Search Results (2,366)

Background/Objectives: Dilated cardiomyopathy (DCM) is a prevalent and life-threatening heart muscle disease often caused by titin (TTN) truncating variants (TTNtv). While TTNtvs are the most common genetic cause of heritable DCM, the precise downstream regulatory mechanisms linking TTN deficiency to cardiac dysfunction and maladaptive fibrotic remodeling remain incompletely understood. This study aimed to identify key epigenetic regulators of TTN-mediated gene expression and explore their potential as therapeutic targets, utilizing human patient data and in vitro models. Methods: We analyzed RNA sequencing (RNA-seq) data from left ventricles of non-failing donors and cardiomyopathy patients (DCM, HCM, PPCM) (GSE141910). To model TTN deficiency, we silenced TTN in human iPSC-derived cardiomyocytes (iPSC-CMs) and evaluated changes in cardiac function genes (MYH6, NPPA) and fibrosis-associated genes (COL1A1, COL3A1, COL14A1). We further tested the effects of TMP-195, a class IIa histone deacetylase (HDAC) inhibitor, and individual knockdowns of HDAC4/5/7/9. Results: In both human patient data and the TTN knockdown iPSC-CM model, TTN deficiency suppressed MYH6 and NPPA while upregulating fibrosis-associated genes. Treatment with TMP-195 restored NPPA and MYH6 expression and suppressed collagen genes, without altering TTN expression. Among the HDACs tested, HDAC5 knockdown was most consistently associated with improved cardiac markers and reduced fibrotic gene expression. Co-silencing TTN and HDAC5 replicated these beneficial effects. Furthermore, the administration of TMP-195 enhanced the modulation of NPPA and COL1A1, though its impact on COL3A1 and COL14A1 was not similarly enhanced. Conclusions: Our findings identify HDAC5 as a key epigenetic regulator of maladaptive gene expression in TTN deficiency. Although the precise mechanisms remain to be clarified, the ability of pharmacological HDAC5 inhibition with TMP-195 to reverse TTN-deficiency-induced gene dysregulation highlights its promising translational potential for TTN-related cardiomyopathies. Full article

Heart failure (HF) and other cardiac pathologies represent leading causes of hospitalization and mortality worldwide, underscoring the urgent need for effective regenerative therapies. In recent years, considerable research has focused on developing cell-based therapeutic strategies, with stem cells receiving particular attention. Approaches that harness cellular signaling pathways have also been investigated. Experimental studies conducted in both animal models and human subjects have demonstrated that cell-based therapies hold remarkable potential, showing efficacy through improvements in cardiac function, patient quality of life, and overall safety. Clinical data concerning therapies based on cellular signals, while sometimes inconclusive, often yield outcomes comparable to or even superior to those of cell-based interventions. Nonetheless, both approaches face substantial challenges, including the need to ensure reproducibility of results, standardization of therapeutic product preparation, and addressing ethical and regulatory considerations. To translate these promising strategies into clinical practice, a greater number of large-scale, multicenter, and diverse clinical trials will be required. Full article

Arrhythmogenic cardiomyopathy (ACM) is a genetic cardiac disease characterized by a progressive loss of cardiomyocytes associated with fibrofatty myocardial replacement, resulting in a heightened risk of ventricular arrhythmias and sudden cardiac death. ACM is a common cause of sudden death in young individuals, and exercise has been proven to be a factor in disease progression. Current therapeutic strategies, including lifestyle modification, antiarrhythmic pharmacological therapy, catheter ablation, and the placement of implantable cardioverter-defibrillators, remain primarily palliative options rather than addressing the underlying molecular substrate. The pathogenesis of ACM includes complex molecular and cellular mechanisms, linking genetic mutations to structural and electrical anomalies of the ventricle. The lack of targeted therapies contributes to a challenging approach to the disease. It highlights the need for a better understanding of the mechanisms that lead to myocardial remodeling and arrhythmic predisposition. With the help of animal models (especially murine) and induced pluripotent stem cells, there have been advances in understanding the molecular pathogenesis of ACM. In this review, we summarized some of the pathogenic molecular pathways involved in the development of ACM and emerging therapies targeted towards disease modification, not just prevention. Full article

