Role of epithelial cell intrinsic vitamin A metabolism in regulating immune function in the gut

上皮细胞内在维生素A代谢在调节肠道免疫功能中的作用

基本信息

批准号：
9892004
负责人：
Shipra Vaishnava
金额：
$ 44.85万
依托单位：
BROWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9892004
关键词：
All-Trans-Retinol Bacteria Cells Coupled Crohn&apos s disease Cues Data Development Diet Disease Engineering Epithelial Epithelial Cells Epithelium Food Gene Expression Generations Genes Genetic Genetic Polymorphism Genetic Transcription Germ-Free Gnotobiotic Goals Homeostasis Human Immune Immune System Diseases Immune response Immunity Inflammatory Inflammatory Bowel Diseases Interleukins Intestines Knowledge Laboratories Link Mediating Metabolic Metabolic Pathway Metabolism Methodology Microbe Molecular Mucosal Immune Responses Mucosal Immunity Mucous Membrane Mus Nutrient Physiological Plant Roots Play Police Predisposition Process Production Regulation Retinoids Retinol dehydrogenase Risk Role Signal Transduction Source Testing Therapeutic Time Tissues Tretinoin Ulcerative Colitis Vitamin A Work absorption antimicrobial bacterial community base cell type commensal bacteria cytokine enteric pathogen genetic approach gut bacteria gut microbiota host-microbe interactions immune function inflammatory disease of the intestine innovation insight interleukin-22 intestinal epithelium microbial microbiota mouse model new therapeutic target novel novel strategies overexpression response tandem mass spectrometry uptake

项目摘要

PROJECT SUMMARY Vitamin A or retinol is amongst the most well characterized food-derived nutrients with diverse immune- modulatory roles. Deficiency in dietary vitamin A has not only been associated with immune dysfunctions in the gut, but also with several systemic immune disorders. To maintain sufficient levels of vitamin A, the body relies on the uptake of retinol from the intestinal lumen by intestinal epithelial cells or IECs. After uptake by IECs, retinol can either be processed for storage or be further metabolized into retinoic acid (RA). Even though IECs are at the center of Vitamin A metabolism and play a dominant role in controlling the fate of dietary vitamin A, our knowledge of how IEC intrinsic vitamin A metabolic machinery is regulated is extremely superficial. By comparing germ-free (GF) and conventional (CV) mice we demonstrate that gut bacteria play a critical role in modulating retinoic acid (RA) levels and expression of vitamin A metabolic machinery in the intestinal epithelium. Specifically, we find bacteria differentially regulate expression of retinol dehydrogenase 7 (rdh7), a key gene involved in conversion of retinol into RA in the intestinal epithelium. By employing genetic mouse models harboring a deletion in rdh7 in IECs, we establish that IEC intrinsic RA production regulates the levels of Interleukin IL-22, a key cytokine that controls barrier responses to gut bacteria. Our data demonstrates for the first time that gut bacteria-dependent RA synthesis is critical for regulating local immune responses. Current proposal seeks to understand the molecular mechanism by which gut bacteria regulate RA synthesis and vitamin A metabolic gene rdh7 in IECs (Aim1), establish the role of rdh7 expression in IECs in regulating RA-signaling in the gut (Aim 2) and determine the role of IEC-intrinsic vitamin A metabolism on host-microbe homeostasis via modulation of IL-22 levels in the gut (Aim 3). To accomplish these goals, we have developed innovative genetic approaches that enable us to conditionally delete or over-express rdh7 specifically in IECs. Further we propose to utilize novel methodologies such as monoassociated and gnotobiotic mouse models to delineate the bacterial cues that regulate RA generation in the intestinal epithelium. Our experimental methodology incorporates robust analytical approaches such as tandem mass-spectrometry (LC-MS/MS) that enables us to accurately determine the flux in vitamin A metabolic pathway in response to discrete bacterial cues. This work will be significant because it will establish mechanistic links between gut bacteria and intestinal epithelium intrinsic vitamin A metabolic pathway. Moreover, it will test the feasibility of manipulating mucosal immunity by bacterial modulation of IEC intrinsic vitamin A metabolism for therapeutic purposes.

项目概要维生素 A 或视黄醇是特征最明确的食品源性营养素之一，具有多种免疫功能调节作用。膳食维生素 A 缺乏不仅与免疫功能障碍有关肠道，但也与一些系统性免疫疾病有关。为了维持足够的维生素 A 水平，身体依靠肠上皮细胞或 IEC 从肠腔摄取视黄醇的影响。被 IEC 采纳后，视黄醇可以加工储存或进一步代谢成视黄酸（RA）。尽管 IEC 处于维生素 A 代谢的中心，在控制膳食维生素 A 的命运中发挥主导作用，我们对 IEC 内在维生素 A 代谢机制如何调节的了解非常肤浅。经过比较无菌（GF）和传统（CV）小鼠，我们证明肠道细菌在调节肠道中视黄酸 (RA) 水平和维生素 A 代谢机制的表达上皮。具体来说，我们发现细菌差异性地调节视黄醇脱氢酶 7 (rdh7) 的表达，视黄醇脱氢酶 7 参与肠上皮中视黄醇转化为 RA 的关键基因。通过使用基因小鼠 IEC 中 rdh7 缺失的模型，我们确定 IEC 内在 RA 生产调节水平白介素 IL-22 是一种控制肠道细菌屏障反应的关键细胞因子。我们的数据表明肠道细菌依赖性 RA 合成首次对调节局部免疫反应至关重要。目前的提案旨在了解肠道细菌调节 RA 合成的分子机制和IECs中维生素A代谢基因rdh7 (Aim1)，建立了IECs中rdh7表达的调节作用肠道中的 RA 信号传导（目标 2）并确定 IEC 内在维生素 A 代谢对宿主微生物的作用通过调节肠道内 IL-22 水平实现体内平衡（目标 3）。为了实现这些目标，我们开发了创新的遗传方法使我们能够有条件地删除或过度表达 rdh7，特别是在 IEC 中。此外，我们建议利用新的方法，例如单相关和无菌小鼠模型来描绘了调节肠上皮中 RA 生成的细菌信号。我们的实验方法结合了串联质谱 (LC-MS/MS) 等强大的分析方法，使我们能够准确确定维生素 A 代谢途径中响应离散细菌的通量提示。这项工作意义重大，因为它将建立肠道细菌和肠道细菌之间的机制联系。肠上皮内在维生素A代谢途径。此外，还将测试操纵的可行性通过细菌调节 IEC 内在维生素 A 代谢来实现粘膜免疫，以达到治疗目的。