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MicroRNA‐497 functions as an inflammatory suppressor via targeting DDX3Y and modulating toll‐like receptor 4/NF‐κB in cigarette smoke extract‐stimulated human bronchial epithelial cells
Author(s) -
Jia Rong,
Zhao XiaoFei
Publication year - 2020
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.3137
Subject(s) - transfection , apoptosis , flow cytometry , cell growth , microbiology and biotechnology , microrna , chemistry , blot , receptor , cell , messenger rna , cell culture , cancer research , biology , gene , biochemistry , genetics
Background We aimed to investigate the biological effect of miR‐497 in cigarette smoke extract (CSE)‐damaged human bronchial epithelial (HBE) cells and the underlying molecular mechanism. Methods MiR‐497 mimic was transfected into HBE cells to up‐regulate miR‐497 expression. Cigarette smoke extract (CSE, 20 μg/mL) was utilized to treat HBE cells to form the injury model. Cell proliferation and apoptosis were detected by CCK8 and flow cytometry assays. DDX3Y mRNA expression was determined by a quantitative reverse transcriptase‐polymerase chain reaction. The interaction between miR‐497 and DDX3Y was verified by a luciferase reporter assay. Protein expression levels were tested by western blotting. Results CSE treatment decreased miR‐497 level in HBE cells. CSE exposure restrained cell proliferation, promoted cell apoptosis and enhanced the relative expression of TLR4 and p‐NF‐κB p65. DDX3Y was predicted as a target of miR‐497. The mRNA and protein expression of DDX3Y was negatively modulated by miR‐497 in CSE‐injured HBE cells. Up‐regulation of miR‐497 by miR‐497 mimic increased cell proliferation and reduced cell apoptosis in CSE‐treated HBE cells, which were rescued by DDX3Y high expression in CSE‐treated HBE cells. Consistently, Bcl‐2 protein level was heightened, whereas Bax and actived caspase‐3/9 protein levels were decreased by miR‐497 mimic in CSE‐stimulated HBE cells, which was reversed by DDX3Y over‐expression in CSE‐stimulated HBE cells. The relative expression of TLR4 and p‐NF‐κB p65 was decreased by miR‐497 mimic, whereas they were rescued by DDX3Y over‐expression in CSE‐damaged HBE cells. Conclusions The results of the present study demonstrate that up‐regulation of miR‐497 exhibits a protective effect on CSE‐damaged HBE cells, which might be achieved by targeting DDX3Y and regulating the TLR4/NF‐κB pathway.