TL1A signaling enhances the differentiation of TH9 cells and TH9-driven mucosal pathologies via BATF and BATF3 signaling pathways

The TNF family member TL1A (TNFSF15) co-stimulates several T helper subsets and promotes T cell-dependent models of inflammatory diseases, including inflammatory bowel diseases (IBD) and allergic lung disease. TL1A polymorphisms confer susceptibility to IBD and have been associated with disease severity. In this study, we identified TL1A as a strong inducer of TH9 cell differentiation in vitro. Mechanistically, TL1A induced NF-B signaling and down-stream STAT6 activation and facilitated cooperative binding of BATF, BATF3, and IRF4 to the Il9 promoter. In vivo, utilizing an adoptive T cell transfer model we demonstrated that TL1A promoted IL-9-dependent, TH9 cell-induced intestinal and lung inflammation and blocking anti-IL-9 antibodies attenuated TL1A-driven mucosal inflammation. Our results demonstrate that TL1A promotes TH9 cell differentiation and function and define a role for IL-9 in TL1A-induced mucosal inflammation. 4 samples (2x2)