丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路是细胞外信号刺激引起细胞核反应的共同通路,是介导上皮间质转型(epithelial-mesenchymal transition,EMT)的细胞内信号分子。许多信号分子都可以通过MAPK信号通路介导EMT的发生。进一步研究探索MAPK信号通路与EMT之间的分子机制,将有助于更好地理解EMT与疾病的发展机制,从而为疾病的治疗提供新的思路和方法。
Epithelial-mesenchymal transition （EMT） plays an important role in fibrotic diseases. We have previously showed that silica induces EMT in human bronchial epithelial cells （BECs）; however, the underlying mechanism of silica-induced EMT is poorly understood. In the present study, we investigated the role of Snail in silica-induced EMT in human BECs in vitro. Human BECs were treated with silica at various concentrations and incubation times. Then MTr assay, western blot, electrophoretic mobility shift assay （EMSA）, and small interfering RNA （siRNA） transfection were performed. We found that silica increased the expression and DNA binding activity of Snail in human BECs. SNAI silica-induced expression siRNA upregulated the siRNA inhibited the of Snail. Moreover, SNAI expression of epithelial marker E-cadherin, but attenuated the expression of mesenchymal marker a-smooth muscle actin and vimentin in silica-stimulated cells. These results suggest that Snail mediates the silica-induced EMT in human BECs.
Objective To investigate the roles of Rho/Rock signaling pathway in silica-induced Epithelial-mesenchymal transition （EMT） in human bronchial epithelial cells （BEC） in vitro. Methods Human BEC were incubated with silica with various concentrations for indicated times. Cell viability was assayed by MTT test. Morphologic Changes were observed by microscope. Mesenchymal marker a-smooth muscle actin （a-SMA）, vimentin （Vim）, and epithelial marker E-cadherin （E-cad） were analyzed by Western Blot. The pull-down assay was used to measure Rho activity. In the prevention experiments, the specific inhibitor for Rho effector ROCK （Y27632） was used to inhibit the activity of Rho. Results Human BEC stimulated with silica were converted from a ＂cobblestone＂ epithelial structure into an elongated fibroblast-like shape structure. Incubation of human BEC with silica induced de novo expression of a-SMA and Vim, and loss of E-cad. Also, silica treatment resulted in Rho activation in human BEC. Y27632 up-regulated the E-cad expression but attenuated a-SMA and Vim expression in silica-stimulated cells. Conclusion The activation of Rho/ROCK signaling pathways is most likely involved in Silica-induced EMT in human bronchial epithelial cells.
HU Yong BinLI XiangLIANG Guan NanDENG Zheng HaoJIANG Hai YingZHOU Jian Hua
