Inhibitory effects of ursolic acid from Bushen Yijing Formula on TGF-β1-induced human umbilical vein endothelial cell fibrosis via AKT/mTOR signaling and Snail gene

The present study aimed to investigate the functional components from Bushen Yijing Formula and their inhibition of endothelial–mesenchymal transition (EndMT) and fibrosis in human umbilical vascular endothelial cells (HUVECs). HUVEC fibrosis was induced by treatment of transforming growth factor β (TGF-β) as the cellular model. Expression of EndMT biomarker gene and cofactors were determined by quantitative real-time-PCR, western blotting, and immunofluorescence. Angiogenesis capacity of vein endothelial cells was evaluated using tube formation assay. Ursolic acid and drug-contained serum ameliorated EndMT biomarker gene expression changes and angiogenesis capacity suppression induced by TGF-β treatment. Slug, Snail, and Twist gene expression and phosphorylation of mammalian target of rapamycin (mTOR) and AKT altered by TGF-β in HUVECs were suppressed by ursolic acid and drug-contained serum. Treatment with the mTOR signaling pathway inhibitor, rapamycin, inhibited the phosphorylation of mTOR and AKT, decreased Snail and Vimentin protein levels, and increased VE-cad protein levels. Overexpression of Snail gene promoted expression of EndMT-related genes and suppressed angiogenesis in HUVECs, which were attenuated by application of ursolic acid and drug-contained serum. Ursolic acid from Bushen Yijing Formula inhibits human umbilical vein endothelial cell EndMT and fibrosis, mediated by AKT/mTOR signaling and Snail gene expression.