Abstract 15753: Comparative Transcriptomics Analysis of Histone (De)acetylases and Cardiac Ion Channels in Human Induced Pluripotent Stem-Cell-Derived Cardiomyocytes vs. the Adult Human Heart

Abstract

Epigenetic regulation is critical for cardiac electrophysiology and pathology. Epigenetic modulators, such as histone deacetylases (HDACs) and histone acetyltransferases (HATs) are known master regulators of gene expression. Recently, novel pharmacological agents, HDAC inhibitors, have been developed as treatments for cancer and immune diseases. The effects of HDAC inhibitors on cardiac ion channels (ICs) are of great interest. To exert specific gene modulation, we used small interfering RNAs against the known HDACs, including sirtuins, and deployed them in human induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs). Follow-up RNAseq data (n = 61) were compared to identically processed and normalized RNAseq data from human left ventricle (LV) from the GTEx database (n = 84). Gene expression of cardiac ICs displayed similar patterns, with some differences. For example, hiPSC-CMs showed upregulated CACNA1C, SLC8A1 and downregulated KCNJ2 and RYR2 compared to the adult LV, most of which are known distinctions (Fig. 1A). Correlative analysis (Fig. 1B) and partial least square regression models helped visualize links between HDACs/HATs, key transcription factors (TFs) and cardiac ICs. Powerful TFs, including MEF2A, GATA4, 6 exerted positive effect on ICs in hiPSC-CM and the adult LV. In the hiPSC-CMs, HDAC1, HDAC10 and SIRT6 were found to be the strongest predictors of the expression of individual cardiac ICs, as revealed by permutation importance. Further studies will involve determination of the role of different cell types using single-cell sequencing data from the adult LV. Our analysis offers new insights about the role of epigenetic modifiers on cardiac electrophysiology and informs the utility of hiPSC-CM as a scalable, experimental model for cardiotoxicity testing of HDAC inhibitors.