TRIM7 promotes proliferation and migration of vascular smooth muscle cells in atherosclerosis through activating c-Jun/AP-1

Atherosclerosis (AS), with associated risk of stroke or cerebrovascular disease, is one of the most common causes of death globally. It has been well established that tripartite motif-containing protein 7 Tripartite Motif-containing 7 (Trim7), as an E3 ubiquitin protein ligase, is involved in protein ubiquitination and thus regulating cellular proliferation. Moreover, TRIM7 is upregulated in advanced carotid AS. However, the detailed mechanism of TRIM7 on regulation of AS remains unclear. In the present study, we firstly discovered that TRIM7 expression was robustly induced in platelet-derived growth factor type BB-treated vascular smooth muscle cells (VSMCs) and human atherosclerotic plaques. Functional approaches established that knockdown of TRIM7 inhibited proliferation and migration of VSMCs, as well as arrested the cell cycle at G1-S, thus suppressing AS progression. Our results also identified that c-Jun/activator protein 1 (AP-1) signaling pathway was activated by TRIM7. Moreover, gain- and loss-of-function studies revealed that TRIM7 could promote proliferation and migration of VSMCs via activation of c-Jun/AP-1 signaling pathway. Finally, by using atherogenic apolipoprotein E-deficient (apoE-/-) C57BL/6 mice with high-fat diet AS model, we demonstrated that interference of TRIM7 could effectively mitigate in vivo AS via inactivation of c-Jun/AP-1 signaling pathway. In general, activation of c-Jun/AP-1 signaling pathway via TRIM7 could be an important mechanism in AS progression, thus shedding light on the development of novel therapeutics to the treatment of the disease.