JOSD2 inhibits angiotensin II-induced vascular remodeling by deubiquitinating and stabilizing SMAD7

Abstract

Increased level of angiotensin II (Ang II) plays a central role in the development of hypertensive vascular remodeling. In this study, we identified the deubiquitinating enzyme Josephin domain-containing protein 2 (JOSD2) as a protective factor and investigated its molecular mechanism in Ang II-induced vascular remodeling. First, we found that JOSD2 was upregulated in aortic smooth muscle cells, but not in endothelial cells of Ang II-challenged mouse vascular tissues. Whole-body knockout of JOSD2 significantly deteriorated Ang II-induced vascular remodeling in mice. Conversely, Ang II-induced vascular remodeling was reversed by vascular smooth muscle cell (VSMC)-specific JOSD2 overexpression. In vitro, JOSD2 deficiency aggravated Ang II-induced fibrosis, proliferation, and migration VSMCs, while these changes were reversed by JOSD2 overexpression. RNA-seq analysis showed that the protective effects of JOSD2 in VSMCs were related to the TGFβ-SMAD pathway. Furthermore, the LC-MS/MS analysis identified SMAD7, a negative regulator in the TGFβ-SMAD pathway, as the substrate of JOSD2. JOSD2 specifically bound to the MH1 domain of SMAD7 to remove the K48-linked ubiquitin chains from SMAD7 at lysine 220 to sustain SMAD7 stability. Taken together, our finding reveals that the JOSD2-SMAD7 axis is critical for relieving Ang II-induced vascular remodeling and JOSD2 may be a novel and potential therapeutic target for hypertensive vascular remodeling.

Keywords: JOSD2; SMAD7; angiotensin II; ubiquitination; vascular remodeling.