RORα is critical for mTORC1 activity in T cell-mediated colitis [16S rRNA-seq]

Inflammatory bowel disease (IBD) is multi-factorial chronic intestinal inflammation driven by pathogenic T cells. The mechanisms underlying colitis pathogenicity and anti-TNF therapy resistance are not fully understood. Here we demonstrate that RORα is highly expressed in active UC patients, particularly in those non-responsive to anti-TNF treatment. Rorα deficient CD4+ T cells could not induce severe gut inflammation in a T cell transfer colitis model. Mechanistically, RORα regulated T cell infiltration in colon by promoting T cell migration and inhibiting T cell apoptosis. Meanwhile, genome-wide occupancy and transcriptome analysis revealed that RORα promoted mTORC1 activation. mTORC1 signaling, also hyperactivated in active UC patients, was necessary for T cell-mediated colitis. 16S rRNA-seq of gut microbiota isolated from cecum of WT and Rorα KO mice.