Crohn’s & Colitis Congress™

Sessions Speakers Exhibitors Floor Plan Buzz

P104 - ROLE OF TL1A AND ITS RECEPTOR DR3 IN REGULATING INTESTINAL TH9 CELL DIFFERENTIATION IN CROHN’S DISEASE (CD)-LIKE ILEITIS (Room Poster Hall)

Background: Death receptor 3 (DR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, has been implicated in regulating T helper type 1 (TH)1, TH2 and TH17 responses as well as regulatory T cell and innate lymphoid cell functions during immune-mediated diseases. However, the role of TL1A/DR3 system in modulating the function of other lymphocyte subsets, such as TH9, in CD is not fully understood. In this work, we investigated whether TL1A/DR3 signaling regulates chronic intestinal inflammation by promoting intestinal TH9 cell differentiation. Methods: CD4+ cells were purified by MACS sorting from mesenteric lymph nodes (MLNs) of 20-wk old SAMP/YitFc (WT) and DR3×SAMP/YitFc (KO) mice. TH9 cell differentiation was carried out under specific polarizing conditions (rIL-4, rTGF-β and TL1A). TH subsets were analyzed by flow cytometry and cell supernatants by ELISA. Results: Genetic deletion of DR3 effectively reversed the inflammatory phenotype in WT mice. Flow cytometry analysis revealed that TH9 polarized MACS purified CD4+ cells from WT mice produced higher IL-9 level than those from KO mice (29.5%±11.3 vs 3.4%±1.3, n=2). Similarly, IL-9 concentration was increased in supernatants from WT mice compared to those from KO mice (5070±785.2 vs 1216.7±104 p=0.05 n=3). While absent in KO mice, TH9 polarized cells from WT mice were enriched in dysfunctional FoxP3+CD25+ cells producing IL-17A, IL-9 and TNF (24%±10 vs 1.1%±0.2 n=2), and in pro-inflammatory FoxP3-CD25+ cells producing IL-9 and TNF (75.7%±13.7 vs 3.8%±0.2 n=2). Conclusions: Upon Th9 polarizing conditions, MLN from WT mice became enriched in TH9 cells in contrast to those from KO mice. Additionally, the frequency of pro-inflammatory CD4+CD25+ cells producing IL-9, IL17A and TNF proteins was increased in MLN from WT compared to KO mice. Our data suggest that the activity of TL1A/DR3 system is mainly pro-inflammatory and that TL1A/DR3 pathway may promote TH9 differentiation and pathogenicity.