Bromodomain and extraterminal domain (BET) proteins act as epigenetic regulators of gene transcription. BET inhibitors have shown therapeutic potential in various models of heart failure; however, their efficacy in atrial fibrillation (AF) remains incompletely understood. This study investigated the effects of the BET inhibitor JQ1 in a mice model of AF. Wild-type male C57BL/6 mice were randomized into four groups: control, JQ1 alone (50 mg/kg, intraperitoneal), angiotensin II (AngII; 1 μg/kg/min), and AngII plus JQ1. After 2 weeks, electrophysiological studies revealed that JQ1 significantly reduced AngII-induced AF inducibility and duration. It also attenuated left atrial enlargement, diastolic dysfunction, and cardiac fibrosis. Molecular analyses indicated that JQ1 suppressed the AngII-induced upregulation of pro-fibrotic genes and restored Sirt1 expression. Moreover, JQ1 also inhibited AngII-enhanced oxidized CaMKII and phosphorylated RyR2 levels. In HL-1 atrial cardiomyocytes, JQ1 improved calcium handling abnormalities, shortened prolonged action potential duration (APD), and restored mitochondrial respiration and adenosine triphosphate (ATP) production, all of which had been impaired by AngII. These findings suggest that BET inhibition by JQ1 mitigates structural and electrical remodeling associated with AF by attenuating atrial fibrosis, and by restoring calcium homeostasis, mitochondrial function, and Sirt1 expression. JQ1 may represent a novel therapeutic strategy for the prevention and treatment of AF. Full article

Aging is a major risk factor for cardiovascular disease, driving progressive structural and functional decline of the myocardium. Mitochondria, the primary source of ATP through oxidative phosphorylation, are essential for cardiac contractility, calcium homeostasis, and redox balance. In the aging heart, mitochondria show morphological alterations including cristae disorganization, swelling, and fragmentation, along with reduced OXPHOS efficiency. These defects increase proton leak, lower ATP production, and elevate reactive oxygen species (ROS), causing oxidative damage. Concurrent disruptions in mitochondrial fusion and fission further impair turnover and quality control, exacerbating mitochondrial dysfunction and cardiac decline. Serum response factor (SRF) signaling, a crucial regulator of cytoskeletal and metabolic gene expression, plays a key role in modulating mitochondrial function during cardiac aging. Dysregulation of SRF impairs mitochondrial adaptability, contributing to dysfunction. Additionally, reduced levels of nicotinamide adenine dinucleotide (NAD⁺) hinder sirtuin-dependent deacetylation, further compromising mitochondrial efficiency and stress resilience. These cumulative defects activate regulated cell death pathways, leading to cardiomyocyte loss, fibrosis, and impaired diastolic function. Mitochondrial dysfunction therefore serves as both a driver and amplifier of cardiac aging, accelerating the transition toward heart failure. This narrative review aims to provide a comprehensive overview of mitochondrial remodeling in the aging myocardium, examining the mechanistic links between mitochondrial dysfunction and myocardial injury. We also discuss emerging therapeutic strategies targeting mitochondrial bioenergetics and quality control as promising approaches to preserve cardiac function and extend cardiovascular health span in the aging population. Full article

Doxorubicin (Dox) is a widely used anti-cancer drug. It has proven efficacy against various cancers, although the clinical application of Dox has been limited due to dose-dependent, irreversible, and fatal Dox-induced cardiotoxicity (DIC). The mechanism of DIC remains unclear. p53 plays a key role in DIC via cardiomyocyte loss due to cell death and oxidative stress. Its expression is strictly controlled by post-translational modifications, and its suppression in cardiomyocytes reportedly ameliorates DIC. The ubiquitin system regulates biological processes that are fundamental to the development of cardiovascular diseases. The dysregulation of several ubiquitin E3 ligases is reportedly associated with DIC development through the upregulation of p53. Ubiquitin E3 ligases are classified into four groups; all classes of E3 ligases are involved in p53 degradation. In this review, we focus on recently emerging topics regarding the role of E3 ligases in the regulation of p53 degradation. We also provide an overview of the functional roles of E3 ligases in DIC. Recent reports have identified cardioprotective agents for DIC through ubiquitin E3 ligase-mediated p53 suppression. Here, we present some findings regarding the current development of cardioprotective agents for DIC. These agents may serve as a novel therapeutic target for the treatment of DIC. Full article

