Blocking TGF-β expression inhibits silica particle-induced epithelial-mesenchymal transition in human lung epithelial cells.

The main characteristic of silicosis is irreversible fibrosis. Certain studies have shown that epithelial-mesenchymal transition (EMT) regulated by transforming growth factor-β (TGF-β) is involved in fibrosis. Thus, we suggest that TGF-β regulated EMT may play an important role in silicosis. In this study, we determined the expression of TGF-β-Smad2/3, EMT- and ECM-related markers in lung epithelial cells treated with silica particle by RT-PCR, western-blot and ELISA. In order to explore the role of TGF-β, we used TGF-β inhibitor in the cell model. We found that the cells lost the expression of epithelial phenotypic markers and acquired increased expression of mesenchymal cells markers with ECM deposition after treatment with silica particle. Moreover, the changes of EMT-related event was restricted in response to TGF-β inhibitor. These findings suggest that EMT is essentially involved in the pathogenesis of fibrosis induced by silica particles and down-regulating the TGF-β expression can inhibit the process of EMT.