USP7 cardiomyocyte specific knockout causes disordered mitochondrial biogenesis and dynamics and early neonatal lethality in mice

Ubiquitination is an enzymatic modification involving ubiquitin chains, that can be reversed by deubiquitination (DUB) enzymes. Ubiquitin-specific protease 7 (USP7), which is also known as herpes virus-associated ubiquitin-specific protease (HAUSP), has been shown to play a vital role in cardiovascular diseases. However, the underlying molecular mechanism by which USP7 regulates cardiomyocyte function has not been reported. To understand the physiological function of USP7 in the heart, we constructed cardiomyocyte-specific USP7 conditional knockout mice. We found that homozygous knockout mice died approximately three weeks after birth, while heterozygous knockout mice grew normally into adulthood. Severe cardiac dysfunction, hypertrophy, fibrosis, and cell apoptosis were observed in cardiomyocyte-specific USP7 knockout mice, and these effects were accompanied by disordered mitochondrial dynamics and cardiometabolic-related proteins. In summary, we investigated changes in the growth status and cardiac function of cardiomyocyte-specific USP7 knockout mice, and preliminarily explored the underlying mechanism. [Display omitted] •We found that homozygous cardiomyocyte-specific USP7 knockout leads to the death of mice in neonatal period.•Severe cardiac dysfunction and structure impairments occur in homozygous cardiomyocyte-specific USP7 knockout mice.•Cardiomyocyte-specific knockout of USP7 leads to cardiomyocyte apoptosis and myocardial mitochondrial dysfunction in mice.