FTO Stabilizes MIS12 to Inhibit Vascular Smooth Muscle Cell Senescence in Atherosclerotic Plaque.

PURPOSE: Atherosclerosis is the main cause of atherosclerotic cardiovascular disease (CVD). Here, we aimed to uncover the role and mechanisms of fat mass and obesity-associated genes (FTO) in the regulation of vascular smooth muscle cell (VSMC) senescence in atherosclerotic plaques.

METHODS: ApoE-/- mice fed a high-fat diet (HFD) were used to establish an atherosclerotic animal model. Immunohistochemistry, and the staining of hematoxylin-eosin, Oil Red O, Sirius red, and Masson were performed to confirm the role of FTO in atherosclerosis in vivo. Subsequently, FTO expression in primary VSMCs is either upregulated or downregulated. Oxidized low-density lipoprotein (ox-LDL) was used to treat VSMCs, followed by EdU staining, flow cytometry, senescence-associated β-galactosidase (SA-β-gal) staining, immunofluorescence, telomere detection, RT-qPCR, and Western blotting to determine the molecular mechanisms by which FTO inhibits VSMC senescence.

RESULTS: Decreased FTO expression was observed in progressive atherosclerotic plaques of ApoE-/- mice fed with HFD. FTO upregulation inhibits atherosclerotic lesions in mice. FTO inhibits VSMC aging in atherosclerotic plaques by helping VSMC withstand ox-LDL-induced cell cycle arrest and senescence. This process is achieved by stabilizing the MIS12 protein in VSMC through a proteasome-mediated pathway.

CONCLUSION: FTO inhibits VSMC senescence and subsequently slows the progression of atherosclerotic plaques by stabilizing the MIS12 protein.