analogues. In the epicardium, we show enrichment of both IgG+ and IgA+ plasma cells forming immune niches that may contribute to infection defence. Overall, we provide new clarity to cardiac electro-anatomy and immunology, and our suite of computational approaches can be applied to other tissues and organs.
Miranda AMA, Janbandhu V, Maatz H, et al., 2023, Single-cell transcriptomics for the assessment of cardiac disease, NATURE REVIEWS CARDIOLOGY, Vol: 20, Pages: 289-308, ISSN: 1759-5002
Tadros R, Zheng SL, Grace C, et al., 2023, Large scale genome-wide association analyses identify novel genetic loci and mechanisms in hypertrophic cardiomyopathy., medRxiv
Hypertrophic cardiomyopathy (HCM) is an important cause of morbidity and mortality with both monogenic and polygenic components. We here report results from the largest HCM genome-wide association study (GWAS) and multi-trait analysis (MTAG) including 5,900 HCM cases, 68,359 controls, and 36,083 UK Biobank (UKB) participants with cardiac magnetic resonance (CMR) imaging. We identified a total of 70 loci (50 novel) associated with HCM, and 62 loci (32 novel) associated with relevant left ventricular (LV) structural or functional traits. Amongst the common variant HCM loci, we identify a novel HCM disease gene, SVIL, which encodes the actin-binding protein supervillin, showing that rare truncating SVIL variants cause HCM. Mendelian randomization analyses support a causal role of increased LV contractility in both obstructive and non-obstructive forms of HCM, suggesting common disease mechanisms and anticipating shared response to therapy. Taken together, the findings significantly increase our understanding of the genetic basis and molecular mechanisms of HCM, with potential implications for disease management.
Reichart D, Lindberg EL, Maatz H, et al., 2022, Pathogenic variants damage cell compositions and single cell transcription in cardiomyopathies, Publisher: OXFORD UNIV PRESS, Pages: 2992-2992, ISSN: 0195-668X
Lota A, Hazebroek M, Theotokis P, et al., 2022, Genetic architecture of acute myocarditis and the overlap with inherited cardiomyopathy, Circulation, Vol: 146, Pages: 1123-1134, ISSN: 0009-7322
Background: Acute myocarditis is an inflammatory condition that may herald the onset of dilated (DCM) or arrhythmogenic cardiomyopathy (ACM). We investigated the frequency and clinical consequences of DCM and ACM genetic variants in a population-based cohort of patients with acute myocarditis. Methods: Population-based cohort of 336 consecutive patients with acute myocarditis enrolled in London and Maastricht. All participants underwent targeted DNA-sequencing for well-characterised cardiomyopathy-associated genes with comparison to healthy controls (n=1053) sequenced on the same platform. Case ascertainment in England was assessed against national hospital admission data. The primary outcome was all-cause mortality. Results: Variants that would be considered pathogenic if found in a patient with DCM or ACM were identified in 8% of myocarditis cases compared to <1% of healthy controls (p=0.0097). In the London cohort (n=230; median age 33years; 84% men), patients were representative of national myocarditis admissions (median age 32years; 71% men; 66% case ascertainment), and there was enrichment of rare truncating variants (tv) in ACM-associated genes (3.1% cases vs 0.4% controls; odds ratio 8.2; p=0.001). This was driven predominantly by desmoplakin (DSP)-tv in patients with normal LV ejection fraction and ventricular arrhythmia. In Maastricht (n=106; median age 54years; 61% men), there was enrichment of rare truncating variants in DCM-associated genes, particularly TTN-tv found in 7% (all with LVEF<50%) compared to 1% in controls (OR 3.6; p=0.0116). Across both cohorts over a median of 5.0 years (IQR 3.9-7.8), all-cause mortality was 5.4%. Two thirds of deaths were cardiovascular, due to worsening heart failure (92%) or sudden cardiac death (8%). The 5-year mortality risk was 3.3% in genotype negative patients versus 11.1% for genotype positive patients (Padjusted=0.08). Conclusions: We identified DCM- or ACM-associated genetic variants in 8% of patients wit
Reichart D, Lindberg EL, Maatz H, et al., 2022, Pathogenic variants damage cell composition and single-cell transcription in cardiomyopathies, Science, Vol: 377, Pages: 1-13, ISSN: 0036-8075
