Cardiomyocyte-derived USP13 protects hearts from hypertrophy via deubiquitinating and stabilizing STAT1 in male mice.

Cardiac hypertrophy leads to ventricular dysfunction and heart failure. Deubiquitinating enzymes are responsible for preserving the substrate protein stability and are essential to myocardial hypertrophy. In this study, we aimed to explore the role and regulatory mechanism of a cardiomyocyte-derived deubiquitinating enzyme, USP13, in cardiac hypertrophy. Here we show that USP13 was increased in hypertrophic myocardium and was mainly distributed in cardiomyocytes. Cardiomyocyte-specific Usp13 knockout aggravated TAC or Ang II-induced myocardial hypertrophy and dysfunction in male mice. Correspondingly, USP13 overexpression by AAV9 in hearts exerted a therapeutic impact on cardiac hypertrophy in male mice. Mechanistically, we identified STAT1 as a substrate of USP13 through interactome analysis. USP13 deubiquitinated STAT1, thereby reducing its degradation. Subsequently, USP13 promoted the STAT1-targeted Nppb gene transcription and enhanced mitochondrial function in cardiomyocytes. This study illustrated a beneficial effect of USP13 in hypertrophic cardiomyocytes and identified a cardiomyocyte-specific USP13-STAT1 axis in regulating cardiac hypertrophy.