EPAS1 induction drives myocardial degeneration in Desmoplakin-cardiomyopathy [RNA-seq]

Arrhythmogenic cardiomyopathy (ACM) is frequently attributed to desmosomal mutations, such as those in the desmoplakin (DSP) gene. Patients with DSP- cardiomyopathy are predisposed to myocardial degeneration and arrhythmias. Despite advancements, the underlying molecular mechanisms remain incompletely understood, thus limiting therapeutic options. Here, we employed spatial transcriptomics on an explanted heart from a patient with a pathogenic DSP variant. Our transcriptional analysis revealed endothelial PAS domain-containing protein 1 (EPAS1) as a potential regulator of mitochondrial homeostasis in stressed cardiomyocytes. Elevated EPAS1 levels were associated with mitochondrial dysfunction and hypoxic stress in both human-relevant in vitro ACM models and additional explanted hearts with genetic cardiomyopathy. Collectively, cardiomyocytes bearing pathogenic DSP variants exhibit mitochondrial dysfunction, increased apoptosis, and impaired contractility, which are linked to the increased EPAS1 levels. These findings implicate EPAS1 as a key regulator of myocardial degeneration in DSP-cardiomyopathy, which expand to other forms of ACM. Overall design: To elucidate roles of EPAS1 in cardiomyopathy, EPAS1 was suppressed in WT iPSC-derived cardiomyocytes using siRNA, or EPAS1 was overexpressed using AAV6 in DSP p.Arg1113X/WT iPSC-derived cardiomyocytes.