The de-UFMylating enzyme UFSP2 drives vascular smooth muscle cells phenotypic switching by sustaining the TCF21/ERK pro-survival pathway.

BACKGROUND AND AIMS: To investigate the role of the de-UFMylating enzyme UFSP2, in regulating the phenotypic switching of vascular smooth muscle cells (VSMCs), a critical event in atherosclerosis. METHODS: UFSP2 expression was analyzed in injured mouse arteries (GEO: GSE40637) and human atherosclerotic renal arteries. In vitro studies utilized human aortic SMCs (HASMCs) where UFSP2 was either overexpressed or knocked down (KD) via shRNA. The effects of UFSP2 modulation on VSMCs phenotype (SM22α and α-SMA), proliferation (EdU incorporation), and migration (wound healing and transwell assays) were assessed, alongside PCNA and MMP-2 expression. RNA-seq and Western blotting were used to investigate underlying mechanisms, focusing on the TCF21/ERK signaling pathway. RESULTS: UFSP2 expression was significantly upregulated in both injured mouse arteries and human atherosclerotic arteries. UFSP2 overexpression suppressed the contractile marker SM22α, while its knockdown promoted a contractile phenotype. Functionally, UFSP2-KD blocked PDGF-BB-induced dedifferentiation and markedly inhibited VSMCs proliferation and migration. Mechanistically, UFSP2-KD suppressed the TCF21 and ERK signaling pathway, inhibiting both PDGF-BB-induced TCF21 protein upregulation and ERK1/2 phosphorylation. Furthermore, UFSP2-KD's effect on phenotype was demonstrated to be independent of global UFMylation levels, as direct knockdown of UFM1 similarly promoted a contractile phenotype. CONCLUSIONS: UFSP2 promotes the synthetic, proliferative phenotype of VSMCs by sustaining the TCF21/ERK signaling axis. This study reveals a novel regulatory mechanism for VSMCs phenotype and identifies UFSP2 as a potential therapeutic target for vascular proliferative diseases.