MicroRNA-133b regulates the growth and migration of vascular smooth muscle cells by targeting matrix metallopeptidase 9.

Atherosclerosis is a systemic disease affecting the whole arterial tree of the human body, and it is the leading cause of cardiovascular diseases.Vascular smooth muscle cells (VSMCs) have been identified to play a key role in the development of atherosclerosis. MicroRNAs (miRNAs) are a group of endogenous small non-coding RNAs, and they play a critical role in many biological processes including regulating cell proliferation, migration and apoptosis. However, till now, the expression and role of miR-133b in atherosclerosis remain largely unknown. Therefore, our purpose was to investigate the expression and role of miR-133b in atherosclerosis and to explore the underlying mechanism. The results showed that miR-133b was down-regulated in the blood and vascular plaque tissues of rabbits with atherosclerosis. Matrix metallopeptidase 9 (MMP-9) was a direct target of miR-133b. In addition, our data indicated that miR-133b mimic could significantly inhibit rVSMC cell proliferation activity, migration ability and induce cell apoptosis compared with the control group, and all these effects were reversed by MMP-9-plasmid. Taken together, these findings highlight an important role for miR-133b/MMP-9 axis in atherosclerosis. And miR-133b might be a valuable clinical marker and therapeutic target for atherosclerosis.