Ergosterol peroxide from Cordyceps cicadae ameliorates TGF-β1-induced activation of kidney fibroblasts

Chronic kidney disease is a growing public health problem with an urgent need for new pharmacological agents. Ergosterol peroxide (EP) is the major sterol produced by Cordyceps cicadae Shing (C cicadae), a widely used traditional Chinese medicine. C cicadae has been used to treat many kinds of diseases and has a potential benefit on renoprotection. This study aimed to investigate the anti-fibrotic effects of EP as well as the underlying mechanisms. A normal rat kidney fibroblast cell line (NRK-49F) was stimulated to undergo fibroblast activation by transforming growth factor-beta 1 (TGF-beta 1) and EP treatment was applied to explore its potential anti-fibrotic effects. Cell proliferation was investigated using MTT analysis. Fibrosis-associated protein expression was analyzed using immunohistochemistry and/or Western blotting. EP treatment attenuated TGF-beta 1-induced renal fibroblast proliferation, expression of cytoskeleton protein and CTGF, as well as ECM production. Additionally, EP blocked TGF-beta 1-stimulated phosphorylation of ERK1/2, p38 and JNK pathway. Moreover, the TGF-beta 1-induced expression of fibronectin was attenuated by either inhibition of MAPKs or by EP treatment. In conclusion, our findings demonstrate that EP is able to suppress TGF-beta 1-induced fibroblasts activation in NRK-49F. This new information provides a line of theoretical evidence supporting the use of C cicadae in the intervention of kidney disease and suggests that EP has the potential to be developed as a therapeutic agent to prevent renal fibrosis. (C) 2013 Elsevier GmbH. All rights reserved.