BACKGROUND: Whereas intestinal epithelial barrier dysfunction is implicated in inflammatory bowel disease (IBD), the underlying mechanisms remain elusive. Tumor necrosis factor alpha stimulated gene 6 (TSG-6) is a secretory protein with anti-inflammatory properties. Our previous research demonstrated TSG-6 can relieve intestinal inflammation and mucosal damage. However, the underlying mechanism and targets remain unclear. This research sought to explore how TSG-6 regulates the intestinal epithelial barrier and its mechanistic role in experimental colitis. METHODS: IBD mouse model was generated using dextran sodium sulfate (DSS), with or without intraperitoneal injection of TSG-6(100 microg/kg or 200 microg/kg). The effects of TSG-6 on colonic inflammation and intestinal barrier function were investigated. Label-free quantitative proteomic analysis was performed on intestinal samples to explore the mechanism and therapeutic target of TSG-6. Molecular interactions were determined by co-immunoprecipitation (Co-IP) and immunofluorescence colocalization. RESULTS: TSG-6 treatment significantly attenuated DSS-induced colitis symptoms and inflammatory cell infiltration. Microarray analysis revealed that TSG-6 decreased pro-inflammatory cytokine levels in colon tissue. TSG-6 restored the intestinal epithelial barrier through the promotion of intestinal epithelial cells (IECs) proliferation and mitigation of tight junctions (TJs) damage. Mechanistically, TSG-6 promoted tuft cells differentiation and increased interleukin-25 (IL-25) levels by directly binding to Pou class 2 homeobox 3(Pou2f3) and up-regulating its expression in the gut. CONCLUSIONS: This study demonstrated TSG-6 as a positive regulator of tuft cells differentiation by interacting with Pou2f3, and the effectiveness of exogenous TSG-6 treatment on maintaining intestinal barrier integrity showed a promising potential for its clinical application.