INTRODUCTIONHuman heart failure is a highly morbid condition that affects 23 million individuals worldwide. It emerges in the setting of an array of different cardiovascular disorders, which has propelled the notion that diverse stimuli converge on a common final pathway. Consistent with this, initiating etiologies do not direct heart failure treatments, which are often inadequate and necessitate mechanical interventions and cardiac transplantation.The recent application of single-nucleus RNA sequencing (snRNAseq) transcriptional analyses to characterize the cellular composition and molecular states in the healthy adult human heart provides an emerging benchmark by which disease-related changes can be assessed. Moreover, the discovery of human pathogenic variants that cause dilated cardiomyopathy (DCM) and arrhythmogenic cardiomyopathy (ACM), disorders associated with high rates of heart failure, provides direct opportunities to evaluate whether genotype influences heart failure pathways.RATIONALEA systematic identification of shared and distinct molecules and pathways involved in heart failure is lacking, and knowledge of these fundamental data could propel the development of more effective treatments. To enable these discoveries, we performed snRNAseq of explanted ventricular tissues from 18 healthy donors and 61 heart failure patients. By focusing analyses on multiple samples with pathogenic variants in DCM genes (LMNA, RBM20, and TTN), ACM genes (PKP2), or pathogenic variant–negative (PV negative) samples, we characterized genotype-stratified and common heart failure responses.RESULTSFrom 881,081 nuclei isolated from left and right diseased and healthy ventricles, we identified 10 major cell types and 71 distinct transcriptional states. DCM and ACM tissues showed significant depletion of cardiomyocytes and increased endothelial and immune cells. Fibrosis was expanded in disease hearts, but, unexpectedly, fibroblasts were not increased, and instead showed a
Raja AA, Wakimoto H, DeLaughter DM, et al., 2022, Ablation of lysophosphatidic acid receptor 1 attenuates hypertrophic cardiomyopathy in a mouse model, Proceedings of the National Academy of Sciences of USA, Vol: 119, Pages: 1-12, ISSN: 0027-8424
Myocardial fibrosis is a key pathologic feature of hypertrophic cardiomyopathy (HCM). However, the fibrotic pathways activated by HCM-causing sarcomere protein gene mutations are poorly defined. Because lysophosphatidic acid is a mediator of fibrosis in multiple organs and diseases, we tested the role of the lysophosphatidic acid pathway in HCM. Lysphosphatidic acid receptor 1 (LPAR1), a cell surface receptor, is required for lysophosphatidic acid mediation of fibrosis. We bred HCM mice carrying a pathogenic myosin heavy-chain variant (403+/−) with Lpar1-ablated mice to create mice carrying both genetic changes (403+/− LPAR1 −/−) and assessed development of cardiac hypertrophy and fibrosis. Compared with 403+/− LPAR1WT, 403+/− LPAR1 −/− mice developed significantly less hypertrophy and fibrosis. Single-nucleus RNA sequencing of left ventricular tissue demonstrated that Lpar1 was predominantly expressed by lymphatic endothelial cells (LECs) and cardiac fibroblasts. Lpar1 ablation reduced the population of LECs, confirmed by immunofluorescence staining of the LEC markers Lyve1 and Ccl21a and, by in situ hybridization, for Reln and Ccl21a. Lpar1 ablation also altered the distribution of fibroblast cell states. FB1 and FB2 fibroblasts decreased while FB0 and FB3 fibroblasts increased. Our findings indicate that Lpar1 is expressed predominantly by LECs and fibroblasts in the heart and is required for development of hypertrophy and fibrosis in an HCM mouse model. LPAR1 antagonism, including agents in clinical trials for other fibrotic diseases, may be beneficial for HCM.
Lota AS, Hazebroek M, Theotokis P, et al., 2021, Genetic Overlap of Acute Myocarditis and Inherited Cardiomyopathy, Annual Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Brito L, Mylonaki I, Grigsby CL, et al., 2021, Genetic Enhancement of Epicardial Paracrine Signalling for Cardiac Regeneration, Annual Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
McCracken IR, Saginc G, He L, et al., 2021, Lack of evidence of ACE2 expression and replicative infection by SARSCoV-2 in human endothelial cells, Circulation, Vol: 143, Pages: 865-868, ISSN: 0009-7322
Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require deeper understanding of the healthy heart’s molecular processes. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavor. Here, using state-of-the-art analyses of large-scale single-cell and nuclei transcriptomes, we characterise six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes, and fibroblasts, revealing distinct atrial and ventricular subsets with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment we identify cardiac resident macrophages with inflammatory and protective transcriptional signatures. Further, inference of cell-cell interactions highlight different macrophage-fibroblast-cardiomyocyte networks between atria and ventricles that are distinct from skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a healthy reference for future studies.
