Epalrestat induces cell proliferation and migration in endothelial cells via mTOR activation through PI3/Akt signaling

Abstract

Angiogenesis is a major physiological response to ischemia that involves development of new capillaries and collateral circulation from preexisting vessels, and endothelial cell (EC) proliferation and migration are crucial events for this process. Epalrestat, an aldose reductase inhibitor, is used as a therapeutic agent for the treatment of diabetic peripheral neuropathy. We examined the effect of epalrestat on the proliferation and migration of a mouse microvascular endothelial cell line (bEnd3 cells) measured by scratch wound assay and cell proliferation assay. Epalrestat significantly enhanced the proliferation and migration of bEnd3 cells. The addition of epalrestat resulted in the phosphorylation of Akt and p70 S6 kinase (p70S6K), and this effect was attenuated by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K). Rapamycin, a specific inhibitor of the mammalian target of rapamycin (mTOR), inhibited p70S6K phosphorylation only. Both rapamycin and LY294002 inhibited epalrestat-induced proliferation and migration. These data suggest that epalrestat may activate PI3/Akt/mTOR signaling and that this pathway contributes to the proliferation and migration of EC.