miR-937 serves as an inflammatory inhibitor in cigarette smoke extract-induced human bronchial epithelial cells by targeting IL1B and regulating TNF-α/IL-17 signaling pathway

Abstract

INTRODUCTION This study aimed to elucidate the biological implication of miR-937 in cigarette smoke extract (CSE)-induced human bronchial epithelial (HBE) cells and to further investigate its possible regulatory mechanism. METHODS Public datasets were downloaded to identify differentially expressed genes and subjected to Kyoto encyclopedia of genes and genomes ( KEGG) pathway enrichment analysis in chronic obstructive pulmonary disease (COPD). Online prediction site and luciferase reporter assay were applied to determine the target correlation between miR-937 and IL1B. RT-qPCR, Western blot and Enzyme-Linked Immunosorbent Assays (ELISA) analyses were used to evaluate the expressions of indicated molecules. HBE cells were exposed with CSE (20 mu g/mL) to construct the in vitro COPD model. Cell proliferation and apoptosis were measured through cell counting kit 8 and Annexin-V/propidium iodide (PI) staining assays. RESULTS IL1B was found to be up-regulated in COPD samples compared with healthy controls and had a high correlation with the TNF and IL-17 pathways according to the data from GSE57148. Moreover, IL1B was predicted to be a target of miR-937, and it was negatively regulated by miR-937. CSE treatment reduced the miR937 expression, meanwhile decreased the HBE cells proliferation, enhanced cells apoptosis, and elevated the expression of IL-6, IL-17, and TNF-alpha. Moreover, in the CSE model, upregulation of miR-937 promoted cells viability, restrained cells apoptosis, and decreased levels of IL-6, IL-17, and TNF-alpha were noted, which could be abolished by overexpression IL1B. In contrast, inhibiting miR-937 impeded cells proliferation, promoted cells apoptosis and elevated levels of IL-6, IL-17 and TNF-alpha, which could be rescued by IL1B-knockdown in CSE-induced HBEs. CONCLUSIONS These findings suggest that miR- 937 plays a protective role on the HBEs after CSE damage, which may be achieved via targeting IL1B and inhibiting the TNF-alpha/IL-17 signaling pathway.