Macrophage-derived microRNA-223 Promotes Intestinal Mucosal Barrier Dysfunction via Exosomal Pathways in Inflammatory Bowel Disease

Background & Aim: Exosomes are effective mediators of cell-to-cell interactions and carry many regulatory molecules, including miRNAs, that can play crucial roles in diverse fundamental biological processes. However, to date, no study has reported macrophage exosomal involvement in the development of inflammatory bowel disease (IBD). This study investigated the specific miRNAs in macrophage-derived exosomes in IBD and the potential molecular mechanism. Methods: Dextran sulfate sodium (DSS) was used to generate IBD mice. The supernatants of murine bone marrow-derived macrophages (BMDMs) with or without lipopolysaccharide (LPS) were collected for exome isolation and miRNA sequencing. Lentiviruses were used to modify miRNA expression and further investigate the role of macrophage-derived exosomal miRNAs. In vitro, both mouse and human organoids were applied to a Transwell system in co-culture with BMDMs as a cellular IBD-related challenge.Results: Here, we show that LPS-induced macrophages can release exosomes containing various miRNAs, aggravating IBD. We analyzed miRNA sequencing of macrophage-derived exosomes, and miR-223 was selected for further study. In vivo, exosomes with high miR-223 expression contributed to the exacerbation of intestinal barrier dysfunction, which was further verified in both mouse and human colon organoids. Furthermore, time-dependent analysis of the mRNAs of DSS-induced colitis mouse tissue combined with miR-223 target gene prediction was performed to select the candidate gene, and the barrier-related factor TMIGD1 was identified.Conclusion: Collectively, these data indicated that macrophage-derived exosomal miR-223 played a novel role in intestinal barrier dysfunction by inhibiting TMIGD1 in the progression of DSS-induced colitis.