CircRNA LRP6 promotes high-glucose induced proliferation and migration of vascular smooth muscle cells through regulating miR-545-3p/HMGA1 signaling axis

These findings suggest that circRNA LRP6 promotes HG-induced VSMC proliferation and migration through regulating miR-545-3p/HMGA1 signaling axis.

Human VSMCs were cultured under the condition of normal glucose (NG) or high glucose (HG). VSMC viability and proliferation were estimated by CCK-8 and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assays. VSMC migration and invasion were assessed via wound-healing and transwell experiments. Protein expression of HMGA1 was measured in VSMCs using western blot and immunofluorescence analysis. Relative expressions of circLRP6, miR-545-3p, and HMGA1 mRNA were estimated in VSMCs using qRT-PCR. The co-localization of circLRP6 and miR-545-3p was verified by fluorescence in situ hybridization (FISH) analysis. Binding sequence of miR-545-3p in circLRP6 or HMGA1 was predicted using StarBase tool, and verified by RNA immunoprecipitation and dual-luciferase reporter experiments.

The dysfunction of vascular smooth muscle cells (VSMCs) has been revealed to be closely linked with the pathogenesis of cardiovascular diseases in diabetes. Recently, circular RNAs (circRNAs) were found to regulate the behaviors of VSMCs. Here, we attempted to study the role of circLRP6 in VSMCs under diabetes condition.

HG exposure promoted VSMC proliferation, migration and invasion, upregulated the circLRP6 expression, and downregulated HMGA1 expression. Knockdown of circLRP6 or overexpression of miR-545-3p abrogated the HG-caused VSMC proliferation, migration and invasion. CircLRP6 severed as a miR-545-3p sponge, and HMGA1 was targeted by miR-545-3p. MiR-545-3p inhibitor blocked the suppressive effects of si-circLRP6 on VSMC in the presence of HG.