P174 Treg Cell and Human Intestinal Myofibroblast-Derived Amphiregulin induced by TGF-β Promotes Colitis-Associated Intestinal Fibrosis

Abstract

Abstract Background Intestinal fibrosis is one of the most threatening complications of Crohn’s disease (CD). Intestinal fibrosis is usually the result of chronic inflammation, and T cell response is the main driver of intestinal inflammation. At present, there are few researches on the mechanism of Treg cells in intestinal fibrosis, and the role of Treg-derived Areg in intestinal fibrosis has not been studied. Methods AREG and TGF-β expression was assessed in patients with CD with or without intestinal fibrosis by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). In this study, dextran sulfate sodium (DSS)-induced chronic colitis model in wild-type (WT) and Areg-/- mice and T-cell transfer model with WT and Areg-/- Treg cells were used. CD4+ T cell expression of AREG induced by Treg cell differentiation-related cytokines and self-secreted cytokines was determined by Western blotting. Human intestinal myofibroblasts expression of AREG induced by different cytokines was determined by qRT-PCR. The effect of AREG on proliferation/migration in human intestinal myofibroblasts was determined. Results AREG and TGF-β expression was increased in fibrotic sites compared with nonfibrotic sites from patients with CD. Although DSS-induced more severe colitis in Areg-/- mice, which developed less severe intestinal fibrosis compared with WT mice on DSS insults. Transfer of Areg-/- Treg cells induced less severe fibrosis in Rag-/- mice compared with WT Treg cells. TGF-β promoted AREG expression in Treg cells by activating Smad3. In addition, TGF-β promoted the AREG expression in Treg cells in a time and dose dependent manner. TGF-β also promoted the AREG expression in human intestinal myofibroblastss from CD patients with fibrosis. AREG promoted human intestinal myofibroblast proliferation and motility. Conclusion These findings revealed that Treg and human intestinal myofibroblast-derived AREG induced by TGF-β promotes intestinal fibrotic responses in experimental colitis and human patients with CD.