P055 Exosomal miR-103a-3p from Crohn’s creeping fat-derived ASCs contributes to intestinal fibrosis by targeting TGFBR3 and activating fibroblasts

Abstract Background Mesenteric adipose tissue hypertrophy is a hallmark of Crohn’s disease (CD), and creeping fat (CF) is unique to CD. Adipose-derived stem cells (ASCs) from inflammatory status exhibited altered biological functions. The role of ASCs isolated from CF in intestinal fibrosis and the potential mechanism remains unclear. Methods ASCs were isolated from CF (CF-ASCs) and disease unaffected mesenteric adipose tissue (Ctrl-ASCs) of patients with CD. A series of in vitro and in vivo experiments were conducted to study the effects of exosomes from CF-ASCs (CF-Exos) on intestinal fibrosis and fibroblast activation. A miRNA microarray analysis was performed. Western blot, luciferase assay, and immunofluorescence were performed to further detect the underlying mechanisms. Results Our results indicated that CF-Exos promoted intestinal fibrosis by activating fibroblasts in a dose-dependent manner. They continuously promoted progression of intestinal fibrosis even after dextran sulfate sodium withdrawal. Further analysis showed that exosomal miR-103a-3p was enriched in CF-Exos and participated in exosome-mediated fibroblast activation. TGFBR3 was identified as a target gene of miR-103a-3p. Mechanistically, CF-ASCs released exosomal miR-103a-3p and promoted fibroblast activation by targeting TGFBR3 and promoting Smad2/3 phosphorylation. We also found that the expression of miR-103a-3p in diseased intestine was positively associated with degree of CF and fibrosis score. Conclusion Our findings showed that exosomal miR-103a-3p from CF-ASCs promotes intestinal fibrosis by activating fibroblasts via TGFBR3 targeting, suggesting that CF-ASCs are potential therapeutic targets for intestinal fibrosis in CD.