Molecular mechanisms supporting bacterial survival within immune cells

支持免疫细胞内细菌存活的分子机制

• 批准号: 10872599
• 负责人: Maria Ramona Neunuebel
• 金额: $ 23.94万
• 依托单位: UNIVERSITY OF DELAWARE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10872599
• 关键词: Acceleration; Address; Affinity; Amino Acids; Antibiotics; Bacteria; Bacterial Proteins; Binding; Binding Proteins; Biology; Cell membrane; Cells; Chemicals; Collaborations; Complex; Confocal Microscopy; Copper; Critical Pathways; Crystallization; Cyclooctenes; Cytosol; Disease; Endoplasmic Reticulum; Ensure; Face; Foundations; Genetic Diseases; Goals; Golgi Apparatus; Gram-Negative Bacteria; Head; Human; Immune; Immunity; Individual; Infection; Inositol; Intervention; Knowledge; Label; Legionella; Legionella pneumophila; Legionnaires' Disease; Ligands; Lipid Binding; Lipids; Lung; Lysosomes; Macrophage; Maps; Mediating; Membrane; Membrane Protein Traffic; Modeling; Molecular; Molecular Target; Mutation Analysis; Organelles; Outcome; Pathway interactions; Persons; Phase; Phosphatidylinositols; Phosphorylation; Plasma Cells; Pneumonia; Positioning Attribute; Proteins; Public Health; Reaction; Research; Site; Specificity; Surface Plasmon Resonance; System; Testing; Therapeutic; Time; Transmembrane Transport; Transport Process; Travel; Vacuole; Vesicle; Virulence; Work; X-Ray Crystallography; combat; drinking water; efflux pump; fluorophore; improved; insight; myoinositol; novel; pathogen; pathogenic bacteria; permissiveness; prevent; protein complex; public drinking; recruit; spatiotemporal; trafficking

PROJECT SUMMARY Gram-negative bacteria are increasingly challenging to combat because existing antibiotics struggle to reach their intracellular targets and face elimination by efflux pumps. This issue is particularly pressing for bacteria that establish a replication-permissive vacuole derived from the host's plasma membrane. Shielded by multiple layers of membranes, intracellular pathogens become inaccessible to traditional antibiotics. A fundamental gap persists in the current understanding of how bacterial pathogens subvert host membrane transport processes and continued existence of this gap impedes our understanding of mechanisms that bacterial pathogens use to coordinate virulence strategies. Our long-term goal is to address this gap by systematically unveiling the host pathways critical for infection of human lung macrophages by the bacterial pathogen Legionella pneumophila, the causative agent of a severe pneumonia known as Legionnaires' disease. Legionella infects lung macrophages and resists degradation by establishing and residing within a membrane-bound compartment known as the Legionella-containing vacuole. Initially derived from the host cell's plasma membrane, this vacuolar membrane is dramatically remodeled during infection. To do so, the bacterium immediately begins translocating a large number of (effector) proteins directly into the host cytosol. The host membrane trafficking network is a major target of L. pneumophila effector proteins. In particular, vesicles traveling between the endoplasmic reticulum and the Golgi are sequestered by the Legionella-containing vacuole early during infection, whereas fusion with degradative lysosomes is prevented. These observations support the working model that the pathogen orchestrates its molecular interactions with the host to stimulate or inhibit fusion of host vesicles with its vacuole. Delineating the spatiotemporal distribution of secreted effectors is a critical step to understanding how L. pneumophila interacts with the host cell to ensure its own survival. The overall objective is to examine the spatiotemporal localization of L. pneumophila effector proteins in the context of human macrophage infection and to determine how L. pneumophila effectors interact with host phosphoinositide lipids to target membrane compartments. We propose: (1) to use a dual pronged approach based on chemical biology to directly track localization of L. pneumophila effectors in infected human macrophages, and (2) to characterize the protein-lipid interface between L. pneumophila effectors identified in our preliminary screen using X-ray crystallography. The proposed research is significant because it is positioned to advance our understanding of how bacterial pathogens manipulate host membrane transport pathways to promote intracellular survival of bacteria. A significant collateral outcome is that these studies could suggest new molecular targets for intervention in L. pneumophila infections and related conditions.

项目摘要 革兰氏阴性菌越来越具有挑战性，因为现有的抗生素难以达到 它们的细胞内靶点和面对通过外排泵消除。这个问题对细菌来说尤其紧迫 从宿主的质膜上建立起允许复制的空泡。多重屏蔽 细胞膜层，细胞内的病原体变得难以接近传统的抗生素。一个根本性的差距 坚持目前对细菌病原体如何破坏宿主膜转运过程的理解 这种差距的持续存在阻碍了我们对细菌病原体用于 协调毒力策略。我们的长期目标是通过系统地揭示主机， 嗜肺军团菌感染人肺巨噬细胞的关键途径， 一种叫做军团病的严重肺炎的病原体。军团菌感染肺部 巨噬细胞，并通过建立和驻留在膜结合区室中来抵抗降解 即含有军团菌的空泡。最初来源于宿主细胞的质膜， 在感染过程中，空泡膜显著重塑。为了做到这一点，细菌立即开始 将大量（效应）蛋白直接转运到宿主细胞质中。宿主细胞膜运输 网络是L.嗜肺菌效应蛋白。特别是，囊泡在 内质网和高尔基体被含军团菌的空泡隔离， 感染，而与降解性溶酶体的融合被阻止。这些观察结果支持了 病原体协调其与宿主的分子相互作用，以刺激或抑制 寄主小泡和它的液泡。描绘分泌效应物的时空分布是关键的一步 了解L.嗜肺菌与宿主细胞相互作用以确保其自身存活。整体 目的是研究L.嗜肺菌效应蛋白的背景下， 人类巨噬细胞感染并确定L.嗜肺菌效应子与宿主相互作用 磷酸肌醇脂质靶向膜隔室。我们建议：（1）双管齐下 基于化学生物学直接追踪L.感染者中的嗜肺菌效应子 巨噬细胞，和（2）表征L.嗜肺效应子 用X射线晶体学进行初步筛选这项研究之所以重要，是因为 定位于推进我们对细菌病原体如何操纵宿主膜运输的理解 促进细菌细胞内存活的途径。一个重要的附带结果是，这些研究 可能为L.嗜肺菌感染和相关病症。