Cardiomyocyte-derived USP20 mitigates myocardial ischemia/reperfusion injury through deubiquitinating GRP78.
Myocardial ischemia/reperfusion (I/R) injury remains a major clinical challenge characterized by cardiomyocyte loss and adverse remodeling after reperfusion. Ubiquitin-Specific Peptidase 20 (USP20), a deubiquitinase involved in cellular stress responses, has not been fully characterized in the ischemic heart. This study aimed to investigate the function and mechanism of cardiomyocyte-derived USP20 in myocardial I/R injury.
Myocardial I/R models and hypoxia/reoxygenation (H/R)-treated cardiomyocytes were used to evaluate USP20 expression and function. Single-cell transcriptomic analysis, cardiomyocyte-specific USP20 knockout, and USP20 overexpression models were applied. Co-immunoprecipitation, LC-MS/MS, ubiquitination assays, site-directed mutagenesis, and rescue experiments were performed to define the underlying mechanism.
USP20 expression was markedly decreased in I/R-injured mouse hearts and H/R-treated cardiomyocytes, and USP20 was predominantly localized in cardiomyocytes. Cardiomyocyte-specific USP20 deletion aggravated myocardial injury, adverse cardiac remodeling, and cardiac dysfunction after I/R, whereas USP20 overexpression conferred significant cardioprotection. Mechanistically, USP20 directly interacted with glucose-regulated protein 78 (GRP78) and removed K63-linked polyubiquitin chains from GRP78 at K602 through its C154 active site. This deubiquitination activated GRP78, promoted adaptive endoplasmic reticulum stress responses, and reduced myocardial injury.
These findings identify a previously unrecognized USP20-GRP78 regulatory axis that regulates endoplasmic reticulum stress responses and limits myocardial damage during I/R. USP20 may represent a potential therapeutic target for myocardial I/R injury.
Myocardial I/R models and hypoxia/reoxygenation (H/R)-treated cardiomyocytes were used to evaluate USP20 expression and function. Single-cell transcriptomic analysis, cardiomyocyte-specific USP20 knockout, and USP20 overexpression models were applied. Co-immunoprecipitation, LC-MS/MS, ubiquitination assays, site-directed mutagenesis, and rescue experiments were performed to define the underlying mechanism.
USP20 expression was markedly decreased in I/R-injured mouse hearts and H/R-treated cardiomyocytes, and USP20 was predominantly localized in cardiomyocytes. Cardiomyocyte-specific USP20 deletion aggravated myocardial injury, adverse cardiac remodeling, and cardiac dysfunction after I/R, whereas USP20 overexpression conferred significant cardioprotection. Mechanistically, USP20 directly interacted with glucose-regulated protein 78 (GRP78) and removed K63-linked polyubiquitin chains from GRP78 at K602 through its C154 active site. This deubiquitination activated GRP78, promoted adaptive endoplasmic reticulum stress responses, and reduced myocardial injury.
These findings identify a previously unrecognized USP20-GRP78 regulatory axis that regulates endoplasmic reticulum stress responses and limits myocardial damage during I/R. USP20 may represent a potential therapeutic target for myocardial I/R injury.
Authors
Cheng Cheng, Zhong Zhong, Ying Ying, Huang Huang, Yang Yang, Zhang Zhang, Huang Huang, Zhang Zhang, Chen Chen, Fan Fan, Zhang Zhang, Zheng Zheng, Ye Ye, Lin Lin, Huang Huang, Zhao Zhao, Dai Dai
View on Pubmed