Astragalus Inhibits Epithelial-to-Mesenchymal Transition of Peritoneal Mesothelial Cells by Down-Regulating β-Catenin

The epithelial-to-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is a crucial event in the induction of peritoneal fibrosis (PF), in which canonical Wnt/β-catenin signaling participates. Smads signaling is reported to interact with β-catenin and synergistically regulates EMT. This study was aimed to reveal the effect of Astragalus on β-catenin in EMT of PMCs.To obtain the role of β-catenin in EMT, gene transfer into HMrSV5 cell line and rats has been achieved. After Astragalus treatment, EMT markers and signaling pathway-related indicators were detected by western blotting, immunofluorescence, immunohistochemistry, immunoprecipitation and real time-PCR.β-catenin knockdown suppressed EMT of HMrSV5 cells. Astragalus alleviated EMT of PMCs characterized by increased E-cadherin and decreased α-SMA and Vimentin. In rat model of peritoneal dialysis (PD), Astragalus attenuated peritoneal thickening and fibrosis. Astragalus down-regulated β-catenin by stabilizing the Glycogen synthase kinase-3β (GSK-3β)/β-catenin complex and further inhibited the nuclear translocation of β-catenin. Meanwhile, Astragalus down-regulated β-catenin by enhancing Smad7 expression. Silencing Smad7 antagonized the EMT-inhibitory effect of Astragalus.Astragalus inhibits EMT of PMCs by down-regulating β-catenin. The modulation of β-catenin in peritoneum can be a novel tool to prevent PF.