Role and Regulation of the AhR-IL22 axis in I3C-mediated protection against colitis

结肠炎是一种以大肠或结肠慢性炎症为特征的炎症性肠病（IBD）。仅在美国，这种疾病就影响了100多万人，每年花费超过10亿美元，其病因复杂，迄今为止，对患者来说，很少有有效的治疗选择。在目前的研究中，我们证明了在tnbs诱导的结肠炎中，在许多十字花科蔬菜中发现的天然吲哚产物（吲哚-3-甲醇，或I3C）和芳烃受体（AhR）的配体可有效预防结肠炎症状。最值得注意的是，I3C能够预防结肠炎相关的生态失调，并增加结肠丁酸盐。具体来说，I3C可以防止与结肠炎相关的革兰氏阴性菌（如增酸拟杆菌）的增加，同时也可以增加丁酸盐产生的Roseburia。IL-22在I3C治疗后显著升高，该细胞因子的中和阻止了I3C降低疾病严重程度和改变肠道微生物组和代谢组。在目前的建议中，中心假设是I3C通过激活AhR调节串音免疫细胞和结肠上皮细胞（CECs）来介导其有益作用，并依赖IL-22的产生来介导其结肠炎期间的保护作用。本研究的目的如下：1)我们将利用AhR对免疫细胞（T细胞和先天淋巴样3型细胞/ILC3s）或CECs的条件KO来研究AhR在i3c介导的保护作用中的依赖性，两者都表达AhR。这些研究将确定i3c介导的作用是否依赖于免疫细胞和/或CECs中AhR的表达，以预防结肠炎和改变疾病相关的微生物生态失调和代谢组学特征。将重点研究AhR在i3c介导的IL-22调节中的作用，以鉴定AhR特异性二恶英反应元件（DREs）对IL-22和IL-22促进基因的影响。2)。此外，研究将确定IL-22产生的细胞来源，并研究影响IL-22的表观遗传修饰（microRNA/miRNA和DNA甲基化），这些修饰可能在结肠炎期间通过I3C治疗介导。

Colitis is an inflammatory bowel disorder (IBD) characterized by chronic inflammation of the large intestine or colon. This disease, affecting over 1 million people and costing over a billion dollars/year in the US alone, has a complex etiology and to date, there are few and effective treatment options to patients. In the current study, we demonstrate that in TNBS-induced colitis, a natural indole product found in numerous cruciferous vegetables (Indole-3-carbinol, or I3C) and ligand for the aryl hydrocarbon receptor (AhR) is effective at preventing symptoms of colitis. Most notably, I3C was able to prevent colitis-associated dysbiosis and increase colonic butyrate. Specifically, I3C prevented increases in colitis-associated gram-negative bacteria (e.g. Bacteroides acidifaciens), while also increasing butyrate producing Roseburia. IL-22 was found to be significantly increased after I3C treatment, and neutralization of this cytokine prevented I3C from reducing disease severity and altering the gut microbiome and metabolome. In the current proposal, the central hypothesis is I3C mediates its beneficial effects through regulation of cross talk immune cells and colonic epithelial cells (CECs) by activation of AhR and depends on IL-22 production to mediate its protective effects during colitis. The aims of this study will be as follows: 1.) Dependency of AhR in I3C-mediated protective effects will be investigated using conditional KO of AhR on immune cells (T cells and innate lymphoid type 3 cells/ILC3s) or CECs, both of which express AhR. These studies will determine if I3C-mediated effects are dependent on AhR expression in immune cells and/or CECs in preventing colitis and altering disease-associated microbial dysbiosis and the metabolomic profile,. Focus on the impact AhR plays in regulating I3C-mediated modulation of IL-22 will be performed to identify AhR-specific dioxin response elements (DREs) on IL-22 and IL-22 promoting genes. 2.) Additionally, studies will be conducted to determine the cell source of IL-22 production and investigate epigenetic modifications( microRNA/miRNA and DNA methlyation) affecting IL-22, which could be mediated by I3C treatment during colitis.