OTUD1 aggravates pathological cardiac hypertrophy through activation of PGAM5-ASK1 signaling pathways

Deubiquitinating enzymes have gained more and more attention in the field of pathological cardiac hypertrophy. In this study, we explored the role of a deubiquitinase, OTUD1, in the transverse aortic constriction (TAC) induced cardiac hypertrophy. We found the upregulation of OTUD1 in heart tissues of TAC mice. OTUD1 overexpression promoted cardiac hypertrophy, cardiac fibrosis and apoptosis. Conversely, OTUD1 depletion alleviated these pathological changes both in vivo and in vitro. Mechanistically, ASK1 was identified as one substrate of OTUD1 using co-immunoprecipitation followed with LC-MS/MS. Interestingly, OTUD1 didn't deubiquitinate ASK1, but increased the phosphorylation level of ASK1 during the process of cardiac hypertrophy. We found that PGAM5, the upper stream regulator of ASK1, was stabilized by OTUD1 in a K63 ubiquitin chain dependent way, which reminded us OTUD1 increased the phosphorylation level of ASK1 by deubiquitinating PGAM5. This study identified the OTUD1-ASK1 axis as a potential therapeutic target for pathological cardiac hypertrophy. Overall design: We performed RNA sequencing analysis on the NRCMs of three Ad-GFP+Ang II groups and three Ad-Otud1+Ang II groups.