Constantinou C, Miranda Almeida A, Chaves Guerrero P, et al., 2020, Human pluripotent stem cell-derived cardiomyocytes as a targetplatform for paracrine protection by cardiac mesenchymal stromalcells, Scientific Reports, Vol: 10, ISSN: 2045-2322
Ischemic heart disease remains the foremost cause of death globally, with survivors at risk for subsequent heart failure. Paradoxically, cell therapies to offset cardiomyocyte loss after ischemic injury improve long-term cardiac function despite a lack of durable engraftment. An evolving consensus, inferred preponderantly from non-human models, is that transplanted cells benefit the heart via early paracrinesignals. Here, we tested the impact of paracrine signals on human cardiomyocytes, using human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) as the target of mouse and human cardiac mesenchymal stromal cells (cMSC) with progenitor-like features. In co-culture and conditioned medium studies, cMSCs markedly inhibited human cardiomyocyte death. Little or no protection was conferred by mouse tail tip or human skin fibroblasts. Consistent with the results of transcriptomic profiling, functional analyses showed that the cMSC secretome suppressed apoptosis and and preserved cardiac mitochondrial transmembrane potential. Protection was independent of exosomes under the conditions tested. In mice, injecting cMSC-conditioned media into the infarct border zone reduced apoptotic cardiomyocytes >70% locally. Thus, hPSC-CMs provide an auspicious, relevant human platform to investigate extracellular signals for cardiac muscle survival, substantiating human cardioprotection by cMSCs, and suggesting the cMSC secretome or its components as potential cell-free therapeutic products.
Sungnak W, Huang N, Bécavin C, et al., 2020, SARS-CoV-2 entry factors are highly expressed in nasal epithelial cells together with innate immune genes., Nat Med, Vol: 26, Pages: 681-687
We investigated SARS-CoV-2 potential tropism by surveying expression of viral entry-associated genes in single-cell RNA-sequencing data from multiple tissues from healthy human donors. We co-detected these transcripts in specific respiratory, corneal and intestinal epithelial cells, potentially explaining the high efficiency of SARS-CoV-2 transmission. These genes are co-expressed in nasal epithelial cells with genes involved in innate immunity, highlighting the cells' potential role in initial viral infection, spread and clearance. The study offers a useful resource for further lines of inquiry with valuable clinical samples from COVID-19 patients and we provide our data in a comprehensive, open and user-friendly fashion at www.covid19cellatlas.org.
Fiedler LR, Chapman K, Xie M, et al., 2020, MAP4K4 Inhibition Promotes Survival of Human Stem Cell-Derived Cardiomyocytes and Reduces Infarct Size <i>In Vivo</i> (vol 24, 579.e1,2019), CELL STEM CELL, Vol: 26, Pages: 458-458, ISSN: 1934-5909
Constantinou C, Noseda M, Chaves P, et al., 2019, Human Cardiomyocyte Protection From Apoptosis by Cardiac Progenitor Cell Secreted Factors, Scientific Sessions of the American-Heart-Association, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Schneider M, Fiedler L, Chapman K, et al., 2019, MAP4K4 inhibition promotes survival of human stem cell derived cardiomyocyte and reduces infarct size in vivo, Cell Stem Cell, Vol: 24, Pages: 579-591.e12, ISSN: 1875-9777
Heart disease is a paramount cause of global death and disability. Although cardiomyocyte death plays a causal role and its suppression would be logical, no clinical counter-measures target the responsible intracellular pathways. Therapeutic progress has been hampered by lack of preclinical human validation. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is activated in failing human hearts and relevant rodent models. Using human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) and MAP4K4 gene silencing, we demonstrate that death induced by oxidative stress requires MAP4K4. Consequently, we devised a small-molecule inhibitor, DMX-5804, that rescues cell survival, mitochondrial function, and calcium cycling in hiPSC-CMs. As proof of principle that drug discovery in hiPSC-CMs may predict efficacy in vivo, DMX-5804 reduces ischemia-reperfusion injury in mice by more than 50%. We implicate MAP4K4 as a well-posed target toward suppressing human cardiac cell death and highlight the utility of hiPSC-CMs in drug discovery to enhance cardiomyocyte survival.