Hypertrophic cardiomyopathy (HCM) is a relatively common global cardiac disease, usually inherited, with complex phenotypes, genetic features, and a natural history. In this study, we constructed atic^−/− zebrafish using the CRISPR/Cas9 gene-editing system and found that atic^−/− zebrafish hearts exhibited HCM symptoms, and atic^−/− zebrafish hearts showed progressive enlargement, eccentric hypertrophy, cardiomyocyte enlargement, and collagen fiber deposition. Echocardiography results also showed that compared with atic^−/− zebrafish hearts, in wild-type zebrafish hearts, the ejection fraction was significantly reduced, shortening fraction was reduced, and ventricular wall thickness was significantly increased. Meanwhile, aerobic exercise intervention in atic^−/− zebrafish showed that aerobic exercise effectively improved the symptoms of HCM and improved cardiac function in atic^−/− zebrafish hearts. Transcriptome sequencing results showed that aerobic exercise improved the symptoms of HCM in atic^−/− zebrafish hearts involving the calcium signaling pathway, Apelin signaling pathway and ECM–receptor interaction. The q-PCR results of key differential genes involved in these pathways further confirmed that aerobic exercise could bring beneficial effects to atic^−/− zebrafish. In conclusion, this study found that the loss of ATIC can lead to hypertrophic cardiomyopathy in zebrafish, and aerobic exercise intervention can effectively improve the hypertrophic pathological characteristics of atic^−/− zebrafish hearts, providing new intervention targets and effective lifestyle interventions for HCM. Full article

Myocardial infarction (MI) remains a leading cause of mortality worldwide, yet effective cardioprotective strategies remain limited in clinical settings. Vascular endothelial growth factor B (VEGFB) has emerged as a promising therapeutic candidate in MI, but the role of its co-receptor, Neuropilin-1 (NRP1), in cardiomyocyte (CM) survival under ischemic stress remains poorly understood. Here, we investigated VEGFB-NRP1 signaling using an in vivo zebrafish model of cardiac injury as well as in vitro hypoxia models in CMs. We demonstrated that VEGFB overexpression conferred protection against ischemic injury and enhanced cardiac regeneration in the zebrafish heart. Mechanistically, we showed that VEGFB treatment enhances CM viability through reducing reactive oxygen species (ROS), ferroptosis activation, and preserving mitochondrial integrity. We also demonstrated that NRP1 knockdown in the CMs abolished the VEGFB-mediated protective effects, indicating the significant role of NRP1 signaling in VEGFB-induced cardioprotective effects in MI. Lastly, using transcriptome analysis, we confirmed that VEGFB induces anti-apoptotic and anti-ferroptosis gene programs in CMs in response to hypoxic stress. Collectively, our findings provide mechanistic insight into cell death activation pathways, including ferroptosis, in response to ischemic stress and further validate the therapeutic potential of VEGFB in promoting CM survival in ischemic heart disease. Full article

Resveratrol may protect against radiation by modulating cellular metabolism and enhancing the cellular response to stress. Here, we explored its effects on human cardiomyocytes exposed to ionizing radiation. Resveratrol (5 µM) was administered for 1, 7, and 30 days before a single 2 Gy dose of irradiation, and then radiation toxicity and changes in the proteome were evaluated. Extended resveratrol treatment (7 or 30 days) induced more profound proteomic changes than one-day treatment and partially counteracted toxic effects of radiation, leading to increased cell survival, reduced cell death, and fewer cells arrested in the G1 phase. Though resveratrol administration itself had a greater impact on the proteome than radiation alone, we identified three subsets of proteins differently affected by radiation depending on the resveratrol context. The first subset (84 differentially expressed proteins; DEPs) represented proteins influenced by radiation in all resveratrol pretreatment regimens. The second subset (228 DEPs), linked to DNA repair, cell cycle checkpoints, and apoptosis, was affected by radiation only in the absence of resveratrol preconditioning, indicating the compound’s protective effect. The third subset (252 DEPs) involved in metabolism regulation appeared only after extended resveratrol preconditioning. In conclusion, the results demonstrate that hypothetical time-dependent cardioprotective effects of resveratrol are linked to significant proteomic reprogramming of cardiomyocytes caused by long-term pretreatment. Full article

