Molecular determinants of oxidative stress in Salmonella pathogenesis

沙门氏菌发病机制中氧化应激的分子决定因素

• 批准号: 10222502
• 负责人: Andres Vazquez-Torres
• 金额: $ 42.95万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-24 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10222502
• 关键词: ATP Synthesis Pathway; Acetates; Aging; Animal Model; Antibiotic Therapy; Antioxidants; Attenuated; Bacteria; Cancer Biology; Carbon; Cell membrane; Cell model; Cells; Cessation of life; Communicable Diseases; Cysteine; Cytochrome c Reductase; DNA Double Strand Break; Data; Development; Diabetes Mellitus; Diarrhea; Disease; Disulfides; Electron Transport; Enzymes; Equilibrium; Face; Fermentation; Future; Genes; Glutathione; Glycolysis; HIV; Host Defense; Human; Hydrogen Peroxide; Individual; Infection; Investigation; Knowledge; Lead; Learning; Lesion; Libraries; Life; Light; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Membrane; Metabolic; Metabolism; Metals; Modeling; Molecular; Mus; Mutation; NADH; NADH dehydrogenase (ubiquinone); NADP; NADPH Oxidase; Oxidases; Oxidation-Reduction; Oxidative Stress; Oxidoreductase; Pathogenesis; Pathogenicity; Pathway interactions; Pentosephosphate Pathway; Periplasmic Proteins; Phagocytes; Pharmaceutical Preparations; Phosphoglycerate Mutase; Phosphotransferases; Play; Process; Proteins; Reactive Oxygen Species; Research; Resistance; Role; Salmonella; Salmonella enterica; Salmonella infections; Succinates; TXN gene; Testing; Typhoid Fever; Virulent; antimicrobial; cell envelope; cofactor; combat; deep sequencing; disulfide bond; env Gene Products; fighting; genotoxicity; in vivo; innovation; insight; macrophage; metabolomics; microbial; microorganism; mutant; novel; oxidation; oxidative damage; pathogenic bacteria; periplasm; respiratory; response; single cell analysis

PROJECT SUMMARY/ ABSTRACT We have made the unexpected discovery that fermentation contributes to Salmonella's antioxidant defenses, an observation with wide ranging implications for defense against oxidative stress, well beyond bacteria. Infectious diarrhea afflicts a billion people a year and is responsible for 4% of all human deaths. Many of these infections are caused by one of the 2,500 serovars of nontyphoidal Salmonella enterica, which can inflict life- threatening systemic complications in the very young, very old, and HIV-infected individuals. Oxidative stress emanating from the enzymatic activity of the NADPH oxidase is one of the most potent host defenses Salmonella face during their associations with professional phagocytic cells. Genotoxicity that ensues from Fenton-mediated DNA double strand breaks together with cellular malfunctions associated with the oxidation of cysteine residues and metal cofactors in proteins constitute the paradigm for how oxidative stress kills Salmonella and numerous other bacterial pathogens. However, despite their central role in resistance to salmonellosis, the relative importance of the various mechanisms by which reactive oxygen species inflict anti- Salmonella activity is poorly understood. Our understanding of the adaptive responses that protect Salmonella against oxidative stress is similarly superficial. A screen of mutants in response to hydrogen peroxide, one of the most important effectors of the NADPH oxidase, revealed previously unanticipated roles for central metabolism and the electron transport chain in the hydrogen peroxide-mediated killing of Salmonella. Our preliminary data suggest oxidation of cell envelope proteins and plasmolysis-like lesions (i.e., separation of inner and outer membranes) as previously unsuspected steps in the killing of Salmonella during oxidative stress. These investigations offer an innovative framework for how NADPH oxidase inflicts potent anti-Salmonella activity during the innate response of macrophages. We will test the hypothesis that fermentation contributes to Salmonella's antioxidant defenses by assisting with ATP synthesis, balancing redox, and enabling disulfide bond formation in periplasmic proteins, thereby protecting the cell envelope from lethal damage by reactive oxygen species generated by the NADPH oxidase. Specifically, we will characterize the role fermentation plays in the antioxidant defenses of typhoidal and nontyphoidal Salmonella, elucidate the mechanism by which oxidative stress promotes fermentation, and determine how intracellular Salmonella is killed by the NADPH oxidase. Not only will this knowledge illuminate key aspects of Salmonella pathogenesis, but should also provide insights into unique and shared antioxidant defenses of various Salmonella serovars. Our research could ultimately have an impact on fields as diverse as microbial pathogenesis, aging, diabetes, or cancer biology for which oxidative stress is an intrinsic component. Drugs that specifically inhibit bacterial glycolytic enzymes and fermentative pathways may lead to the development of novel antibiotic treatments. Future Salmonella countermeasures could also explore strategies that increase respiratory activity as a means to foment oxidative killing.

项目摘要/摘要 我们已经意外发现的是，发酵有助于沙门氏菌的抗氧化剂防御， 一种对防御氧化应激的影响，远远超出了细菌的观察。 感染性的腹泻每年遭受10亿人的痛苦，造成了所有人类死亡的4％。其中许多 感染是由2500种非细类沙门氏菌之一引起的，可以造成生命 - 威胁年轻，非常古老和感染HIV的人的系统并发症。氧化应激 从NADPH氧化酶的酶活性发出的是最有效的宿主防御力之一 沙门氏菌与专业吞噬细胞的关联期间。遗传毒性从 芬顿介导的DNA双链与与氧化有关的细胞故障破裂 蛋白质中的半胱氨酸残基和金属辅因子构成氧化应激如何杀死的范式 沙门氏菌和许多其他细菌病原体。但是，尽管它们在抵抗中的核心作用 沙门氏菌病，各种机制的相对重要性，这种机制被活性氧造成抗 沙门氏菌的活动知之甚少。我们对保护沙门氏菌的适应性反应的理解 抗氧化应激类似地是表面的。一个突变体响应过氧化氢的屏幕，其中之一 NADPH氧化酶的最重要效应子，揭示了以前意外的中央代谢作用 以及过氧化氢介导的沙门氏菌杀死的电子传输链。我们的初步数据 提示细胞包膜蛋白和浆液样病变的氧化（即内部和外部分离 膜）作为以前在氧化应激期间杀死沙门氏菌的步骤。这些 调查为NADPH氧化酶如何施加有效的抗盐分活性提供了创新的框架 在巨噬细胞的先天反应中。我们将检验以下假设，即发酵有助于 通过协助ATP合成，平衡氧化还原并实现二硫键，沙门氏菌的抗氧化剂防御能力 周围蛋白质形成，从而通过活性氧保护细胞包膜免受致命损伤 NADPH氧化酶产生的物种。具体而言，我们将表征发酵作用在 伤寒和非细沙门氏菌的抗氧化剂防御，阐明了氧化的机制 应力促进发酵，并确定细胞内沙门氏菌如何被NADPH氧化酶杀死。不是 只有这种知识才能阐明沙门氏菌发病机理的关键方面，但也应为 各种沙门氏菌血清射手的独特和共享的抗氧化防御。我们的研究最终可能会有 对像微生物发病机理，衰老，糖尿病或癌症生物学等多样化的影响，氧化 压力是一种内在组成部分。专门抑制细菌糖酵解酶和发酵的药物 途径可能导致新型抗生素治疗的发展。未来沙门氏菌的对策可能 还探索增加呼吸活动的策略，以此作为引起氧化杀害的一种手段。