IkappaBzeta Controls IL-17-triggered Gene Expression Program in Intestinal Epithelial Cells that Prevents Expansion of SFB and Attenuates Autoimmune Disorders [ilea]

Control of gut microbes is crucial for not only local defense in the intestine but also proper systemic immune responses. Although intestinal epithelial cells (IECs) play important roles in cytokine-mediated control of enterobacteria, the underlying mechanisms are not fully understood. Here we show that deletion of IkappaBzeta in IECs in mice leads to dysbiosis with marked expansion of segmented filamentous bacteria (SFB), thereby enhancing Th17 cell development and exacerbating autoimmune inflammatory diseases. Mechanistically, the IkappaBzeta deficiency results in Paneth cell loss and impaired expression of IL-17-inducible genes involved in IgA production. The Paneth cell loss is caused by aberrant activation of IFN-gamma signaling and a failure of IL-17-mediated recovery from IFN-gamma-induced damage. Thus, the IL-17R–IkappaBzeta axis in IECs contributes to the maintenance of intestinal homeostasis by serving as a key component in a regulatory loop consisting of the gut microbiota and immune cells Total RNA was extracted from the ilea of two pairs of Nfkbizfl/flVil1-Cre and co-housed gender-matched littermate controls (Nfkbizfl/fl), and the gene expression profiles were analyzed by microarray analysis.