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

Abstract

Rationale: Human 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. Objectives: The purpose of this study is to determine the role of KDM5 in iPSC-CM maturation. Methods and Results: Immunoblot 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. Conclusions: KDM5 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.

c-JUN is a barrier in hESC to cardiomyocyte transition

“…Recently, a study published in Exp Mol Med suggested that inhibiting KDM5A could ameliorate pathological cardiac fibrosis ( 37 ). However, another study submitted to BioRxiv ( 38 Preprint ) suggests KDM5A could regulate cardiomyocyte maturation by promoting fatty acid oxidation, oxidative phosphorylation, and myofibrillar organization. Those studies indicate a complex role for KDM5 in regulating cardiomyocyte cell fate decision and maturation.…”

Fueling cardiac myocyte proliferation

“…This difference can be attributed to the non-cell autonomous effects leading to lipotoxicity [5] as proposed by Li et al [3] . Furthermore, in another study by Ghosh et al [6] , skeletal muscle-specific deletion of CPT1B resulted in reduced α-KG, contrary to a substantial increase in α-KG as seen by Li et al [3] . Therefore, to unequivocally rule out any deleterious effects in CM specific Cpt1b knockout mice, a long-term cardiac function and survival analysis is warranted.…”

“…Therefore, to unequivocally rule out any deleterious effects in CM specific Cpt1b knockout mice, a long-term cardiac function and survival analysis is warranted. Recent studies have documented the role of the KDM5 family of proteins in the maturation of cardiac myocytes [ 7 ] . It was shown that the levels of KDM5 gradually decrease during the maturation of CM and are negligible in the mature adult CM.…”

“…Recent studies have documented the role of the KDM5 family of proteins in the maturation of cardiac myocytes [ 7 ] . It was shown that the levels of KDM5 gradually decrease during the maturation of CM and are negligible in the mature adult CM.…”

Epigenetic regulation of heart failure

“…Our recent study demonstrated that inhibiting KDM5 in induced pluripotent stem cell derived cardiomyocytes promotes their maturity. This maturation program is facilitated by the KDM5 s through the regulation of sarcomeric and OXPHOS genes [32 ▪▪ ]. KDM5 s thus epigenetically regulate the developmental gene program by suppressing maturation and promoting fetal gene expression.…”