RESUMO
Objective To explore whether miR-29a can influence the phenotypic transformation of vascular smooth muscle cells (VSMCs) by inhibiting expression of Kruppel-like factor 4 (KLF4). Methods Rat VSMCs were cultured primarily. The luciferase reporter system was used to verify whether KLF4 is the target gene of miR-29a. VSMCs were divided into miR-29a-transfected expression plasmid group, transfection-negative expression plasmid group, and no-transfection group. The expression of KLF4 and VSMC contractile phenotype protein levels were determined by Western blotting. The proliferation of VSMCs was analyzed by3H thymidine-incorporation assay. Results The lucierase activity was significantly decreased in wild-type KLF4 luciferase report gene and miR-29a expression plasmid co-transfection group. The KLF4 protein expression level (0.36 ± 0.02) was significantly lower in miR-29a-transfected expression plasmid group than that in untransfected and transfection-negative expression plasmid group (1.52 ± 0.06, 1.55 ± 0.05, respectively, P<0.01). Meanwhile, compared with untransfected and transfection-negative expression plasmid groups, the contractile phenotype associated protein SM-MHC, SM-22α, calponin expression levels were increased, while the proliferation capability was decreased in miR-29a-transfected expression plasmid group. Conclusion MiR-29a targets KLF4 and inhibits its expression, thus maintains contractile phenotype of VSMCs, and reduces the cell proliferation ability.