miR‐223 improves intestinal inflammation through inhibiting the IL‐6/STAT3 signaling pathway in dextran sodium sulfate‐induced experimental colitis.

Introduction: The pathogenesis of inflammatory bowel disease (IBD) has not yet been clarified and is closely related to several pro‐inflammatory factors. MicroRNA‐233 (miR‐223) might be involved in the development of IBD; however, the mechanism underlying its pathogenesis is unclear. In this study, we attempted to determine the role of miR‐223 in dextran sodium sulfate (DSS)‐induced colitis and explore the involvement of the IL‐6/STAT3 pathway in the development of intestinal mucosal inflammation. Materials and Methods: Except control (WT) group, male C57BL/6 mice were provided DSS, then treated for with miR‐223 agomir or antagomir including DSS group, DSS + miR‐223 agomir (DSS + A) group, and DSS + miR‐223 antagomir (DSS + AN) group. The colitis symptoms were observed, the disease activity index (DAI) score were recorded daily, and colonic inflammation was evaluated by histopathological scoring. The expression of myeloperoxidase (MPO), cytokines and IL‐6/STAT3 pathway‐related proteins were measured. Results: miR‐223 expression in the terminal ileum and colon was increased in the DSS group compared with the WT group. Colitis symptoms were significantly alleviated in the DSS + A group and exacerbated in the DSS + AN group after administration of the miR‐223 agomir and antagomir, respectively. MPO, tumor necrosis factor‐α, IL‐6, and IL‐17 were decreased and IL‐10 was increased in the DSS + A group, but these changes were reversed in the DSS + AN group. Gp130, p‐STAT3, Bcl‐2, and Bcl‐xl in the colon declined in the DSS + A group, but these levels increased in the DSS + AN group. Conclusions: The upregulation of miR‐223 by agomir administration alleviated colonic inflammation in a DSS‐induced colitis model, which was likely mediated by inhibiting the production of pro‐inflammatory cytokines via the IL‐6/STAT3 signaling pathway. These findings provide evidence that miR‐223 might have potential therapeutic implications in IBD. [ABSTRACT FROM AUTHOR]