MicroRNA-4487 regulates vascular smooth muscle cell proliferation, migration and apoptosis by targeting RAS p21 protein activator 1

Abstract

Background: Dysregulation of microRNA (miRNA) is involved in the pathogenesis of a variety of diseases, including atherosclerosis (AS). However, the role of miRNA-4487 (miR-4487) in the development of AS is not fully clarified. This study is intended to investigate the regulatory effects of miR-4487 on the proliferation, migration and apoptosis of vascular smooth muscle cells (VSMCs) and the related mechanisms.

Methods: Oxidized low-density lipoprotein (ox-LDL) was employed to induce the dysfunction of VSMCs. Subsequently, miR-4487 expression was detected by quantitative real-time PCR. Afterward, the expression levels of RAS p21 protein activator 1 (RASA1) and apoptosis-related proteins (Bcl-2, Bax, Cleaved caspase 3, Cleaved caspase 9) were detected by Western blotting. The proliferation, migration and apoptosis of VSMCs were then detected by CCK-8, BrdU, Transwell and flow cytometry assays, respectively. Moreover, a dual-luciferase reporter gene assay was executed to verify the targeting between miR-4487 to the RASA1 3'-untranslated region (3'-UTR).

Results: ox-LDL treatment increased miR-4487 expression and decreased RASA1 expression in VSMCs. Additionally, ox-LDL treatment promoted the proliferation and migration of VSMCs, but inhibited apoptosis. Besides, the effects of ox-LDL treatment on the proliferation, migration and apoptosis of VSMCs were attenuated by the transfection of miR-4487 inhibitors. Furthermore, miR-4487 directly targeted the 3'-UTR of RASA1 mRNA and repressed the expression level of RASA1. Also, RASA1 knockdown reversed the effects of miR-4487 inhibition on VSMCs.

Conclusion: MiR-4487 promotes VSMCs viability and migration and inhibits apoptosis by targeting RASA1 in VSMCs, by which it promotes the pathogenesis of AS.

Keywords: Apoptosis; Atherosclerosis; Migration; Proliferation; RASA1; miR-4487.