Biology subjects

Gurha, P.

Publications and source records attributed to Gurha, P..

3 recordsLinked to original sources

bioRxiv2026

The Epigenetic Regulator Histone Demethylase KDM5A is Activated and Pathogenic in a Mouse Model of Heart Failure

Heart failure is a complex disease characterized by the dysregulation of gene expression that culminates in cardiac dysfunction. Epigenetic regulators play a critical role in control of transcription and are increasingly implicated in the pathogenesis of heart failure. We recently showed that the histone demethylase KDM5A is reactivated in the heart of human patients and mouse models of heart failure. However, its pathogenic role in heart failure remained unknown. Utilizing a mouse model of heart failure caused by the deletion of the Lmna gene in cardiomyocytes and referred to as LMNA-cardiomyopathy (LMNA-CMP), we show that KDM5A is activated, and expression levels of genes involved in myocyte structure and function, including oxidative phosphorylation (OXPHOS), are suppressed. To determine the pathogenic role of KDM5A in heart failure, the Kdm5a gene was specifically deleted in cardiomyocytes in LMNA-CMP mice (Myh6-Cre:LmnaF/F:Kdm5aF/F). The deletion of the Kdm5a gene improved cardiac function, prolonged survival, attenuated fibrosis, and reduced cell death in LMNA-CMP mice. Transcriptome analysis showed that the deletion of the Kdm5a gene restored the expression of over 1,400 dysregulated genes, including those involved in fatty acid metabolism, myogenesis, and OXPHOS in the Myh6-Cre:LmnaF/F:Kdm5aF/F mice. Genome-wide profiling of the epigenetic histone mark H3 lysine 4 trimethylation (H3K4me3), the main target of KDM5A, by CUT&RUN assay showed that deletion of the Kdm5a gene partially restored H3K4me3 deposits at loci encoding cardiac transcription factors and metabolic regulators, including Tbx5 and Esrrg, with concomitant rescue of their downstream targets. These findings identify KDM5A as a key epigenetic regulator of cardiomyocyte gene expression and uncover a mechanistic role for KDM5A in the pathogenesis of heart failure.

genetics↗

bioRxiv2023

Histone demethylase KDM5 regulates cardiomyocyte maturation by promoting fatty acid oxidation, oxidative phosphorylation, and myofibrillar organization

RationaleHuman pluripotent stem cell-derived CMs (iPSC-CMs) are a valuable tool for disease modeling, cell therapy and to reconstruct the CM maturation process and identify, characterize factors that regulate maturation. The transition from immature fetal to adult CM entails coordinated regulation of the mature gene programming, which is characterized by the induction of myofilament and OXPHOS gene expression among others. Recent studies in Drosophila, C. elegans, and C2C12 myoblast cell lines have implicated the histone H3K4me3 demethylase KDM5 and its homologs, as a potential regulator of developmental gene program and mitochondrial function. We speculated that KDM5 may potentiate the maturation of iPSC-CMs by targeting a conserved epigenetic program that encompass mitochondrial OXPHOS and other CM specific maturation genes. ObjectivesThe purpose of this study is to determine the role of KDM5 in iPSC-CM maturation. Methods and ResultsImmunoblot analysis revealed that KDM5A, B, and C expression was progressively downregulated in postnatal cardiomyocytes and absent in adult hearts and CMs. Additionally, KDM5 proteins were found to be persistently expressed in iPSC-CMs up to 60 days after the onset of myogenic differentiation, consistent with the immaturity of these cells. Inhibition of KDM5 by KDM5-C70 -a pan-KDM5 inhibitor-resulted in differential regulation of 2,372 genes including upregulation of Fatty acid oxidation (FAO), OXPHOS, and myogenic gene programs in iPSC-CMs. Likewise, genome-wide profiling of H3K4me3 binding sites by the CUT&RUN assay revealed enriched H3K4me3 peaks at the promoter regions of FAO, OXPHOS, and sarcomere genes. Consistent with the chromatin and gene expression data, KDM5 inhibition led to increased expression of multiple sarcomere proteins, enhanced myofibrillar organization and improved calcium handling. Furthermore, inhibition of KDM5 increased H3K4me3 deposits at the promoter region of the ESRRA gene, which is known to regulate OXPHOS and cardiomyocyte maturation, and resulted in its increased RNA and protein levels. Finally, KDM5 inhibition increased baseline, peak, and spare oxygen consumption rates in iPSC-CMs. ConclusionsKDM5 regulates the maturation of iPSC-CMs by epigenetically regulating the expression of ESRRA, OXPHOS, FAO, and sarcomere genes and enhancing myofibril organization and mitochondrial function.

genomics↗

bioRxiv2023

Genetic Inactivation of Beta-Catenin Attenuates and Its Activation Aggravates Desmoplakin Cardiomyopathy

AimMutations in the DSP gene encoding desmoplakin, a constituent of the desmosomes at the intercalated discs (IDs), cause a phenotype that spans arrhythmogenic cardiomyopathy (ACM) and dilated cardiomyopathy (DCM). It is typically characterized by biventricular enlargement and dysfunction, severe myocardial fibrosis, cell death, and arrhythmias. The canonical WNT (cWNT)/{beta}-catenin signaling pathway is implicated in the pathogenesis of ACM. Given that {beta}-catenin, an indispensable co-transcriptional regulator of the cWNT pathway, is also a member of the IDs, we genetically inactivated or activated {beta}-catenin to determine its role in the pathogenesis of the desmoplakin cardiomyopathy. Methods and ResultsThe Dsp gene was conditionally deleted in cardiac myocytes concomitant with the genetic inactivation or activation of {beta}-catenin using the tamoxifen-inducible MerCreMer mice. Inactivation and activation of {beta}-catenin were achieved upon deletion of its transcriptional domain and degrons, respectively. Analysis of cardiac myocytes transcripts and proteins showed marked dysregulation of the cWNT/{beta}-catenin pathway in the DSP-deficient mouse cardiac myocytes (Myh6-McmTam:DspF/F), as indicated by increased expression of cWNT/{beta}-catenin targets along with its inhibitors and isoforms of its key co-effectors. Genetic inactivation of {beta}-catenin in the Myh6-McmTam:DspF/F mice prolonged survival, improved cardiac function, reduced cardiac arrhythmias, and attenuated myocardial fibrosis, and cell death caused by apoptosis, necroptosis, pyroptosis, i.e., PANoptosis, whereas its activation had the opposite effects. Inactivation of {beta}-catenin was associated with partial restoration of the suppressed genes involved in OXPHOS, whereas its activation has the opposite effect. The beneficial effects were independent of the changes in the transcript levels of the cWNT target genes. ConclusionThe cWNT/{beta}-catenin was markedly dysregulated in the cardiac myocytes from a mouse model of DC. Inactivation of {beta}-catenin attenuated the phenotype partly through the recovery of OXPHOS genes whereas its activation had deleterious effects. The findings suggest suppression of {beta}-catenin might be beneficial in desmoplakin-cardiomyopathy. SummaryGenetic inactivation of {beta}-catenin improved desmoplakin cardiomyopathy, in part through the restoration of expression of genes involved in oxidative phosphorylation, whereas its activation was deleterious.

genetics↗