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

Y.-Q. Wei, Y.-F. Guo, S.-M. Yang, H.-H. Ma, J. Li

Department of Pulmonary and Critical Care Medicine, Shaanxi Provincial People’s Hospital, Xian, China. llz_spph@163.com

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• Respiratory Medicine

OBJECTIVE: 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.

MATERIALS AND METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.

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