Myocyte Enhancer Factor 2A Regulates Hydrogen Peroxide-Induced Senescence of Vascular Smooth Muscle Cells Via microRNA-143.

Abstract

Myocyte enhancer factor 2A (MEF2A) is involved in vascular smooth muscle cell (VSMC) proliferation, migration, and senescence. MicroRNA-143/145 (miR-143/145), which may be regulated by MEF2A, is known to promote cellular senescence. We hypothesized that MEF2A may promote VSMC senescence via miR-143/145. VSMC senescence was induced by hydrogen peroxide (H(2)O(2)), followed by detection using a senescence-associated β-galactosidase staining kit. The MEF2A protein, mRNA, and miR-143/145 levels in VSMCs were detected using Western blot analysis and SYBR green real-time quantitative PCR, respectively. We further manipulated the expression levels of MEF2A and miR-143 through viral or transient transfection. VSMC proliferation and migration were determined by methylthiazolyldiphenyl-tetrazolium bromide and Millicell chamber, respectively. Both MEF2A and miR-143, but not miRNA-145, were up-regulated in senescent VSMCs. Overexpression of either MEF2A or miR-143 significantly enhanced VSMC senescence, but reduced proliferation and migration. MEF2A knockdown or miR-143 inhibitor suppressed cellular senescence and increased proliferation and migration. We further revealed AKT signaling as a potential miR-143 target, and an induction of miR-143 expression by MEF2A via KLF2. Additionally, overexpression of MEF2A and miR-143 resulted in synergistic effects on promotion of senescence, and MEF2A knockdown and miR-143 reduction by inhibitor had synergistic inhibitory effects. Finally, MEF2A barely promoted VSMC senescence when miR-143 was inhibited, and miR-143 overexpression antagonized the inhibitory effect of MEF2A knockdown on VSMC senescence. Our results revealed a link and interaction between MEF2A and miR-143 and suggested a potential mechanism for MEF2A to regulate H(2)O(2) -induced VSMC senescence.