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

结肠炎是一种炎症性肠病（IBD），其特征在于大肠或结肠的慢性炎症。仅在美国，这种疾病就影响超过100万人，每年花费超过10亿美元，具有复杂的病因学，迄今为止，患者的有效治疗选择很少。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I3 C）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，I3 C能够预防结肠炎相关的生态失调并增加结肠丁酸。具体而言，I3 C防止结肠炎相关的革兰氏阴性细菌（例如产酸拟杆菌）的增加，同时也增加了产生丁酸的罗斯拜瑞氏菌。发现IL-22在I3 C治疗后显著增加，并且这种细胞因子的中和阻止了I3 C降低疾病严重程度并改变肠道微生物组和代谢组。在目前的提议中，中心假设是I3 C通过激活AhR调节串扰免疫细胞和结肠上皮细胞（CEC）来介导其有益作用，并依赖于IL-22的产生来介导其在结肠炎期间的保护作用。本研究的目的如下：（1）。将使用AhR对免疫细胞（T细胞和先天淋巴3型细胞/ILC 3）或CEC（两者均表达AhR）的条件性KO研究I3 C介导的保护作用中AhR的依赖性。这些研究将确定I3 C介导的作用是否依赖于免疫细胞和/或CEC中的AhR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。将重点关注AhR在调节I3 C介导的IL-22调节中的作用，以鉴定IL-22和IL-22促进基因上的AhR特异性二恶英反应元件（DREs）。2.）此外，将进行研究以确定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），这可能在结肠炎期间由I3 C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.