Vitamin D Receptor Regulation of Microbiota in Intestinal Epithelia

维生素 D 受体对肠上皮微生物群的调节

基本信息

批准号：
9197981
负责人：
Jun Sun
金额：
$ 35.98万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-01 至 2020-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9197981
关键词：
Affect Animal Model Apoptosis Area Autophagocytosis Biology Cell Culture Techniques Cell physiology Cells Chemical Injury Chronic Chronic Disease Colitis Data Down-Regulation Ecology Elements Ensure Environmental Risk Factor Epithelial Epithelial Cells Equilibrium Excision Experimental Models Gene Targeting Genetic Predisposition to Disease Germ-Free Goals Homeostasis Housing Human Immune Impairment In Vitro Inflammation Inflammatory Bowel Diseases Integration Host Factors Interleukin-10 Intestinal Diseases Intestines Knock-out Knowledge Link Messenger RNA Microbe Modeling Molecular Mucositis Mus Natural Immunity Organoids Paneth Cells Paper Pathogenesis Pathway interactions Patients Peptides Play Population Proteins Regulation Reporting Research Research Personnel Risk Role Severities Sodium Dextran Sulfate Stem cells System Testing Transgenic Mice Vitamin D Vitamin D3 Receptor antimicrobial base crypt cell design disorder risk fecal transplantation functional restoration gut microbiome gut microbiota innovation insight intestinal epithelium intestinal homeostasis microbial microbiome microbiota mouse model novel novel strategies overexpression prevent public health relevance receptor receptor expression receptor function risk variant salmonella colitis

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of our study is to elucidate the molecular basis for host factors involved in maintaining microbial homeostasis and to develop novel approaches that prevent and treat inflammatory bowel diseases (IBD) by restoring host-microbe relationships. Reduced levels of vitamin D and its receptor VDR have been found in human IBD and experimental colitis. In colitis animal models, downregulation of VDR promotes the severity, extent, and duration of mucosal inflammation. We have shown that conditional removal of VDR in the intestinal epithelium made mice more susceptible to chemical injury and Salmonella-colitis. Our recent Gut paper has demonstrated that intestinal epithelial VDR conditional knockout (VDRΔIEC) leads to dysbiosis. However, how intestinal epithelial VDR is involved in maintaining microbial homeostasis and innate immunity remains largely unknown. The objective of this application is to study special consequences of VDR deficiency in Paneth cells and dysbiosis in the inflamed states. We study Paneth cells because: 1) the Paneth cells sense microbes and secrete anti-microbial peptides (AMPs); 2) the roles of Paneth cells are dependent on a functional autophagy pathway, which is essential in innate immunity and microbial ecology; and 3) a lack of ATG16L1, an IBD risk genes, leads to abnormal Paneth cells in the intestine. Intriguingly, we are the first to report that ATG16L1 is a target gene of VDR. Th absence of intestinal epithelial VDR is accompanied by a reduction in the mRNA and protein levels of ATG16L1. Therefore, we hypothesize that intestinal epithelial VDR is a determinant of IBD risk through its actions on Paneth cell functions and microbial assemblage in intestinal homeostasis. We have now developed novel experimental models to investigate VDR actions that critically affect host functions and microbiota of the intestine. Aim 1 will test the working hypothesis that intestinal epithelial VDR determines the function of Paneth cells and autophagy, thus changing gut microbiota in inflammation. We will A) elucidate how intestinal epithelial VDR leads to abnormal Paneth cells (impaired differentiation and decreased AMPs), in VDRΔIEC and VDRΔpaneth cell mice; B) determine effects and mechanisms of VDR on autophagy regulators through apoptosis/autophagy balance, using organoids and VDR transgenic mice; and C) investigate whether over-expression of intestinal VDR restores Paneth cells and autophagy, using organoids and Tg-I-VDR mice. Aim 2 will test the working hypothesis that regulating the microbiome and restoring balance in VDR functions and the microbiome will restore function of Paneth cells and autophagy, thus reducing severity of colitis. We will: A) investigate the role of intestinal epithelial VDR in altering bacterial populations when administered via fecal transplantation or recolonization in originally germ-free mice; and B) define the effect and mechanism of forced intestinal VDR expression in restoring microbial homeostasis though Paneth cell and autophagy regulation in IL10-/- colitis mice. Our studies are innovative because they provide a unifying hypothesis that can potentially account for defective autophagy, abnormal Paneth cells, and dysbiosis found in many patients with IBD and intestinal disorders. These insights will lead to novel strategies to prevent and treat IBD and intestinal disorders.

描述（由适用提供）：我们研究的长期目标是阐明涉及维持微生物稳态的宿主因素的分子基础，并通过恢复宿主 - 微生物关系来预防和治疗炎症性肠病（IBD）。在人IBD和实验性结肠炎中发现了维生素D及其受体VDR的水平降低。在结肠炎动物模型中，VDR的下调促进了粘膜感染的严重程度，程度和持续时间。我们已经表明，在肠上皮中有条件地去除VDR，使小鼠更容易受到化学损伤和沙门氏菌炎。我们最近的肠道论文表明，肠上皮VDR条件敲除（VDRΔIEC）导致营养不良。然而，肠上皮VDR如何参与维持微生物稳态和先天免疫力仍然很大程度上是未知的。该应用的目的是研究Paneth细胞中VDR缺乏的特殊后果和发炎状态的失调。我们研究了泛细胞，因为：1）泛池细胞感知微生物和秘密抗微生物辣椒（AMPS）； 2）Paneth细胞的作用取决于功能性自噬途径，该途径在先天免疫组织化学和微生物生态学中至关重要； 3）缺乏IBD风险基因ATG16L1会导致肠内异常的paneth细胞。有趣的是，我们是第一个报告ATG16L1是VDR的靶基因。缺乏肠上皮VDR是通过降低mRNA和ATG16L1的蛋白质水平来实现的。因此，我们假设肠上皮VDR是IBD风险通过其在肠细胞功能和肠内稳态中微生物组合的作用来确定的。现在，我们开发了新型的实验模型，以研究严重影响肠道功能和肠子菌群的VDR作用。 AIM 1将测试肠上皮VDR确定Paneth细胞和自噬的功能的工作假设，从而改变了炎症中的肠道菌群。我们将在VDRΔIEC和VDRΔPANETH细胞小鼠中阐明肠上皮VDR如何导致异常的paneth细胞（分化和改善的AMP）； b）使用类器官和VDR转基因小鼠，通过细胞凋亡/自噬平衡来确定VDR对自噬调节剂的影响和机制； c）研究使用器官和TG-I-I-VDR小鼠的肠道VDR的过表达是否可以恢复泛细胞和自噬。 AIM 2将检验以下假设：调节微生物组和恢复VDR功能的平衡，微生物组将恢复功能，我们将：a）研究肠上皮VDR在通过粪便中通过粪便移植或重殖当时在最初的无生殖小鼠中施用时肠上皮VDR在改变细菌群体中的作用； b）定义强迫肠道VDR表达在恢复微生物稳态的效果和机制，但通过paneth细胞和IL10 - / - 结肠炎小鼠中的自噬调节。我们的研究之所以创新，是因为它们提供了一个统一的假设，该假设可能会说明自噬，异常paneth细胞以及许多IBD和肠道疾病患者发现的失调。这些见解将导致预防和治疗IBD和肠道疾病的新型策略。