Noseda M, Samari S, Chaves P, et al., 2019, Modulation of Macrophage Differentiation and Activation: Paracrine Signals from Cardiac Progenitor Cells, Publisher: SPRINGER, Pages: 262-262, ISSN: 0920-3206
Massaia A, Chaves P, Samari S, et al., 2018, Single cell gene expression to understand the dynamic architecture of the heart, Frontiers in Cardiovascular Medicine, Vol: 5, ISSN: 2297-055X
The recent development of single cell gene expression technologies, and especially singlecell transcriptomics, have revolutionized the way biologists and clinicians investigateorgans and organisms, allowing an unprecedented level of resolution to the descriptionof cell demographics in both healthy and diseased states. Single cell transcriptomicsprovide information on prevalence, heterogeneity, and gene co-expression at theindividual cell level. This enables a cell-centric outlook to define intracellular generegulatory networks and to bridge toward the definition of intercellular pathwaysotherwise masked in bulk analysis. The technologies have developed at a fast paceproducing a multitude of different approaches, with several alternatives to choose fromat any step, including single cell isolation and capturing, lysis, RNA reverse transcriptionand cDNA amplification, library preparation, sequencing, and computational analyses.Here, we provide guidelines for the experimental design of single cell RNA sequencingexperiments, exploring the current options for the crucial steps. Furthermore, we providea complete overview of the typical data analysis workflow, from handling the rawsequencing data to making biological inferences. Significantly, advancements in singlecell transcriptomics have already contributed to outstanding exploratory and functionalstudies of cardiac development and disease models, as summarized in this review. Inconclusion, we discuss achievable outcomes of single cell transcriptomics’ applicationsin addressing unanswered questions and influencing future cardiac clinical applications.
Shanmuganathan M, Vughs J, Noseda M, et al., 2018, Exosomes: Basic biology and technological advancements suggesting their potential as ischemic heart disease therapeutics, Frontiers in Physiology, Vol: 9, ISSN: 1664-042X
Exosomes are small nano-sized vesicles that deliver biologically active RNA molecules and proteins to recipient cells through binding, fusion or endocytosis. There is emerging evidence that endogenous exosomes released by cardiovascular cells and progenitor cells impact cell survival and proliferation, thus regulating angiogenesis, cardiac protection and repair. These cardioprotective and regenerative traits have the potential to translate in to novel therapeutic options for post-ischaemic cardiac regeneration, thus potentially delaying the progression to ischaemic heart failure. Cellular stressors influence exosomes' secretion and the molecular composition of the exosome cargo, thus impacting on the above processes. Evidences are emerging that loading of proteins and RNAs in the exosomes cargos can be manipulated. Similarly, manipulation of exosomes surface proteins' expression to target exosomes to specific cells and tissues is doable. In addition, nature-inspired synthetic exosomes can be assembled to deliver specific clues to the recipient cells, including proliferative and differentiation stimuli, or shed paracrine signals enabling to reconstructing the heart homeostatic micro-environment. This review will describe exosome biogenesis and emerging evidence of exosome-mediated regenerative cell-to-cell communications and will conclude discussing possibilities of using exosomes to treat ischemic heart disease.
Noseda M, Harding SE, 2018, Understanding dynamic tissue organization by studying the human body one cell at a time: the human cell atlas (HCA) project, CARDIOVASCULAR RESEARCH, Vol: 114, Pages: E93-E95, ISSN: 0008-6363
Adamowicz M, Morgan CC, Haubner BJ, et al., 2018, Functionally conserved noncoding regulators of cardiomyocyte proliferation and regeneration in mouse and human, Circulation: Cardiovascular Genetics, Vol: 11, ISSN: 1942-325X
Background: The adult mammalian heart has little regenerative capacity after myocardial infarction (MI), whereas neonatal mouse heart regenerates without scarring or dysfunction. However, the underlying pathways are poorly defined. We sought to derive insights into the pathways regulating neonatal development of the mouse heart and cardiac regeneration post-MI.Methods and Results: Total RNA-seq of mouse heart through the first 10 days of postnatal life (referred to as P3, P5, P10) revealed a previously unobserved transition in microRNA (miRNA) expression between P3 and P5 associated specifically with altered expression of protein-coding genes on the focal adhesion pathway and cessation of cardiomyocyte cell division. We found profound changes in the coding and noncoding transcriptome after neonatal MI, with evidence of essentially complete healing by P10. Over two-thirds of each of the messenger RNAs, long noncoding RNAs, and miRNAs that were differentially expressed in the post-MI heart were differentially expressed during normal postnatal development, suggesting a common regulatory pathway for normal cardiac development and post-MI cardiac regeneration. We selected exemplars of miRNAs implicated in our data set as regulators of cardiomyocyte proliferation. Several of these showed evidence of a functional influence on mouse cardiomyocyte cell division. In addition, a subset of these miRNAs, miR-144-3p, miR-195a-5p, miR-451a, and miR-6240 showed evidence of functional conservation in human cardiomyocytes.Conclusions: The sets of messenger RNAs, miRNAs, and long noncoding RNAs that we report here merit further investigation as gatekeepers of cell division in the postnatal heart and as targets for extension of the period of cardiac regeneration beyond the neonatal period.
