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.