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 我们有了一个意想不到的发现，发酵有助于沙门氏菌的抗氧化防御， 这一观察结果对防御氧化应激具有广泛的意义，远远超出了细菌的范畴。 感染性腹泻每年折磨着10亿人，占人类死亡总数的4%。其中许多 感染是由2500个非伤寒沙门氏菌血清型之一引起的，这种沙门氏菌可以造成生命- 威胁着非常年轻、非常年长和感染艾滋病毒的人的全身并发症。氧化应激 来自NADPH氧化酶的酶活性是最强大的寄主防御之一 沙门氏菌在与专业吞噬细胞接触过程中的面部。随之而来的遗传毒性 Fenton介导的DNA双链断裂与细胞功能障碍有关的氧化 蛋白质中的半胱氨酸残基和金属辅因子构成了氧化应激致死的范例 沙门氏菌和许多其他细菌病原体。然而，尽管它们在抵抗 沙门氏菌病，各种机制的相对重要性，通过不同的机制，通过活性氧物种造成的抗 人们对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 对抗氧化应激同样是肤浅的。对过氧化氢反应的突变体筛选，过氧化氢是 NADPH氧化酶最重要的效应因子，揭示了以前未预料到的中枢代谢作用 以及过氧化氢介导的杀灭沙门氏菌的电子传输链。我们的初步数据 提示细胞被膜蛋白氧化和胞浆溶解样病变(即内外分离 在氧化应激期间杀死沙门氏菌的步骤是以前未被怀疑的步骤。这些 研究为NADPH氧化酶如何产生强大的抗沙门氏菌活性提供了一个创新的框架 在巨噬细胞的先天反应中。我们将检验这样的假设：发酵有助于 沙门氏菌通过协助ATP合成、平衡氧化还原和启动二硫键来进行抗氧化防御 在周质蛋白中形成，从而保护细胞被膜免受活性氧的致命损害 由NADPH氧化酶产生的物种。具体地说，我们将描述发酵在 伤寒和非伤寒沙门氏菌的抗氧化防御，阐明氧化的机制 压力促进发酵，并决定细胞内沙门氏菌如何被NADPH氧化酶杀死。不 这些知识不仅将阐明沙门氏菌发病机制的关键方面，而且还应提供对 不同沙门氏菌血清型的独特和共享的抗氧化防御。我们的研究最终可能会有一个 对各种领域的影响，从微生物发病机制、衰老、糖尿病或癌症生物学，到氧化 压力是一种内在成分。特定抑制细菌糖酵解酶和发酵的药物 途径可能导致新的抗生素治疗方法的发展。未来的沙门氏菌对策可能 也要探索增加呼吸活动的策略，以此作为煽动氧化死亡的手段。