Intracellular Bacterial Recognition in the Drosophila Innate Immune Response

果蝇先天免疫反应中的细胞内细菌识别

• 批准号: 8032533
• 负责人: Neal Silverman
• 金额: $ 28.16万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8032533
• 关键词: Animals; Autophagocytosis; Bacteria; Binding; Biotin; Caspase-1; Cell surface; Cells; Crohn' s disease; Cytosol; Disease; Drosophila genus; Familial amyloid nephropathy with urticaria and deafness; Family; Feedback; Flagellin; Genes; Germ; Growth; Human; Hybrids; Immune; Immune response; Immune system; Immunologic Receptors; Infection; Infection Control; Inflammatory; Inflammatory Response Pathway; Injection of therapeutic agent; Insecta; Interleukin-12; Ligands; Link; Listeria; Listeria monocytogenes; Listeriosis; Mammals; Mediating; Molecular; Mutation; Natural Immunity; Organ; Output; Pathway interactions; Peptidoglycan; Plant Roots; Play; Process; Protein Family; Proteins; Reaction; Role; Series; Signal Pathway; Signal Transduction; System; Tissues; fly; in vivo; inhibitor/antagonist; microbial; pathogen; public health relevance; receptor; receptor binding; response; vaccine effectiveness

DESCRIPTION (provided by applicant): Intracellular microbial recognition plays a critical role in innate immunity. Small fragments of bacterial peptidoglycan as well as bacterial flagellin are known to stimulate the NOD-like Receptors in mammals. This family of receptors includes both the NOD proteins, which respond to peptidoglycan fragments by activating NF-?B, and the NALP family of proteins, which respond to peptidoglycan, flagellin and other danger signals by activating IL-12 processing and release. Animals deficient in these receptors are hypersusceptible to infection, while humans carrying mutations in NOD2 and NALP3 suffer from autoinflammatory Crohn's disease and Muckle Wells Syndrome. Despite advances, it has not yet been demonstrated that any of these putative intracellular innate immune receptors directly recognize their cognate ligand, nor is it clear how these intracellular receptor transduce signals or how the induced responses contribute to efficient immune protection. In Drosophila, we have recently established that analogous intracellular microbial recognition occurs. Upon injection into flies, small fragments of peptidoglycan are recognized by the intracellular receptor PGRP-LE. Moreover, PGRP-LE directly binds these monomeric fragments of peptidoglycan causing receptor oligomerization. In addition to small fragments of peptidoglycan, PGRP-LE also recognizes cytosolic bacteria, like Listeria monocytogenes, and this recognition is critical to block bacterial growth. These results have led us to hypothesize that PGRP-LE functions as an intracellular receptor capable of recognizing peptidoglycan that enters cells, triggering receptor oligomerization, intracellular signaling and ultimately protective immune responses. We propose a series of 3 Aims that will probe in molecular detail the role of PGRP-LE and intracellular bacterial recognition in producing effective immune responses. Aim 1 will determine which organs, cells and subcellular compartments are involved in the PGRP-LE-mediated response to monomeric peptidoglycan. Aim 2 will characterize the molecular mechanisms of PGRP-LE-mediated signal transduction. The function of ligand-induced receptor oligomerization will be analyzed in vivo; the different responses emanating from intracellular versus cell-surface immune recognition will be probed; and a direct feedback inhibitor of these peptidoglycan binding receptors will be characterized. Aim 3 will analyze the role of PGRP-LE in the response to pathogens that release large quantities of monomeric peptidoglycan. And the role of PGRP-LE in controlling infection by intracellular Listeria monocytogenes will be thoroughly characterized. Autophagy is critical for the control of Listeria and we will determine if PGRP-LE- mediated recognition is required for the induction of this protective response. In people, the innate immune response is absolutely critical for the rapid protection against germs and for the effectiveness of vaccines. In addition, uncontrolled innate immune reactions are often the root cause of auto-inflammatory diseases. Insects, such as the fruit fly, rely entirely on innate immune responses that are very similar to our own innate immune system, and this proposal aims to use the fruit fly, a powerful experimental system, for the study of innate immunity. PUBLIC HEALTH RELEVANCE: In people, the innate immune response is absolutely critical for the rapid protection against germs and for the effectiveness of vaccines. In addition, uncontrolled innate immune reactions are often the root cause of auto-inflammatory diseases. Insects, such as the fruit fly, rely entirely on innate immune responses that are very similar to our own innate immune system, and this proposal aims to use the fruit fly, a powerful experimental system, for the study of innate immunity.

描述(申请人提供)：细胞内微生物识别在先天免疫中起着关键作用。众所周知，细菌肽聚糖的小片段以及细菌鞭毛蛋白可以刺激哺乳动物的点状受体。这一受体家族既包括NOD蛋白和NALP蛋白，前者通过激活核因子-β对肽聚糖片段作出反应，后者通过激活IL-12的处理和释放对肽聚糖、鞭毛蛋白和其他危险信号作出反应。缺乏这些受体的动物对感染过敏，而携带NOD2和NALP3突变的人类则患有自发性炎症性克罗恩病和Muckle Wells综合征。尽管取得了进展，但尚未证明这些假定的细胞内天然免疫受体中的任何一个直接识别它们的同源配体，也不清楚这些细胞内受体如何转导信号或诱导的反应如何有助于有效的免疫保护。在果蝇中，我们最近证实了类似的细胞内微生物识别发生。当注射到果蝇体内时，小片段的肽聚糖被细胞内受体PGRP-LE识别。此外，PGRP-LE直接与这些肽聚糖单体片段结合，导致受体寡聚。除了肽聚糖的小片段外，PGRP-LE还识别胞质细菌，如单核细胞增多性李斯特菌，这种识别对于阻止细菌生长至关重要。这些结果使我们假设PGRP-LE是一种细胞内受体，能够识别进入细胞的肽聚糖，触发受体寡聚，细胞内信号转导，最终保护免疫反应。我们提出了一系列3个目标，将从分子细节上探讨PGRP-LE和细胞内细菌识别在产生有效免疫反应中的作用。目的1将确定哪些器官、细胞和亚细胞室参与了PGRP-LE介导的对单体肽聚糖的反应。目的2研究PGRP-LE介导的信号转导的分子机制。将在体内分析配体诱导的受体寡聚的功能；将探索细胞内免疫识别与细胞表面免疫识别的不同反应；并将表征这些肽聚糖结合受体的直接反馈抑制物。目的3将分析PGRP-LE在对释放大量单体肽聚糖的病原体的反应中的作用。而PGRP-LE在控制细胞内单核细胞增多性李斯特菌感染中的作用将被彻底表征。自噬对于李斯特菌的控制至关重要，我们将确定是否需要PGRP-le介导的识别来诱导这种保护性反应。在人体内，先天免疫反应对于快速抵御细菌和疫苗的有效性是绝对关键的。此外，不受控制的先天免疫反应往往是自发性炎症性疾病的根源。昆虫，如果蝇，完全依赖于与我们自己的先天免疫系统非常相似的先天免疫反应，这一提议旨在利用果蝇这一强大的实验系统来研究先天免疫。 与公共卫生相关：在人类中，先天免疫反应对于快速抵御细菌和疫苗的有效性是绝对关键的。此外，不受控制的先天免疫反应往往是自发性炎症性疾病的根源。昆虫，如果蝇，完全依赖于与我们自己的先天免疫系统非常相似的先天免疫反应，这一提议旨在利用果蝇这一强大的实验系统来研究先天免疫。