Noseda M, Constantinou C, Samari S, et al., 2017, Abstract 191: Paracrine Impact of Cardiac Progenitor Cells on Macrophage Phenotypes and Human Ipsc-derived Cardiomyocyte Survival, Basic Cardiovascular Sciences Scientific Sessions of the American-Heart-Association - Pathways to Cardiovascular Therapeutics, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7330
Speidel AT, Stuckey DJ, Chow LW, et al., 2017, Multi-modal hydrogel-based platform to deliver and monitor cardiac progenitor/stem cell engraftment, ACS Central Science, Vol: 3, Pages: 338-348, ISSN: 2374-7951
Retention and survival of transplanted cells are major limitations to the efficacy of regenerative medicine, with short-term paracrine signals being the principal mechanism underlying current cell therapies for heart repair. Consequently, even improvements in short-term durability may have a potential impact on cardiac cell grafting. We have developed a multimodal hydrogel-based platform comprised of a poly(ethylene glycol) network cross-linked with bioactive peptides functionalized with Gd(III) in order to monitor the localization and retention of the hydrogel in vivo by magnetic resonance imaging. In this study, we have tailored the material for cardiac applications through the inclusion of a heparin-binding peptide (HBP) sequence in the cross-linker design and formulated the gel to display mechanical properties resembling those of cardiac tissue. Luciferase-expressing cardiac stem cells (CSC-Luc2) encapsulated within these gels maintained their metabolic activity for up to 14 days in vitro. Encapsulation in the HBP hydrogels improved CSC-Luc2 retention in the mouse myocardium and hind limbs at 3 days by 6.5- and 12- fold, respectively. Thus, this novel heparin-binding based, Gd(III)-tagged hydrogel and CSC-Luc2 platform system demonstrates a tailored, in vivo detectable theranostic cell delivery system that can be implemented to monitor and assess the transplanted material and cell retention.
Wei K, Serpooshan V, Hurtado C, et al., 2015, Epicardial FSTL1 reconstitution regenerates the adult mammalian heart, Nature, Vol: 525, Pages: 479-485, ISSN: 0028-0836
The elucidation of factors that activate the regeneration of the adult mammalian heart is of major scientific and therapeutic importance. Here we found that epicardial cells contain a potent cardiogenic activity identified as follistatin-like 1 (Fstl1). Epicardial Fstl1 declines following myocardial infarction and is replaced by myocardial expression. Myocardial Fstl1 does not promote regeneration, either basally or upon transgenic overexpression. Application of the human Fstl1 protein (FSTL1) via an epicardial patch stimulates cell cycle entry and division of pre-existing cardiomyocytes, improving cardiac function and survival in mouse and swine models of myocardial infarction. The data suggest that the loss of epicardial FSTL1 is a maladaptive response to injury, and that its restoration would be an effective way to reverse myocardial death and remodelling following myocardial infarction in humans.
Morez CY, Noseda M, Abreu Paiva M, et al., 2015, Enhanced efficiency of genetic programming toward cardiomyocyte creation through topographical cues, Biomaterials, Vol: 70, Pages: 94-104, ISSN: 1878-5905
Generation of de novo cardiomyocytes through viral over-expression of key transcription factors represents a highly promising strategy for cardiac muscle tissue regeneration. Although the feasibility of cell reprogramming has proven possible both in vitro and in vivo, the efficiency of the process remains extremely low. Here, we report a chemical-free technique in which topographical cues, more specifically parallel microgrooves, enhance the trans-differentiation of cardiac progenitors into cardiomyocyte-like cells. Using a lentivirus-mediated direct reprogramming strategy for expression of Myocardin, Tbx5, and Mef2c, we showed that the microgrooved substrate provokes an increase in histone H3 acetylation (AcH3), known to be a permissive environment for reprogramming by “stemness” factors, as well as stimulation of myocardin sumoylation, a post-translational modification essential to the transcriptional function of this key co-activator. These biochemical effects mimicked those of a pharmacological histone deacetylase inhibitor, valproic acid (VPA), and like VPA markedly augmented the expression of cardiomyocyte-specific proteins by the genetically engineered cells. No instructive effect was seen in cells unresponsive to VPA. In addition, the anisotropy resulting from parallel microgrooves induced cellular alignment, mimicking the native ventricular myocardium and augmenting sarcomere organization.
