Regulation of oxidized LDL-induced proliferation and migration in human vascular smooth muscle cells by a novel circ_0007478/miR-638/ROCK2 ceRNA network

Abstract

Background: Circular RNAs (circRNAs) have been implicated in the pathogenesis of atherosclerosis (AS) and the migration and proliferation of vascular smooth muscle cells (VSMCs) under oxidized low-density lipoprotein (ox-LDL). Here, we defined the exact action of human circ_0007478 in VSMC migration and proliferation induced by ox-LDL. Methods: Human VSMCs (HVSMCs) were exposed to ox-LDL. Circ_0007478, microRNA (miR)-638, and rho-associated protein kinase 2 ( ROCK2) levels were gauged by quantitative real-time PCR (qRT-PCR) and western blot. Cell viability and proliferation were assessed by MTT and EdU assays, respectively. Transwell assays were used to detect cell migration and invasion. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to evaluate the direct relationship between miR-638 and circ_0007478 or ROCK2. Results: Our data indicated that circ_0007478 expression was augmented in AS serum samples and ox-LDL-treated HVSMCs. Depletion of circ_0007478 attenuated HVSMC proliferation, migration, and invasion induced by ox-LDL. Mechanistically, circ_0007478 targeted miR-638 by directly pairing to miR-638. Reduction of miR-638 reversed the effects of circ_0007478 depletion on ox-LDL-evoked proliferation, migration, and invasion in HVSMCs. ROCK2 was a direct miR-638 target and miR-638-mediated inhibition of ROCK2 relieved ox-LDL-evoked HVSMC proliferation, migration, and invasion. Furthermore, circ_0007478 was identified as a competing endogenous RNA (ceRNA) for miR-638 to modulate ROCK2 expression. Conclusion: Our present study establishes an undescribed ceRNA regulatory network, in which circ_0007478 targets miR-638 to upregulate ROCK2, thereby contributing to ox-LDL-induced proliferation and migration in HVSMCs.

Circular RNAs Variously Participate in Coronary Atherogenesis

“…In the vast majority of cases, an increase in the content of circRNA is accompanied by activation of inflammation, oxidative stress, abnormal proliferation and migration of VSMC, and suppression of HUVEC proliferation. An increase in the level of circRNA can lead to an increase in the expression of ICAM-1 and VCAM-1 [ 135 ], lipid metabolism disturbances, the formation of foam cells [ 147 , 148 ], and other manifestations of atherosclerosis. Thus, atherogenesis-related circRNAs, whose expression level is increased with an overall proatherogenic effect, can be biomarkers and targets for CAD therapy.…”