Poster Presenter

Dioscorea Alata L. acts as a Novel Fibrosis Antagonizing Herb Partly by Down-Regulating TGF-beta/smad Signaling Pathway
Yu-Lin Yang, Shan-Yu Chang , Wen-Shan Lin, Tao-Chen Lee, Lea-Yea Chuang, Tung-Nan Liao, Min-Yuan Hung, Tsung-Jen Hung, Chien-Ya Hung
UAE

Background: Extracellular matrix (ECM) accumulation, which are characteristics of diabetic nephropathy (DN) are highly correlated with the up-regulations of transforming growth factor-beta (TGF-β). TGF-β is central to the development of renal fibrosis through stimulating the expression and inhibition of the catabolism of ECM proteins. In Asia, people use traditional Chinese medicine to enhance renal function. Among these herbs, Dioscorea, an agricultural plant, has been widely applied as an ingredient in Chinese medicine for promoting blood circulation. However, little is known about the anti-fibrosis effects and underlying mechanism of Dioscorea.

Method: Dioscorea alata was characterized and extracted using water. Renal cellular fibrosis was established in vitro using NRK-49F, a normal rat kidney interstitial fibroblast, treated with beta-hydroxybutyrate (β-HB). The fibrosis-regulating roles of Dioscorea alata was investigated in NRK-49F cells. Western blotting was used to examine the protein expression in TGF-β-related signal proteins such as type I and type II TGF-β receptor, Smads2/3, pSmad2/3, Smads4, and Smads7. ELISA was used to analyze bioactive fibronectin levels in the culture media. RESULTS: Dioscorea alata extract (DAE) significantly inhibited β-HB-induced fibrosis in NRK cells concomitantly with dose-dependent inhibition of the type I TGF-β1 receptors and its down-stream signals (e.q. Smad2/3, pSmad2/3, Smad4). Moreover, DAE dose-dependently enhanced inhibitory Smad7.

Conclusion: We suggest that Dioscorea alata acts as a novel fibrosis antagonizing herb partly by down-regulating TGF-β/smad signaling pathway.