Fig. 4

circZNF609 inhibits pulmonary fibrosis progress via miR-145-5p/KLF4 axis. A After being transfected with pEX-circZNF609 or pEX-NC, MRC-5 cells were administrated 5 ng/ml TGF-β1 for 48 h. The miR-145-5p level was testified via qRT-PCR analysis; U6 was used as the internal reference. B The interaction between miR-145-5p and circZNF609 was verified by RNA pulldown assay. C Transfection of miR-145-5p inhibitors significantly decreased miR-145-5p expression in MRC-5 cells treated with 5 ng/ml TGF-β1 for 48 h. D Western blotting showed fibronectin, collagen I, vimentin, KLF4, and α-SMA protein levels. The results of the experiment were repeated at least three times. E Immunofluorescence staining detected α-SMA (red) levels in different groups; DNA staining by DAPI (blue) represents nuclear; bars = 100 μm. F EdU staining and CCK8 assay G for the assessment of cell proliferation in MRC-5 cells, showing that the inhibition of miR-145-5p inhibited TGF-β1-induced cell viability and proliferation. H The interaction between miR-145-5p and KLF4 mRNA was verified by RNA pulldown assay. I After being co-transfected with pEX-circZNF609 and miR-145-5p inhibitors, MRC-5 cells were administrated 5 ng/ml TGF-β1 for 48 h. Western blotting showed fibronectin, collagen I, vimentin, KLF4, and α-SMA protein levels. All data were expressed as the means ± SD of at least 3 independent experiments, *p < 0.05 and **p < 0.01