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Keywords:

  • epithelial–mesenchymal transition;
  • evodiamine;
  • PPAR-gamma;
  • Smad;
  • TGF-beta1

Abstract

Epithelial–mesenchymal transition (EMT) is involved in renal tubulointerstitial fibrosis. Transforming growth factor (TGF)-beta1 is the main inducer of EMT. Phosphorylation of Smad proteins and PPAR-gamma activation are required for the process of TGF-beta1-induced EMT. Evodiamine possesses anti-inflammatory, anti-obesity, anti-cancer, and anti-nociceptive effects. We have examined the effects of evodiamine in EMT induced by TGF-beta1 and the role of Smad and PPAR-gamma signal pathway in rat renal proximal tubular epithelial (NRK52E) cells in vitro. E-cadherin, alpha-smooth muscle actin (SMA), Smad 2 and PPAR-gamma mRNA and protein expressions were detected by real-time PCR and Western blot, respectively. NRK52E treated with TGF-beta1 for 48 h induced EMT, as evidenced by loss of E-cadherin and de novo expression of alpha-SMA. EMT was almost completely blocked by evodiamine and rosiglitazone. TGF-beta1 significantly increased Smad 2 expression and decreased PPAR-gamma expression in NRK52E cells compared with the control group, while evodiamine and rosiglitazone almost reversed these effects. These observations suggest that evodiamine and rosiglitazone inhibit TGF-beta1-induced EMT in NRK52E cells. Smad 2 and PPAR-gamma signal pathway might participate in the effects of evodiamine and rosiglitazone in EMT induced by TGF-beta1.