空气细颗粒物暴露减弱支气管上皮细胞上皮表型的研究OA

OBJECTIVE To investigate the effects of ambient fine particulate matter(PM2.5)on epithelial-mesenchymal transition(EMT)-related molecules in human bronchial epithelial cells and to define the time-and concentration-dependent pattern of these effects.METHODS Beas-2b cells were exposed to PM2.5 at 0,25,50,100 μg/ml and collected at 24,48,and 72 h.Quantitative real-time PCR(qRT-PCR)was performed to detect the mRNA levels of E-cadherin,Vimentin,Snail2,ZEB1,ZEB2,and MMP-9.Western-blotting was used to detect the protein levels of E-cadherin and Vimentin.RESULTS Compared with the control group,PM2.5 significantly downregulated E-cadherin mRNA in Beas-2b cells,with a significant main effect of concentration(P<0.000 1),whereas Vimentin mRNA levels showed no significant change.At the protein level,E-cadherin was significantly decreased after 24 h of PM2.5 exposure in the 50 and 100 μg/ml groups compared with controls,while Vimentin protein expression remained unchanged,consistent with the transcriptional findings.For Snail2 mRNA,a significant interaction between PM2.5 concentration and exposure time was observed[F(6,24)=7.582,P=0.000 1].Simple effects analysis showed that after 24 h of PM2.5 exposure,Snail2 mRNA was significantly increased only in the 100 μg/ml PM2.5-treated group,whereas after 48 and 72 h of PM2.5 exposure,significant increases were observed in all PM2.5-treated groups(25,50,and 100 μg/ml).No significant interaction between concentration and exposure time was found for MMP-9 mRNA;however,both the main effect of concentration[F(3,24)=16.08,P<0.000 1]and the main effect of exposure time[F(2,24)=6.979,P=0.004 1]were significant.Compared with the control group,the overall MMP-9 mRNA was significantly increased in all PM2.5-treated groups(25,50,and 100 μg/ml),and the overall MMP-9 mRNA level at 72 h of PM2.5 exposure was higher than those at 24 and 48 h.No significant changes were observed in ZEB1 and ZEB2 mRNA levels.CONCLUSION PM2.5 exposure attenuates the epithelial phenotype of human bronchial epithelial cells,and the effect may be mediated,at least in part,by the upregulation of Snail2 and MMP-9.