The Role Of MicroRNA-27a In Ang ?-induced Proliferation And Migration Of Vascular Smooth Muscle Cells And Its Mechanism

Background:Vascular smooth muscle cells(VSMCs)display two phenotypes: contractile and synthetic?Angiotensin ?(Ang ?)can induce proliferation,migration and secretion of extracellular matrix proteins of VSMCs.Micro RNAs(miRNAs)are small,conserved,~21-mer RNAs that regulate the gene expression through the regulation of mRNA degradation and post-transcriptional control.However,the role of miRNAs in the proliferation and migration of VSMCs remain to be determined.Objective: To investigate the role of micro RNA-27 a in Ang ?-induced proliferation and migration of VSMCs and the molecular mechanism.Methods: Mouse primary VSMCs were treated with 100 nmol Ang ? for 0,6,12,and 24 hours.VSMCs were transfected with miRNA blank vector,miR-27 a inhibitor or miR-27 a mimetic for 24 hours and then treated with Ang ?(100 nmol)for an additional 24 hours.Cell proliferation was detected by CCK-8 kit.Cell migration was measured by cell scratch assay.Real-time quantitative PCR(q PCR)analysis was used to examine the transfection efficiency,and the expression levels of miR-27 a and ?-SMA.Moreover,Target Scan 6.2 was used to predict the potential target genes of miR-27 a.The plasmids carrying wild-type(WT)or mutant ?-SMA 3'-UTR were co-transfected with miR-27 a mimic in HEK-293 cells.Dural-luciferase reporter assay was performed.q PCR and Western blot were used to detect the effects of miR-27 a knockdown and miR-27 a overexpression on the expression of ?-SMA at both mRNA and protein expression levels in VSMCs.Results: Ang ? treatment for 6 hours time-dependently induces the proliferation and migration of VSMCs.Compared with the NC group,miR-27 a mRNA expression was time-dependently increased,but ?-SMA mRNA expression was time-dependently decreased in SMCMs after 6 hours of Ang ? treatment.Compared with the NC group,transfection of miR-27 a inhibitor significantly reduces the expression of miR-27 a,and inhibited the proliferation and migration of VSMCs after Ang ? stimulation.In contrast,transfection of miR-27 a mimic further enhanced Ang ? response.The dual luciferase report assay revealed that transfection of miR-27 a mimic markedly attenuated luciferase activity.q PCR and Western blot analysis confirmed the levels of ?-SMA mRNA and protein were significantly increased by miR-27 a inhibitor,but was further decreased by miR-27 a mimic.Conclusion :These results indicate that miR-27 a is involved in the angiotensin ?-induced proliferation and migration of vascular smooth muscle cells by targeting?-SMA,suggesting that miR-27 a is likely to be a potential therapeutic target for cardiovascular disease.