Abstract: Object To investigate the role of miR-26a played in the PDGF-BB induced VSMC phenotypic transformation. Methods Primary mouse aortic VSMCs were divided into blank control group, anti-miR-26a group, PDGF-BB+anti-miR-control group and PDGF-BB+anti-miR-26a group, which were treated with Ad-GFP, anti-miR-26a, PDGF-BB+anti-miR-control and PDGF-BB+anti-miR-26a respectively. Then VSMCs phenotypic transformation was observed. The mRNA and protein expression of alpha-SMA, calponin, SM-MHC and VSMC differentiation marker genes, were detected by RT-PCR and Western blot, respectively. The expression of miR-26a was determined by real-time PCR also. Results Compare with control group, PDGF-BB induced a dose-dependent and time-dependent suppression of the mRNA and protein levels of α-SMA, calponin and SM-MHC(p＜0.05); PDGF-BB significantly increased the miR-26a expression in VSMCs(p＜0.05); Inhibition of miR-26a partly abrogated the depression of PDGF-BB on alpha-SMA, calponin and SM-MHC(p＜0.05). Conclusions PDGF-BB increases the expression of miR-26a in VSMCs. MiR-26a promotes cell proliferation and migration of VSMCs, miR-26a may play a critical role in PDGF-BB induced VSMCs phenotype transformation.

Key words: Key word: miR-26a, VSMCs, phenotypic switch, PDGF-BB