Abstract P2091: Histone Deacetylase 6 (HDAC6) Inhibitor Improves Stress-Induced Cardiomyocyte Restructuring in Heart Failure with Preserved Ejection Fraction (HFpEF) in a Multimodal Manner Based on Single Nucleus RNA-seq (snRNA-seq) Analyses

Abstract

In the high fat diet (HFD)/L-NAME mouse model of HFpEF, Ranjbarvaziri et al from Tenaya Therapeutics have previously shown that pharmacological inhibition of HDAC6 improves functional and structural cardiac metrics, together with improved oxidative phosphorylation, improved contraction, and reduced fibrosis. Tissue level as well as single cell level transcriptional studies of control, HFD + L-NAME HFpEF, and HFD + L-NAME HFpEF treated with either HDAC6 inhibitor TYA-018 or SGLT2 inhibitor empagliflozin, demonstrated extensive reversal of disease phenotypes in mice treated with TYA-018. Based on snRNA-Seq analyses, we report characterization of cardiomyocyte (CM) subtypes in HFpEF that establish specific and substantial cell-cell interactions with their surrounding fibroblasts and endothelial cells. These interactions initiate CM-subtype-specific signaling cascades, leading to emergence of ‘stressed’ hypoxic CM and hypercontractile CM subtypes. We show that these cell types increase in the HFpEF disease state. The proportion of ‘stressed’ CMs at tissue level corresponds to the worsening cardiac functional measures, and their composing fractions in left ventricle tissue decline and normalize after TYA-018 treatment. These findings suggest HDAC6 inhibition may regulate undesirable HFpEF phenotype characteristics such as dysregulated metabolism, fibrosis and hypertrophy, and also present detailed cell-level evidence of HDAC6 inhibition’s favorable effects in metabolic syndrome.