17 β -Estradiol inhibits vascular smooth muscle cell migration via up-regulation of striatin protein

Striatin, an estrogen receptor (ER)-interacting protein, plays an important role in estrogens nongenomic actions in vascular endothelial cells. However, the role of striatin in VSMCs is unknown. Here, we investigated the role of striatin in estrogen-regulated VSMCs migration. 17β-Estradiol (E2) at 10 nM largely inhibited VSMCs migration, which was reversed by the silencing of striatin expression. E2 increased striatin protein expression in a dose- and time-dependent manner. ERα agonist PPT, but not ERβ agonist DPN, mimicked the regulatory effect of E2. The regulatory effect of E2 on striatin protein expression was blocked by the pure ER antagonist ICI 182,780 or the mitogen-activated protein kinase inhibitor PD98059, but not by the phosphatidylinositol-3 kinase inhibitor wortmannin or Src inhibitor PP2, suggesting that E2 increased striatin protein expression via extracellular-signal regulated kinase 1/2 (ERK1/2). E2 resulted in phosphorylation of ERK1/2 in a time-dependent manner. The silencing of ERK1/2 largely abolished E2-enhanced striatin expression. Finally, the inhibitory effect of E2 on VSMC migration was reversed by ICI 182,780 or PD98059. Taken together, our results indicate that E2 inhibits VSMC migration by increasing striatin expression via ERα to ERK1/2 pathway, which maybe helpful to understand estrogens anti-atherogenic effect in VSMCs.