Connexin 26 (Cx26), a gap junction protein, is poorly understood in the context of cardiac milieu, including extracellular vesicles (EVs). Here, we report for the first time the presence of Cx26 on EVs obtained from human induced pluripotent stem cell-derived cardiomyocytes and human plasma. Using an in vitro model of oxidative stress and apoptosis in dH9c2 cardiomyocytes, we observed a significant decrease in Cx26 levels in EVs released by injured cells, accompanied by changes in EV concentration, particularly in exosomes. Our findings revealed that Cx26 modulates the selective loading of specific microRNAs, namely miR-1 and miR-30a, into EVs, suggesting a novel non-canonical, gap junction-independent role of Cx26 in EV-mediated cardiac signaling. Analysis of plasma EVs from healthy donors confirmed the presence of Cx26-positive EVs of cardiomyocyte origin, indicated by co-staining with cardiac troponin T. These findings suggest that further studies on the measurement of Cx26 on circulating EVs from patients with ischemic heart disease and heart failure are warranted to clarify its potential as a biomarker for cardiomyocyte injury in cardiomyopathies with oxidative stress and apoptosis. Full article

Adult cardiomyocytes (CMs) lose their proliferative capacity shortly after birth, posing a major challenge for cardiac repair following injury such as myocardial infarction (MI). Despite significant advances over the past decade, many strategies for promoting cardiac regeneration have faced limitations, underscoring the need to identify novel molecular pathways and targets. Pyruvate kinase muscle isoform 2 (PKM2), a key metabolic enzyme, has emerged as a compelling candidate in this context due to its multifaceted roles in cellular metabolism, proliferation, redox balance, angiogenesis, and master gene regulator in repair. Recent studies highlight the critical function of PKM2 in cardiac repair and regeneration. PKM2 not only promotes the proliferation of CMs but also protects the heart from oxidative stress by redirecting glycolytic intermediates toward the pentose phosphate pathway (PPP), thereby increasing nicotinamide adenine dinucleotide phosphate (NADPH) levels, reducing reactive oxygen species (ROS), and minimizing DNA damage. Moreover, PKM2 interacts with key signaling molecules, including β-catenin, hypoxia-inducible factor 1α (HIF-1a), and checkpoint kinase 1 (CHK1), to promote CM cell cycle reentry, angiogenesis, and enhanced cell survival. Collectively, these multifaceted actions highlight PKM2 as both a metabolic and signaling hub in cardiac repair by promoting myocardial remuscularization, protection, and revascularization and position PKM2 as a promising therapeutic. This review explores the diverse roles of PKM2 in myocardial repair and discusses its potential as a novel avenue for advancing regenerative therapies in cardiovascular medicine. Full article

Alpinetin, a distinctive plant-derived dihydroflavonoid from cardamom seeds, represents an under-explored chemical scaffold compared to common flavonoids like quercetin or kaempferol. While many flavonoids have shown general cardioprotective potential, the structural specificity of alpinetin may confer unique pharmacological advantages. Inspired by its historical use in traditional Chinese medicine for cardiac discomfort, this study systematically investigated its efficacy against acute myocardial infarction (AMI). In a rat AMI model, alpinetin demonstrated superior infarct size reduction and functional recovery relative to other tested flavonoids. It significantly attenuated key AMI pathologies—including inflammatory infiltration, CD68+ macrophage activation, IL-6/TNF-α release, collagen deposition, and cardiomyocyte apoptosis—more effectively than common flavonoid benchmarks. Mechanistically, alpinetin selectively targeted the TLR4/MyD88/NF-κB signaling axis with notable potency, a pathway not robustly modulated by other flavonoids in the screening. These findings not only validate the traditional wisdom of cardamom but also establish alpinetin as a structurally and mechanistically distinct flavonoid with high translational promise, offering a new candidate for the targeted treatment of ischemic heart disease. Full article

