Studying the effect of sarcomeric MYH7R663H and non-sarcomeric BRAFT599R hypertrophic cardimyopathy mutations in human induced pluripotent stemm cell-derived cardiomyocytes
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE332763 | GEO | 2026/06/26
REPOSITORIES: GEO
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Project description:Myosin inhibitor mavacamten is the first targeted treatment available for hypertrophic cardiomyopathy (HCM), a disease caused by hundreds of genetic variants that affect mainly sarcomeric myosin and its negative regulator cardiac myosin-binding protein C (cMyBP-C, encoded by MYBPC3). Here, we have examined whether the reported limited efficacy of mavacamten in a fraction of HCM patients can result from dissimilar HCM pathomechanisms triggered by different genetic variants, a scenario particularly relevant for MYBPC3-associated HCM. To this aim, we have generated knock-in mice including missense pathogenic variant cMyBP-C p.R502W, which, different from patients who carry truncations in the protein, develop progressive pathogenic myocardial remodeling in the absence of alterations of cMyBP-C levels and localization. Mechanistically, mutation R502W reduces the binding affinity of cMyBP-C for myosin, increases Ca2+ sensitivity and promotes the ON structural state of myosin heads without inducing a shift towards more active myosin conformations as observed when cMyBP-C levels are reduced. Despite these differences, we demonstrate that mavacamten blunts myocardial remodeling both in R502W and cMyBP-C-deficient, knock-out hearts, correlating with its ability to normalize the levels of ON myosins in R502W sarcomeres. These beneficial effects are accompanied by improved tolerance to exercise in R502W animals. In human engineered heart tissues carrying R502W, we show that mavacamten opposes hypercontractility induced by the mutation. Hence, in combination our results indicate that myosin inhibition is effective to treat HCM caused by both truncating and missense variants in MYBPC3 regardless of the primary pathomechanisms they elicit.
2026-06-02 | GSE326721 | GEO
Project description:Myosin inhibitor mavacamten is the first targeted treatment available for hypertrophic cardiomyopathy (HCM), a disease caused by hundreds of genetic variants that affect mainly sarcomeric myosin and its negative regulator cardiac myosin-binding protein C (cMyBP-C, encoded by MYBPC3). Here, we have examined whether the reported limited efficacy of mavacamten in a fraction of HCM patients can result from dissimilar HCM pathomechanisms triggered by different genetic variants, a scenario particularly relevant for MYBPC3-associated HCM. To this aim, we have generated knock-in mice including missense pathogenic variant cMyBP-C p.R502W, which, different from patients who carry truncations in the protein, develop progressive pathogenic myocardial remodeling in the absence of alterations of cMyBP-C levels and localization. Mechanistically, mutation R502W reduces the binding affinity of cMyBP-C for myosin, increases Ca2+ sensitivity and promotes the ON structural state of myosin heads without inducing a shift towards more active myosin conformations as observed when cMyBP-C levels are reduced. Despite these differences, we demonstrate that mavacamten blunts myocardial remodeling both in R502W and cMyBP-C-deficient, knock-out hearts, correlating with its ability to normalize the levels of ON myosins in R502W sarcomeres. These beneficial effects are accompanied by improved tolerance to exercise in R502W animals. In human engineered heart tissues carrying R502W, we show that mavacamten opposes hypercontractility induced by the mutation. Hence, in combination our results indicate that myosin inhibition is effective to treat HCM caused by both truncating and missense variants in MYBPC3 regardless of the primary pathomechanisms they elicit.
