Mechanisms of gut epithelial DUOX-mediated intestinal homeostasis

项目总结/摘要 单层的肠上皮细胞覆盖肠腔，阻止针对 正常的肠道微生物群，同时控制可能危及生命的感染 病原体这种平衡关系的破坏可导致食源性感染和慢性肠道疾病。 炎症活性氧化物质（ROS）在粘膜宿主防御中起关键作用，但也有助于 煽动性的环境。经典的NOX 2/gp 91 phox NADPH氧化酶的保护性宿主防御作用， 负责巨噬细胞的氧化爆发反应，已被广泛研究，但 另一种NADPH氧化酶，双氧化酶（DUOX）不太清楚。我们的长期目标是确定 DUOX 2是DUOX在肠上皮中表达的唯一形式，在上皮防御中维持粘膜保护， 体内平衡目的是确定DUOX 2如何保护上皮细胞免受侵入性细菌的侵害。 产生抗氧化酶来保护自己不受H2 O2伤害。我们的假设是， 通过细菌附着的DUOX 2对于正确处理被吞噬的细菌以维持微生物的生长至关重要。 宿主体内平衡这项研究的基本原理是，一旦知道DUOX 2是如何编排的， 为了增强肠上皮中的粘膜宿主防御，可以选择特定的药物治疗剂来增强 DUOX介导的细菌处理，导致预防和治疗各种 与细菌移位增加相关的胃肠道疾病。我们将测试我们的中心假设， 从而通过追求以下具体目的来实现本申请的目的：1.探讨 粘膜相关细菌诱导DUOX 2的机制，2.定义DUOX 2的作用， 肠道病原体的细胞自主控制。3.研究DUOX 2的含义 缺乏对IBD的易感性。预期的成果，拟议的工作，预计将阐明一个 DUOX 2如何响应细菌-上皮接触而被激活的机制框架，支持细胞- 细胞内细菌的自主失活，从而维持免疫稳态。这样的结果 预计将产生重要的积极影响，因为这种免疫机制极有可能提供 与失调微生物相关疾病的预防和治疗干预的新目标- 肠道相互作用（例如，IBD，IBS，结肠癌），除了从根本上推进肠道领域 粘膜免疫它还将为与DUOX 2 LOF相关的IBD发病机制提供急需的见解 从而为更好地为这些患者制定治疗计划奠定基础。

PROJECT SUMMARY/ABSTRACT A monolayer of gut epithelial cells covers the intestinal lumen preventing an overt immune response against the normal gut microbiota, while at the same time controlling infection with potentially life-threatening pathogens. Breakdown of this homeostatic relationship can lead to foodborne infections and chronic intestinal inflammation. Reactive oxidative species (ROS) play a critical role in mucosal host defense but also contribute to the inflammatory milieu. The protective host defense role of the classical NOX2/gp91phox NADPH oxidase, responsible for the oxidative burst reaction of macrophages, has been extensively researched, but the role of another NADPH oxidase, dual oxidase (DUOX) is less clear. Our long-term objective is to define the role of DUOX2, the only form of DUOX expressed in the gut epithelium, in epithelial defense to maintain mucosal homeostasis. The objective here is to determine how DUOX2 can protect epithelial cells from invasive bacteria that produce antioxidative enzymes to shield themselves from H2O2. Our hypothesis is that activation of DUOX2 by bacterial attachment is critical for proper handling of engulfed bacteria to maintain microbe- host homeostasis. The rationale for the proposed research is that, once it is known how DUOX2 orchestrates mucosal host defense in the intestinal epithelium, specific pharmacotherapeutics can be selected to enhance DUOX-mediated bacterial handling, resulting in new approaches to the prevention and treatment of a variety of GI disorders associated with increased bacterial translocation. We will test our central hypothesis and, thereby, accomplish the objective of this application by pursuing the following specific aims: 1. Investigate the mechanisms of DUOX2 induction by mucosa-associated bacteria, 2. Define the role of DUOX2 in the cell-autonomous containment of intestinal pathogens. 3. Study the implications of DUOX2 deficiency for susceptibility to IBD. The expected outcomes, the proposed work is expected to elucidate a mechanistic framework how DUOX2 is activated in response to bacteria-epithelial contact, supports cell- autonomous inactivation of intracellular bacteria, and, thereby, maintains immune homeostasis. Such results are expected to have an important positive impact because this immune mechanism is highly likely to provide new targets for preventative and therapeutic interventions for diseases associated with dysregulated microbe- intestinal interaction (e.g., IBD, IBS, colon cancer) in addition to fundamentally advancing the fields of gut mucosal immunity. It will also provide much-needed insight into the pathogenesis of IBD linked to DUOX2 LOF and thus the foundation to better strategize a treatment plan for these patients.