Abstract
Inflammatory bowel diseases (IBDs) are chronic immune disorders that occur in the intestinal tract. Previous studies have revealed that intestinal epithelial cells (IECs) play critical roles in the development of IBDs, and therapies targeting IECs hold great potential for the treatment of IBDs. However, the roles of microRNAs (miRs) in the regulation of IEC properties and whether they can be used as targets for IEC regulation and IBD treatment are largely unknown. The aim of the present study was to investigate the role of the miR-452-5p/Mcl-1 axis in the regulation of the properties of IECs during the pathology of IBD. A dextran sulfate sodium-induced mouse model of ulcerative colitis (UC) and an in vitro lipopolysaccharide-stimulated IEC-6 cell model were investigated. The results revealed that miR-452-5p expression in the IECs of the mice increased significantly upon UC induction, and the knockdown of miR-452-5p alleviated the IBD symptoms. Furthermore, the suppression of miR-452-5p downregulated the expression of the inflammatory cytokines IL-6, IL-8 and TNFα, and upregulated the expression of intestinal barrier-associated molecules, namely occludin, zona occludens 1 and mucin-2 in IECs in vitro and in vivo. Notably, the results indicated that miR-452-5p modulated the responses of IECs by negatively regulating the expression of Mcl-1, as the knockdown of Mcl-1 abrogated the effects of miR-452-5p suppression on IECs. The present study suggested that miR-452-5p regulated the responsiveness of IECs to influence the development of UC in an Mcl-1-dependent manner. These observations provide important information to improve the understanding of IBD pathogenesis and indicate that targeting the miR-452-5p-Mcl-1 signaling axis in IECs holds potential for IBD treatment.