2026-06-02 | GSE326720 | GEO
Project description:Myosin inhibitor mavacamten is the first targeted treatment available for hypertrophic cardiomyopathy (HCM), a disease caused by hundreds of genetic variants that affect mainly sarcomeric myosin and its negative regulator cardiac myosin-binding protein C (cMyBP-C, encoded by MYBPC3). Here, we have examined whether the reported limited efficacy of mavacamten in a fraction of HCM patients can result from dissimilar HCM pathomechanisms triggered by different genetic variants, a scenario particularly relevant for MYBPC3-associated HCM. To this aim, we have generated knock-in mice including missense pathogenic variant cMyBP-C p.R502W, which, different from patients who carry truncations in the protein, develop progressive pathogenic myocardial remodeling in the absence of alterations of cMyBP-C levels and localization. Mechanistically, mutation R502W reduces the binding affinity of cMyBP-C for myosin, increases Ca2+ sensitivity and promotes the ON structural state of myosin heads without inducing a shift towards more active myosin conformations as observed when cMyBP-C levels are reduced. Despite these differences, we demonstrate that mavacamten blunts myocardial remodeling both in R502W and cMyBP-C-deficient, knock-out hearts, correlating with its ability to normalize the levels of ON myosins in R502W sarcomeres. These beneficial effects are accompanied by improved tolerance to exercise in R502W animals. In human engineered heart tissues carrying R502W, we show that mavacamten opposes hypercontractility induced by the mutation. Hence, in combination our results indicate that myosin inhibition is effective to treat HCM caused by both truncating and missense variants in MYBPC3 regardless of the primary pathomechanisms they elicit.
2026-06-02 | PXD076207 | Pride
Project description:Hypertrophic cardiomyopathy (HCM) is a complex disease partly explained by the effects of individual gene variants on sarcomeric protein biomechanics. At the cellular level, HCM mutations most commonly enhance force production, leading to higher energy demands. Despite significant advances in elucidating sarcomeric structure-function relationships, there is still much to be learned about the mechanisms that link altered cardiac energetics to HCM phenotypes. In this work, we test the hypothesis that changes in cardiac energetics represent a common pathophysiologic pathway in HCM. We performed a comprehensive multi-omics profile of the molecular (transcripts, metabolites, and complex lipids), ultrastructural, and functional components of HCM energetics using myocardial samples from 27 HCM patients and 13 normal controls (donor hearts). Integrated omics analysis revealed alterations in a wide array of biochemical pathways with major dysregulation in fatty acid metabolism, reduction of acylcarnitines, and accumulation of free fatty acids. HCM hearts showed evidence of global energetic decompensation manifested by a decrease in high energy phosphate metabolites (ATP, ADP, and phosphocreatine) and a reduction in mitochondrial genes involved in the creatine kinase and ATP synthesis. Accompanying these metabolic derangements, quantitative electron microscopy showed an increased fraction of severely damaged mitochondria with reduced cristae density, coinciding with reduced citrate synthase (CS) activity and mitochondrial oxidative respiration. These mitochondrial abnormalities were associated with elevated reactive oxygen species (ROS) and reduced antioxidant defenses. However, despite significant mitochondrial injury, HCM hearts failed to upregulate mitophagic clearance. Overall, our findings suggest that perturbed metabolic signaling and mitochondrial dysfunction are common pathogenic mechanisms in patients with HCM. These results highlight potential new drug targets for attenuation of the clinical disease through improving metabolic function and reducing mitochondrial injury.
2022-07-17 | GSE180313 | GEO
Project description:Our research has demonstrated the following: (1) Confirmed that MYH7 mutations D239N, H251N, G256E lead to hypercontractility in hiPSC-derived cardiomyocytes (hiPSC-CMs); (2) Increase in YAP’s nuclear localization in both hiPSC-CMs and patient tissue with MYH7 HCM mutations; (3) A correlation between YAP's nuclear localization and enhanced force generation; (4) Nuclear deformation as a mechanism enabling YAP's nuclear entry and activation; (5) Transcriptomic changes resulting from positive and negative modifications in force generation; and (6) A distinctive paracrine hypertrophic signal reliant on cardiomyocyte-cardiac fibroblast crosstalk. Our unique insights to the intricacies of hypertrophic cardiomyopathy phenotypes hold the potential to provide mechanistic clarity, informing potential therapeutic strategies.
