Circ_ROBO2/miR-149 Axis Promotes the Proliferation and Migration of Human Aortic Smooth Muscle Cells by Activating NF-κB Signaling

Atherosclerosis is the leading global cause of mortality. The occurrence of coronary artery disease (CAD) is regulated by a diversity of pathways, including circRNAs. However, the potential mechanisms of circRNAs in CAD remain unclear. Here, qRT-PCR was used to examine the expressions of miR-149 and circ_ROBO2. Their influences on cell proliferation, migration, and apoptosis were measured by CCK-8, trans­well, and flow cytometry assays, respectively. The protein levels of p-IκBα and NF-κB p65 were examined using western blot. The molecular interactions were validated using dual luciferase reporter and RNA pull-down assays. The expression patterns of circ_ROBO2 and miR-149 in CAD patients and PDGF-BB-treated human aortic smooth muscle cells (HASMCs) were upregulated and downregulated, respectively. Knockdown of circ_ROBO2 could markedly inhibit the capabilities of proliferation and migration, enhance the apoptotic rate, and suppress NF-κB signaling in PDGF-BB-treated HASMCs. Mechanistically, circ_ROBO2 acted as a sponge of miR-149 to activate TRAF6/NF-κB signaling. Rescue studies demonstrated that neither silencing miR-149 nor activation of NF-κB signaling obviously abolished the biological roles of circ_ROBO2 knockdown in PDGF-BB treated-HASMCs. This discovery elucidated a functional mechanism of circ_ROBO2 in CAD, suggesting that circRNAs serve a vital role in the progression of CAD.