Myocardial infarction triggers limited repair in adult mammals but robust regeneration in zebrafish. Epigenetic regulation and immune responses are recognized as critical for successful regeneration. However, the molecular links between these processes have not been fully elucidated. By performing single-cell RNA sequencing of zebrafish ventricular cardiomyocytes after injury, we identified a regeneration-induced immunomodulatory cluster that specifically expressed the histone demethylase gene kdm7aa. Functional perturbations, including CRISPR/Cas9-mediated kdm7aa mutation and pharmacological inhibition of Kdm7aa activity using TC-E5002, impaired cardiac regeneration. Bulk RNA sequencing showed that kdm7aa drives an inflammatory transcriptional program, prominently activating chemokines such as cxcl8a and cxcl19 that coordinate immune cell recruitment. Cross-species analyses revealed injury-induced Kdm7a upregulation in regeneration-competent neonatal mouse hearts but not in adult mouse or human hearts. These data identified Kdm7aa as a regeneration-induced epigenetic regulator that enabled cardiomyocytes to adopt a transient immune-activating phenotype, linking histone demethylation to chemokine signaling and suggesting a potential therapeutic strategy to enhance mammalian cardiac repair. Full article

Circular RNAs (circRNAs) have emerged as crucial cardiovascular regulators through gene expression modulation, microRNA sponging, and protein interactions. Their covalently closed structure confers exceptional stability, making them detectable in blood and tissues as potential biomarkers. This review explores current research examining circRNAs across cardiovascular diseases, including atherosclerosis, myocardial infarction, and heart failure. We highlight the control that circRNA exerts over endothelial function, smooth muscle switching, inflammatory recruitment, and cardiomyocyte survival. Key findings distinguish frequently disease-promoting circRNAs (circANRIL, circHIPK3) from context-dependent regulators (circFOXO3). Compartment-specific controllers include endothelial stabilizers (circGNAQ), smooth muscle modulators (circLRP6, circROBO2), and macrophage regulators (circZNF609), functioning as tunable rheostats across vascular compartments. Overall, the literature suggests that circRNAs represent promising tools in two translational avenues: (i) blood-based multimarker panels for precision diagnosis and (ii) targeted modulation of pathogenic circuits. Clinical translation will require precise cell-type targeting, efficient delivery to cardiovascular tissues, and rigorous mitigation of off-target effects. Full article

Circulating heart-reactive autoantibodies (aAbs) detected in a variety of heart diseases (e.g., myocarditis, dilated cardiomyopathy, and myocardial infarction) have been associated with the progression of heart failure and a poor prognosis. However, the underlying mechanisms remain largely unknown. We investigated the effects of murine plasma containing aAbs against cardiac troponin I (cTnI) on neonatal rat cardiomyocytes (NRCMs). An autoimmune response to cTnI in A/J mice was induced, and anti-cTnI-aAbs were quantified. After 21 days, cardiac function, inflammation, fibrosis, and apoptosis were evaluated. In complementary in vitro liquid biopsy experiments, NRCMs were incubated with murine plasma containing high anti-cTnI-aAb levels or corresponding controls. Morphological phenotyping was performed using the C-MORE fluorescent image-based analysis workflow. Immunization with cTnI resulted in high anti-cTnI-aAb production, followed by myocardial inflammation, fibrosis, and impaired ejection fraction. NRCMs exposed to anti-cTnI-aAb-containing plasma showed reduced cell size, altered shape and radius, and elevated rate of dead cells in cell cycle analysis (p < 0.01, for 20% plasma). Together, these findings suggest a direct interaction of anti-cTnI-aAbs on cardiomyocytes, likely promoting adverse myocardial remodeling in vivo. Full article