2025-01-01 | GSE261296 | GEO
Project description:Hypertrophic cardiomyopathy (HCM) is an important cause leading to heart failure. Preserving cardiac function particularly in cardiomyocytes (CMs) is essential for improving prognosis in HCM patients. Therefore, understanding single-cell transcriptome characteristics of CMs in HCM would be indispensable to investigate potential therapeutic targets. We applied single-cell tagged reverse transcription (STRT-seq) approach and obtained 338 CM transcriptomes. The human heart samples were collected from HCM patients who had extended septal myectomy and healthy donors. Our results revealed that in nonfailing HCM heart CMs could be categorized into three subsets: high energy synthesis cluster, high cellular metabolism cluster and intermediate cluster. The expression of mitochondrial and electron transport chain (ETC) was up-regulated in larger-sized CMs from high energy synthesis cluster. Of note, we found the expression of Cytochrome c oxidase subunit 7B (Cox7B), a subunit of Complex IV in ETC was positively correlated with CMs size. Further, after assessing Cox7B expression in HCM patients, we speculated that Cox7B was compensatory up-regulated at early-stage but down-regulated at end-stage of HCM. To test the hypothesis that Cox7B might play a cardioprotective role in the early-stage of HCM, we used adeno associated virus 9 (AAV9) to mediate the expression of Cox7B in pressure overload-induced mice. Mice in vivo data supported that knockdown of Cox7B would accelerate heart failure progression and Cox7B overexpression could restore partial cardiac function in hypertrophy.
2024-02-07 | GSE227734 | GEO
Project description:Aims: Hypertrophic cardiomyopathy (HCM) caused by autosomal-dominant mutations in genes coding for structural sarcomeric proteins, is the most common inherited heart disease. HCM is associated with progressive myocardial hypertrophy, fibrosis, ventricular dysfunction, and arrhythmias. Hypoxia together with hypoxia-inducible transcription factor-1a (HIF1A) is the central master regulators of cellular hypoxia response and associated with HCM. Yet their exact role remains to be elucidated. Therefore, the effect of a cardiomyocyte-specific Hif-1a knockout (cHif1aKO) was studied in an established α-MHC719/+ HCM mouse model that exhibits the classical features of human HCM. Results: HIF-1α protein and HIF downstream targets were upregulated in left ventricular tissue of α-MHC719/+ mice. Cardiomyocyte-specific abolishment of Hif-1a did not cause cardiac abnormalities in wild type (WT) mice and resulted in amelioration of disease phenotype in α-MHC719/+ mice, as evidenced by decreased left ventricular wall thickness, reduced myocardial fibrosis, reduced disordered SRX/DRX state and diminished ROS production. In addition, cHif1aKO induced normalization of pro-hypertrophic and pro-fibrotic left ventricular remodeling signaling evidenced on whole transcriptome and proteomics analysis in α-MHC719/+ mice. Proteomics of serum samples from patients with early onset HCM compared to age-and gender-matched healthy controls revealed significant upregulation of HIF targets IGF2, LTBP1, RECK and downregulation of WDR1. Innovation and Conclusion: Overall, these results demonstrate for the first time that HIF signaling is involved in mouse and human HCM pathogenesis. Cardiomyocyte-specific knockout of Hif-1a attenuates disease phenotype in the HCM α-MHC719/+ mouse model. Targeting HIF-1α might serve as a therapeutic option to mitigate HCM disease progression.
