microRNA-491-5p protects against atherosclerosis by targeting matrix metallopeptidase-9.

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are critical processes that are involved in atherosclerosis. The aim of this study was to explore the role of microRNA-491-5p (miR-491-5p) in the progression of atherosclerosis by regulating the growth and migration of VSMCs. In this study, we showed that the expression of miR-491-5p was downregulated in the atherosclerotic plaque tissues and plasma samples of the patients with atherosclerosis. The bioinformatic analysis and dual-luciferase reporter assay identified that matrix metallopeptidase-9 (MMP-9) was a target gene of miR-491-5p. The results showed a significant upregulation of MMP-9 in the atherosclerotic plaque tissues and plasma samples. Subsequently, the results also showed that downregulation of miR-491-5p significantly promoted the proliferation and migration of VSMCs and inhibited the apoptosis in VSMCs. Furthermore, we detected the effects of miR-491-5p mimic on the growth and migration of VSMCs, and the results illustrated that miR-491-5p mimic could inhibit the proliferation and migration of VSMCs and promote the apoptosis of VSMCs. Notably, MMP-9 plasmid could reverse all the effects of miR-491-5p mimic on VSMCs. Collectively, our study provides the first evidence that miR-491-5p inhibited the growth and migration of VSMCs by targeting MMP-9, which might provide new biomarkers and potential therapeutic targets for atherosclerosis treatment.