The Effect of miR-200 and Their Targets ZEB1/2 on Epithelial-mesenchymal Transition(EMT) in Early Pulmonary Fibrosis Caused by Acute Lung Injury / 昆明医科大学学报

ABSTRACT

Objective To observe the expression profiles of miR-200b/c and their targets ZEB1/2 in early pulmonary fibrosis caused by acute lung injury induced by lipopolysaccharide in mice.Methods Early pulmonary fibrosis caused by acute lung injury is built via a lipopolysaccharide three-hit regimen.Mice were sacrificed at post-injective day 3,7,14,21 respectively and the lung tissue specimens were collected.The lung tissue sections were stained with HE and Masson staining and pathological changes were observed by optical microscope.The expression profiles of miR-200b,miR-200c,ZEB1 mRNA and ZEB2 mRNA were detected by real-time PCR.Western blot was utilized to detect the levels of ZEB1,ZEB2,E-cadherin,Vimentin,α-SMA proteins.Results (1) pathological findings:compared with the control group,the collagen fibers deposited on on the third day after LPS treatment and pulmonary fibrosis gradually worsened;(2) Real time-PCR results:With the aggravation of pulmonary fibrosis,miR-200b and miR-200c levels were declined and the levels of miR-200b/c at post-injective day 7,14,21 were significantly lower than that of control group (P＜0.01).ZEB1 mRNA and ZEB2 mRNA levels were gradually increased in the process of pulmonary fibrosis and the increased magnitude of ZEB2 mRNA was more significant than that of ZEB1 mRNA;(3) Western blot results:ZEB1 and ZEB2 protein levels were also gradually increased,consistent with their mRNA levels and the expression of E-cadherin protein was decreased while Vimentin and oα-SMA protein levels increased with the evolution of pulmonary fibrosis caused by acute lung injury.Conclusion miR-200b and miR-200c promote epithelial-mesenchymal transition by inhibiting their targets ZEB1/2 in early pulmonary fibrosis caused by acute lung injury induced by LPS.