2025-01-22 | GSE266649 | GEO
Project description:Hypertrophic cardiomyopathy (HCM) constitutes the most common genetic cardiac disorder. However, current pharmacotherapeutics are mainly symptomatic and only partially address underlying molecular mechanisms. Circular RNAs (circRNAs) are a recently discovered class of non-coding RNAs and emerged as specific and powerful regulators of cellular functions. By performing global circRNA-specific next generation sequencing in cardiac tissue of patients with hypertrophic cardiomyopathy compared to healthy donors, we identified circZFPM2 (hsa_circ_0003380. CircZFPM2, which derives from the ZFPM2 locus, is a highly conserved regulatory circRNA that is strongly induced in HCM tissue. In vitro loss-of-function experiments were performed in neonatal rat cardiomyocytes, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), and HCM-patient-derived hiPSC-CMs. A knockdown of circZFPM2 was found to induce cardiomyocyte hypertrophy and compromise mitochondrial respiration, leading to an increased production of reactive oxygen species and apoptosis. In contrast, delivery of recombinant circZFPM2, packaged in lipid-nanoparticles or using AAV-based overexpression, rescued cardiomyocyte hypertrophic gene expression and promoted cell survival. Additionally, HCM-derived cardiac organoids exhibited improved contractility upon CM-specific overexpression of circZFPM2. Multi-Omics analysis further promoted our hypothesis, showing beneficial effects of circZFPM2 on cardiac contractility and mitochondrial function. Collectively, our data highlight that circZFPM2 serves as a promising target for the treatment of cardiac hypertrophy including HCM.
2024-04-25 | GSE261129 | GEO
Project description:Introduction: Variants in PRKAG2 cause hypertrophic cardiomyopathy (HCM) and conduction disturbances. While prior studies associated PRKAG2-related hypertrophy with increased glycogen storage, many HCM phenotypes remain unexplained. We aimed to uncover how PRKAG2 variants induce myocyte hypertrophy and electrical changes during early cardiac development. Methods: We generated transgenic zebrafish expressing wild-type (TgWT) or pathogenic variant (TgR299Q) Prkag2 cDNA under a myocardium-specific promoter, and examined cardiac electrophysiology, contractile function, and cytoarchitecture during cardiogenesis and in adult hearts. Results: TgR299Q fish showed hypertrophic cardiomyocytes and progressive contractile abnormalities, recapitulating human HCM phenotypes. Cardiomyocyte glycogen was elevated in adult but not embryonic hearts. Despite the absence of glycogen accumulation at 6-day post-fertilization, TgR299Q hearts showed electrical abnormalities, including reduced conduction velocity and prolonged action potential and Ca2+ transient durations. We observed decreased AMPK phosphorylation in the TgR299Q hearts. However, AMPK activation did not rescue the electrophysiological abnormalities in TgR299Q. Proximity ligation assays and co-immunoprecipitation identified a physical interaction between AMPKγ2 and myosin, enhanced by the R299Q variant and accompanied by increased AMPKγ2 localization to the myofilament. Na+/Ca2+ exchanger (NCX) inhibition increased Ca2+ duration and diastolic Ca2+ in TgWT but not TgR299Q hearts, indicating reduced free cytosolic Ca2+ for NCX-mediated extrusion in TgR299Q. These findings suggest that enhanced AMPKγ2-myosin interaction may promote myofilament Ca2+ retention, thereby prolonging Ca2+ transient duration and APD in the mutant. Notably, the myosin inhibitor mavacamten reduced AMPKγ2-myosin interaction in TgR299Q hearts, and both mavacamten and vmhcl knockdown rescued the early electrophysiological abnormalities. Conclusions: The PRKAG2 variant altered cardiac excitability, contractility, and Ca2+ handling during cardiogenesis, independent of glycogen accumulation. Enhanced interactions between AMPKγ2 and myosin contributed to these early changes. Our study revealed a novel link between cellular energy sensing and contractile machinery, with therapeutic potential for modulating contractile function in cardiomyopathies.
2026-05-26 | GSE333349 | GEO
Project description:This a model from the article:
Mitochondrial energetic metabolism: a simplified model of TCA cycle with ATP production.
Nazaret C, Heiske M, Thurley K, Mazat JP J. Theor. Biol.
2009 Jun;258(3):455-64 19007794
,
Abstract:
Mitochondria play a central role in cellular energetic metabolism. The essential parts of this metabolism are the tricarboxylic acid (TCA) cycle, the respiratory chain and the adenosine triphosphate (ATP) synthesis machinery. Here a simplified model of these three metabolic components with a limited set of differential equations is presented. The existence of a steady state is demonstrated and results of numerical simulations are presented. The relevance of a simple model to represent actual in vivo behavior is discussed.
2024-09-02 | BIOMD0000000232 | BioModels