Harada M, Noseda M, Schneider M, 2015, The Cre / Lox P fate mapping study on cardiac progenitor cells revealed its embryonic origin with its intrinsic methodological limitation validated by single cell qRT-PCR, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 950-950, ISSN: 0195-668X
Noseda M, Abreu-Paiva M, Schneider MD, 2015, The Quest for the Adult Cardiac Stem Cell, Circulation Journal, Vol: 79, Pages: 1422-1430, ISSN: 1347-4820
Over the past 2 decades, cardiac regeneration has evolved from an exotic fringe of cardiovascular biology to theforefront of molecular, genetic, epigenetic, translational, and clinical investigations. The unmet patient need is thepaucity of self-repair following infarction. Robust regeneration seen in models such as zebrafish and newborn micehas inspired the field, along with encouragement from modern methods that make even low levels of restorativegrowth discernible, changing the scientific and technical landscape for effective counter-measures. Approachesunder study to augment cardiac repair complement each other, and encompass grafting cells of diverse kinds,restarting the cell cycle in post-mitotic ventricular myocytes, reprogramming non-myocytes, and exploiting the dormantprogenitor/stem cells that lurk within the adult heart. The latter are the emphasis of the present review. Cardiacresidentstem cells (CSC) can be harvested from heart tissue, expanded, and delivered to the myocardium as atherapeutic product, whose benefits may be hoped to surpass those achieved in human trials of bone marrow.However, important questions are prompted by such cells’ discovery. How do they benefit recipient hearts? Do theycontribute, measurably, as an endogenous population, to self-repair? Even if “no,” might CSCs be targets for activationin situ by growth factors and other developmental catalysts? And, what combination of distinguishing markersbest demarcates the cells with robust clonal growth and cardiogenic potential?
Belian E, Noseda M, Abreu Paiva MS, et al., 2015, Forward Programming of Cardiac Stem Cells by Homogeneous Transduction with MYOCD plus TBX5., PLOS One, Vol: 10, ISSN: 1932-6203
UNLABELLED: Adult cardiac stem cells (CSCs) express many endogenous cardiogenic transcription factors including members of the Gata, Hand, Mef2, and T-box family. Unlike its DNA-binding targets, Myocardin (Myocd)-a co-activator not only for serum response factor, but also for Gata4 and Tbx5-is not expressed in CSCs. We hypothesised that its absence was a limiting factor for reprogramming. Here, we sought to investigate the susceptibility of adult mouse Sca1+ side population CSCs to reprogramming by supplementing the triad of GATA4, MEF2C, and TBX5 (GMT), and more specifically by testing the effect of the missing co-activator, Myocd. Exogenous factors were expressed via doxycycline-inducible lentiviral vectors in various combinations. High throughput quantitative RT-PCR was used to test expression of 29 cardiac lineage markers two weeks post-induction. GMT induced more than half the analysed cardiac transcripts. However, no protein was detected for the induced sarcomeric genes Actc1, Myh6, and Myl2. Adding MYOCD to GMT affected only slightly the breadth and level of gene induction, but, importantly, triggered expression of all three proteins examined (α-cardiac actin, atrial natriuretic peptide, sarcomeric myosin heavy chains). MYOCD + TBX was the most effective pairwise combination in this system. In clonal derivatives homogenously expressing MYOCD + TBX at high levels, 93% of cardiac transcripts were up-regulated and all five proteins tested were visualized. IN SUMMARY: (1) GMT induced cardiac genes in CSCs, but not cardiac proteins under the conditions used. (2) Complementing GMT with MYOCD induced cardiac protein expression, indicating a more complete cardiac differentiation program. (3) Homogeneous transduction with MYOCD + TBX5 facilitated the identification of differentiating cells and the validation of this combinatorial reprogramming strategy. Together, these results highlight the pivotal importance of MYOCD in driving CSCs toward a cardiac muscle fate
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