miR-21 attenuates TGF-β-induced epithelial-mesenchymal transition in mouse alveolar type II cells. The relative expression of mRNA of lung epithelial cell marker genes (E-cadherin and SFTPC) or EMT marker genes (vimentin, α-SMA, Zeb1 and Zeb2) prior to culture or 6 days after culture in the condition inducing EMT is shown. The values are mean ± SEM (n = 6). mRNA is expressed relative to levels observed prior to culture. NC: cells not cultured. MOCK: cells only treated with transfection reagents. Con siRNA: cells transfected with non-targeting siRNA. miR-200c: cells transfected with synthesized miR-200c. miR-21-i: cells transfected with miR-21 inhibitor. miR-200c & miR-21-i: cells co-transfected with both synthesized miR-200c and miR-21-i. The data were analyzed by one-way analysis of variance with a post hoc test (Scheffé’s test). * p < 0.05 versus NC. † p < 0.05 versus MOCK. § p < 0.05 versus Con siRNA.