MiR-340-5p mitigates the proliferation and activation of fibroblast in lung fibrosis by targeting TGF-β/p38/ATF1 signaling pathway.

Abstract

Idiopathic pulmonary fibrosis (IPF) is associated with the occurrence and progress of the proliferation and activation of lung fibroblast. Recent studies have shown that microRNA-340-5p (miR-340-5p), a member of miRNA family, has modulated the skin fibroblast proliferation in scar formation disease. However, it is elusive whether miR-340-5p exert a pulmonary anti-fibrotic effect on IPF by moderating fibroblast bioactivity. The present study aimed to investigate the role of Adam10 in lung fibroblast regulation. Human lung fibroblasts were carried out Transforming Growth factor-β (TGF-β) to stimulate proliferation and activation. MiR-340-5p mimics or inhibitor loaded in pcDNA3.1 aimed at overexpression or inhibition were respectively delivered to lung fibroblast using Lipofectamine 2000 for transfection. Then, siRNA-ATF1 (Activating transcription factor 1) was utilized to knockdown ATF1 expression in lung fibroblast after miR-340-5p overexpression and probed the role of ATF1 in lung fibroblast. Western blotting, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Dual-Luciferase reporter system, Cell Counting Kit-8 (CCK-8) assay, scratch assay, and immunofluorescence were conducted to measure the alteration of miR-340-5p, ATF1, and fibrosis-relative level. We find that the expression of miR-340-5p markedly increases or decreases in fibroblast after mimics or inhibitor transfection respectively. Moreover, we demonstrate that the overexpression of miR-340-5p reduces the expression of ATF1 to prevent fibroblast activation and proliferation by targeting ATF1 and restrain MAPK/p38 pathway following TGF-β stimuli. The above proved that the increased miR-340-5p ameliorates the activation and proliferation of lung fibroblast in fibrosis process via targeting ATF1 and MAPK/p38 pathway. Our research provides novel insight on the miRNA modulation of process of TGF-β stimuli in lung fibroblast and verifies a potential target for the therapy of lung fibrosis in the future.