Role of Dendritic Cells in H pylori-induced Treg-mediated Host Immune Tolerance

描述（由申请方提供）：粘液素对管腔微生物的免疫耐受是一个高度调节的过程，缺乏该过程会导致胃肠道慢性炎症。H.幽门螺杆菌是一种胃病原体，能够在<15%的感染个体中引起严重的慢性胃炎和溃疡，但大多数发展为没有症状的轻度胃炎。该提案的长期目标是了解胃粘膜耐受的机制。我们将在K 08资助期间研究树突状细胞（DCs）介导的H。pylori免疫逃逸，利用H. pylori定植模型研究胃粘膜耐受性。我们的初步研究结果支持的概念，即Hp诱导的调节性T细胞（T细胞）是由DC介导的。因此，我们假设H. pylori通过IRAK-M介导的TGF-2依赖性机制与DC相互作用，从而触发宿主耐受性应答，该机制改变了H. pylori T效应细胞/Treg平衡导致宿主对H.幽门螺杆菌和慢性定植。目的1）明确组织DC在H.幽门耐药性。在急性H. pylori感染及其机制。幽门螺杆菌的摄取和淋巴结迁移的DC将阐明。H. pylori摄取和耐受诱导将使用DC消融进行研究。目的2）研究DC TLR和细胞内调节剂在致耐受性DC编程中的作用。首先，我们将确定H。pylori刺激的DCs诱导TcB需要免疫原性H.幽门。接下来，将探索IRAK-M在Treg诱导中的作用。还将使用H探索TLR 9的作用。pylori DNA刺激和TLR 9缺失小鼠。目的3）分析DC-Treg的诱导在调节H.幽门耐药性。我们将使用体内过继转移H。pylori刺激的BMDCs，诱导H. pylori特异性T细胞亚群，然后使用CD 25中和抗体研究Treg耗竭对H.幽门耐药性。Th 1和Th 17细胞在H.使用IFN-3和Th 17 A缺失小鼠研究幽门螺杆菌耐受性。调节TGF-2对H.将使用过表达TGF-2或产生在微环境中中和DC的TGF-2受体的细胞系来研究幽门螺杆菌刺激的DC。这项建议的健康相关性是了解粘膜耐受H的机制。幽门螺杆菌开始解决导致耐受性降低的因素。本项目的发现不仅为了解胃粘膜对腔菌的耐受机制提供了新的见解，而且也加深了我们对胃免疫区室耐受发展的理解。通过靶向DC调节机制或通过使用细菌产物（例如，益生元、益生菌）。 公共卫生相关性：该建议的健康相关性是为了了解粘膜耐受性的机制，以便开始解决导致耐受性破坏的因素。本项目的发现不仅为了解胃粘膜对腔菌的耐受机制提供了新的见解，而且也加深了我们对胃免疫区室耐受发展的理解。通过靶向DC调节机制或通过使用细菌产物（例如，益生元、益生菌）。

DESCRIPTION (provided by applicant): Mucosal immune tolerance to luminal microbes is a highly regulated process a lack of which leads to chronic inflammation of the GI tract. H. pylori is a gastric pathogen able to cause severe chronic gastritis and ulcers in <15% of infected individuals, but the majority developed a mild gastritis without symptoms. The long-term objective of this proposal is to understand the mechanisms of mucosal tolerance in the stomach. We will build on our observations made during the K08 funding period studying the dendritic cells (DCs)-mediated mechanism of H. pylori immune escape and use the H. pylori colonization model to study gastric mucosal tolerance. Our preliminary results support the notion that Hp induction of regulatory T cells (Tregs) is mediated by DCs. Therefore, we hypothesize that H. pylori triggers a host tolerogenic response by interacting with DCs via a IRAK-M-mediated, TGF-2-dependent mechanism which alters the H. pylori Teffector/Treg balance leading to the development of host tolerance to H. pylori and chronic colonization. The specific aims are: Aim 1) To Determine the role of tissue DCs in H. pylori tolerance. DC subset in the stomach will be characterized during acute H. pylori infection and mechanism of H. pylori uptake and lymph node migration by DC will be elucidated. The requirement of DCs in H. pylori uptake and tolerance induction will be studied using DC ablation. Aim 2) Investigate the role of DC TLR and intracellular modulators of tolerogenic DC programming. First we will determine whether H. pylori stimulated DCs induce Tregs requires immunogenic H. pylori. Next, the role of IRAK-M in Treg induction will be explored. The role of TLR9 will also be explored using H. pylori DNA stimulation and TLR9 null mice. Aim 3) To analyze the role of DC-Treg induction in modulating H. pylori tolerance. We will use in vivo adoptive transfer of H. pylori-stimulated BMDCs into mice to induce H. pylori- specific Tregs and then use CD25 neutralizing antibodies to study the effect of Treg depletion on H. pylori tolerance. The role of Th1 and Th17 cells in H. pylori tolerance will be studied using IFN-3 and Th17A null mice. The effect of modulation TGF-2 on Treg induction by H. pylori stimulated DCs will be studies using cell lines over-expressing TGF-2 or produces a TGF-2 receptor that neutralizes DCs in the microenvironment. The health relatedness of this proposal is to understand the mechanism of mucosal tolerance to H. pylori to begin to address the factors that lead to reduced tolerance. The finding of this project will provide not only provide novel insight into the mechanism of mucosal tolerance to luminal bacteria, but also enhance our understanding of the development of tolerance in the gastric immune compartment. New targets may be discovered useful for designing therapies to restored immune homeostasis in patients with chronic inflammatory conditions by targeting DCs regulatory mechanisms or by using bacterial products (e.g., prebiotics, probiotics). PUBLIC HEALTH RELEVANCE: The health relatedness of this proposal is to understand the mechanism of mucosal tolerance in order to begin to address the factors that lead to a break in tolerance. The finding of this project will provide not only provide novel insight into the mechanism of mucosal tolerance to luminal bacteria, but also enhance our understanding of the development of tolerance in the gastric immune compartment. New targets may be discovered useful for designing therapies to restored immune homeostasis in patients with chronic inflammatory conditions by targeting DCs regulatory mechanisms or by using bacterial products (e.g., prebiotics, probiotics).