Mouse endothelial OTUD1 promotes angiotensin II‐induced vascular remodeling by deubiquitinating SMAD3

Abstract Understanding the molecular mechanisms of pathological vascular remodeling is important for treating cardiovascular diseases and complications. Recent studies have highlighted a role of deubiquitinases in vascular pathophysiology. Here, we investigate the role of a deubiquitinase, OTUD1, in angiotensin II (Ang II)‐induced vascular remodeling. We detect upregulated OTUD1 in the vascular endothelium of Ang II‐challenged mice and show that OTUD1 deletion attenuates vascular remodeling, collagen deposition, and EndMT. Conversely, OTUD1 overexpression aggravates these pathological changes both in vivo and in vitro . Mechanistically, SMAD3 is identified as a substrate of OTUD1 using co‐immunoprecipitation followed by LC–MS/MS. We find that OTUD1 stabilizes SMAD3 and facilitates SMAD3/SMAD4 complex formation and subsequent nuclear translocation through both K48‐ and K63‐linked deubiquitination. OTUD1‐mediated SMAD3 activation regulates transcription of genes involved in vascular EndMT and remodeling in HUVECs. Finally, SMAD3 inhibition reverses OTUD1‐promoted vascular remodeling. Our findings demonstrate that endothelial OTUD1 promotes Ang II‐induced vascular remodeling by deubiquitinating SMAD3. We identify SMAD3 as a target of OTUD1 and propose OTUD1 as a potential therapeutic target for diseases related to vascular remodeling.