TGF-β1与EGF对肺泡Ⅱ型上皮细胞表型及功能的影响

Effect of TGF-β1 and EGF on the Phenotypical Change and Function of Type Ⅱ Alveolar Epithelial Cells

目的:探讨TGF-β1与EGF对肺泡Ⅱ型上皮细胞(RLE-6TN)的影响。方法:将细胞分成对照(C)、TGF-β1(T)、EGF(E)及TGF-β1+EGF(TE)组。采用相差显微镜观察细胞形态,免疫荧光检测α-SMA表达,W.B检测上皮、间质细胞标记物、MMPs及信号蛋白的表达;流式细胞术检测凋亡情况。结果:T及TE组RLE-6TN发生EMT转变并见间质标记物及MT1-MMP、MMP2表达上调,E组Vimentin、MT1-MMP、MMP2及CD147表达上调;T与E组p-ERK、p-38MAPK及p-Akt表达上调,T组p-Smad2表达上调;T与E组均见凋亡,TE组凋亡加剧。结论:单用EGF不能诱导RLE-6TN发生EMT,合用TGF-β1无协同诱导EMT,却能协同诱导凋亡。TGF-β1诱导EMT时,主要通过EGFR信号通路诱导MMPs表达。

Objective： To investigate the effect of TGF- β 1 and EGF on type Ⅱ alveolar epithelial cells. Methods： RLE-6TN cell lines were cultured and treated with TGF- β1 and EGF, four groups of control （ C ）, TGF- β1 （T）, EGF （ E ） and TGF- β1 ＋EGF （ TE ） were divided according to different treatments. The morphological alterations were examined by phase-contrast microscope, the expression of α -SMA were examined by immune fluorescence method, the expression of markers of the epithelial cells, mesenchymal cells, MMPs and signal proteins were assayed by Western Blot. Flow cytometer was adopted to estimate the apoptosis of cells. Results： TGF-β 1 alone or the combination of TGF- β 1 and EGF could not only induce the epithelial-mesenchymal transition （EMT） process of the RLE-6TN cells, but also upregulate the expression of the mesenchymal markers including MT1-MMP, MMP2, and CD147. The expression of vimentin, MT1-MMP, MMP2 and CD147 were upregulated in E group. The expressions ofp-ERK, p-38MAPK and p-Akt were increased in T and E group, p-Smad2 expression was upregulated in T group. And the apoptosis were obsevered in T, E and TE group, TE group showed greater apoptosis compared with other 2 groups. Conclusions： EGF alone could not induce the EMT of RLE-6TN, the combination of TGF- β 1 and EGF has not shown apparent effect on the induction of EMT but apoptosis inducement. EMT of RLE-6TN induced by TGF- β1 was primarily through MMPs expression with EGFR signaling pathways involved.