Role of the environmental sensor, AhR on colitis

环境传感器 AhR 对结肠炎的作用

基本信息

批准号：
10390988
负责人：
Mitzi Nagarkatti
金额：
$ 49.99万
依托单位：
UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-27 至 2026-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10390988
关键词：
3-Dimensional ARNT gene ATAC-seq Affect Anti-Inflammatory Agents Antiinflammatory Effect Aryl Hydrocarbon Receptor Attenuated Binding Biological Assay Broccoli - dietary CD4 Positive T Lymphocytes Cabbage - dietary Cauliflower Cells Chromatin Chronic Clinical Colitis Colon Complex Crohn&apos s disease DNA DNA Methylation Data Defensins Dietary Factors Dietary Indole Dietary Phytochemical Dioxins Disease model Electrophoretic Mobility Shift Assay Elements Environmental Pollutants Environmental Risk Factor Epigenetic Process Epithelial Epithelial Cells FOXP3 gene Gastrointestinal tract structure Gene Expression Genes Genetic Histone Acetylation Histone Deacetylase Histone Deacetylase Inhibitor Histone Deacetylation Human Immune response Immune system Immunomodulators Immunosuppression Indole-3-Carbinol Inflammation Inflammatory Bowel Diseases Interleukin-17 Intestines Knockout Mice Ligands Ligation Mediating MicroRNAs Modeling Mus Pathogenesis Pathway interactions Patients Peptides Plants Play Prevention Property Protein Family Quantitative Reverse Transcriptase PCR Receptor Activation Regulation Regulatory T-Lymphocyte Reporter Resistance Response Elements Role Surface T cell differentiation T-Lymphocyte Testing Tissues Ulcerative Colitis antimicrobial peptide aryl hydrocarbon receptor ligand base beta-Defensins chromatin remodeling dextran sulfate sodium induced colitis epigenetic regulation gut dysbiosis gut microbiota histone modification intestinal barrier intestinal epithelium microbial microbial colonization microbial host microbiota novel pollutant prevent promoter sensor transcription factor villin

项目摘要

The environmental sensor, aryl hydrocarbon receptor (AhR) serves as a ligand for pollutants as well as for plant, microbial and endogenous compounds. Following AhR ligation, the activated AhR regulates gene expression through the binding of AhR/ARNT complex to specific DNA motifs known as Dioxin Response Elements (DREs). Studies from our lab and elsewhere have shown that some AhR ligands have potent immunosuppressive properties. Inflammatory bowel disease (IBD) results from chronic inflammation in the gastrointestinal tract that affects 1.5 million people in the US. The pathogenesis of IBD involves complex interactions between gut microbiota, immune response, environmental and dietary factors, and genetic/epigenetic regulation. Recently, we made an exciting observation that the AhR ligand and plant product, I3C ameliorates colitis in mice, which was associated with anti-inflammatory effects, regulation of gut dysbiosis, and enhanced expression of β-defensins (mBD1,2,3) by Colonic Epithelial Cells (CEC). β-defensins constitute antimicrobial peptides (AMPs) that resist microbial colonization of epithelial surfaces in the colonic tissue. β- defensins may also mediate anti-inflammatory effects. In fact, studies have shown defective expression of intestinal AMPs particularly defensins in IBD patients. We were excited to uncover DREs in the promoters of mouse β-defensins (mBD1, 2, and 3). In the current study, we will test the central hypothesis that dietary indoles (I3C) attenuate colitis through AhR activation leading to increased expression of mBDs by CECs via pathways involving DREs, and/or epigenetic regulation resulting in modulation of microbiota and prevention of epithelial barrier damage. Furthermore, we propose that mBDs induced by I3C play a critical role in restoring healthy gut microbiota, preventing intestinal barrier damage and suppressing colonic inflammation through induction of Tregs. Aim 1 will test the mechanisms of mBD induction by dietary indoles. We will use reporter assay, promoter bashing and electrophoretic mobility shift assay to determine whether I3C activated AhR directly binds to the DREs to induce mBDs. We will also determine the effect of I3C on the mBD expression by using AhR cKO mice with AhR deletion in IEC, ILC3 and Tregs. In Aim 2, we will study epigenetic regulation of β-defensins by dietary indoles. To that end, we will test whether I3C regulates mBD expression by altering histone modification and decreasing DNA methylation. We will specifically determine if I3C regulates the SATB1-mediated histone deacetylation and chromatin remodeling. In Aim 3, we will test whether administration of mBDs offers protection from colitis by regulating gut dysbiosis, preventing CEC barrier damage, enhancing Treg subsets and decreasing Th17 subpopulations to attenuate colonic inflammation. Finally, we will use mBD KO mice to test whether mBDs are required for I3C-mediated protection from colitis. The proposed studies are highly significant because they will identify novel mechanisms through which dietary indoles suppress colitis by altering the microbiota, through activation of AhR leading to increased expression of host-derived AMPs, specifically β-defensins.

环境传感器芳基烃受体（AHR）用作污染物的配体对于植物，微生物和内源性化合物。 AHR连接后，激活的AHR调节基因通过AHR/ARNT复合物与特定DNA基序的结合表达称为二恶英反应元素（DRES）。我们实验室和其他地方的研究表明，某些AHR配体具有有效免疫抑制特性。炎症性肠病（IBD）是由慢性炎症导致的胃肠道影响美国150万人。 IBD的发病机理涉及复杂肠道菌群，免疫响应，环境和饮食因素以及遗传/表观遗传调节。最近，我们对AHR配体和植物产品的令人兴奋的观察， I3C可以改善小鼠的结肠炎，这与抗炎作用有关，肠道营养不良的调节，并增强了结肠上皮细胞（CEC）的β-防御素（MBD1,2,3）的表达。 β-防御素构成抗菌胡椒（AMP），可抵抗结肠组织中上皮表面的微生物定植。 β- 防御素也可能介导抗炎作用。实际上，研究表明 IBD患者中的肠放大器尤其是防御素。我们很兴奋地发现在小鼠β-防御素（MBD1、2和3）。在当前的研究中，我们将检验饮食吲哚的中心假设（I3C）通过AHR激活减轻结肠炎，从而导致CEC通过途径增加MBD的表达涉及DRES和/或表观遗传调节，导致微生物群调节和预防上皮屏障损坏。此外，我们建议由I3C诱导的MBD在恢复健康的肠道中起关键作用微生物群，防止肠道屏障损伤并通过诱导来抑制结肠注射 Tregs。 AIM 1将通过饮食吲哚测试MBD诱导的机制。我们将使用记者分析，发起人爆炸和电泳迁移率转移测定法，以确定I3C激活的AHR是否直接与诱导MBD。我们还将使用AHR CKO小鼠确定I3C对MBD表达的影响 IEC，ILC3和Tregs中的AHR删除。在AIM 2中，我们将通过饮食研究β-防御素的表观遗传调节吲哚。为此，我们将通过更改组蛋白修饰和减少DNA甲基化。我们将明确确定I3C是否调节SATB1介导的组蛋白脱乙酰化和染色质重塑。在AIM 3中，我们将测试MBD的管理是否提供保护通过调节肠道营养不良，防止CEC屏障损伤，增强Treg子集并减少。 Th17亚群减弱结肠炎症。最后，我们将使用MBD KO小鼠测试MBD I3C介导的防肠癌的保护需要。拟议的研究非常重要，因为它们将确定饮食中的吲哚的新型机制，通过改变微生物群来抑制结肠炎 AHR的激活导致宿主衍生AMP的表达增加，特别是β-防御素。