I3C-MEDIATED PROTECTION AGAINST COLITIS DEPENDENT ON AHR EXPRESSION ON VIL1-EXPRESSING COLONIC EPITHELIAL CELLS

Abstract Many current treatments for ulcerative colitis (UC) often causes side effects warranting safe therapeutic strategies to control the pathogenesis of colitis. Current study was aimed to ascertain the possible role of aryl hydrocarbon receptor (AhR) in vil1-expressing colonic epithelial cells (CECs) during I3C-mediated protection against colitis. We investigated how intestinal regulatory mediators were altered in the absence or presence of AhR in CECs during I3C treatment under colitis or colitis-like conditions. We generated conditional AhR knockout mice in vil1-expressing CECs using the cre-flox system and induced colitis using the dextran sodium sulfate (DSS) model. Results showed that the mice with AhR deficiency in CECs (AV mice) lost the protective effects of I3C treatment during colitis and had a higher disease score with increased inflammation in the colon compared to the controls. Also, after treatment with I3C during DSS-induced colitis, AV mice were not able to prevent colitis-associated gut microbial dysbiosis even though flow cytometry analysis revealed AV mice were still capable of increasing IL-22 production by ILC3s in the colon. IL-22-ILC3 immune cell response was not the only major mechanism involved in I3C-mediated protection against colitis and regulation of the gut microbiome. Transcriptome analysis of RNA isolated from enriched CECs of experimental mice showed significant altered expression of several microRNAs, mucins (muc3 and muc13), and tight junction proteins in AV mice compared to controls. PCR gene expression data and direct effects of I3C on CECs using colonic organoids validated these results. In summary, AhR expression in CECs play a critical role in I3C-mediated prevention of colitis.