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Thiol-based switches in Vibrio cholerae pathogenesis

霍乱弧菌发病机制中的硫醇开关

基本信息

批准号：
8862374
负责人：
Jun Zhu
金额：
$ 20万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-06-05 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8862374
关键词：
Adult Affect Biochemical Genetics Cell Survival Cell physiology Cells Chemicals Cholera Country Cysteine Disease Drug Metabolic Detoxication Ecosystem Environment Family Gene Expression Gene Expression Regulation Gene Proteins Genes Genetic Programming Genetic Techniques Genetic Transcription Goals Gram-Negative Bacteria Haiti Health Homo Human Immune response Immune system In Vitro Infection Intestines Lead Life Life Cycle Stages Light Marines Mind Modeling Modification Monitor Mus Mutation Nitric Oxide Nitrogen Organism Oxidative Stress Oxygen Oxygen measurement, partial pressure, arterial Pathogenesis Poverty Proteins Reactive Nitrogen Species Reactive Oxygen Species Repression Resistance Sensory Serine Stress Sulfhydryl Compounds Techniques Time Vibrio Vibrio cholerae Virulence Virulence Factors base coping design in vivo mouse model novel pathogen response stress management transcription factor

项目摘要

DESCRIPTION (provided by applicant): The Gram-negative bacterium Vibrio cholerae, the causative agent of cholera, is a facultative pathogen that resides in both human and aquatic environments. Extensive in vitro studies have identified a number of virulence factors required to produce disease during infection. However, how V. cholerae alters its gene expression upon transition from its marine ecosystem to the human host and along progression of infection is largely unknown. We have discovered that the transcription factor AphB possesses a cysteine residue that undergoes modification in response to the microoxic conditions of the intestines, leading to activation of virulence. We now have further evidence that diverse cysteine modifications in AphB lead to diverse effects on cell physiology through changes in gene transcription and protein stability. We hypothesize that AphB is the central processor of environmental information relevant to infection for V. cholerae. Specifically, we hypothesize that AphB uses thiol modifications to integrate the presence of reductive, oxidative and nitrosative reactants into the gene expression decisions necessary to guide the organism in and out of the human gut. We will use a mix of biochemical and genetic techniques to define mechanistically how AphB orchestrates the pathogenic life cycle of V. cholerae and what other factors are involved at this cysteine-based sensory hub. We believe that by comprehensively defining the way AphB monitors the chemical microenvironment for V. cholerae, we then may be able to extend the paradigm of cysteine-based environmental sensing to other V. cholerae proteins and other pathogens. We will examine how AphB is modified by reactive nitrogen species (RNS), such as nitric oxide (NO), and oxidative stress from reactive oxygen species (ROS) generated in vivo and how these modifications affect AphB functionality. We will study the broad effects of AphB modification on cell physiology, focusing on ROS/RNS stress management with the following model in mind: upon entry to the gut, reduced AphB activates virulence in response to low oxygen tension; in response to increasing chemical stress in the gut, modified AphB deactivates virulence while up-regulating ROS and RNS detoxification, thus preparing the cell for survival in the aquatic environment.

描述（由申请人提供）：革兰氏阴性细菌霍乱弧菌是霍乱的病原体，是一种存在于人类和水生环境中的兼性病原体。广泛的体外研究已经确定了感染过程中产生疾病所需的许多毒力因子。然而，霍乱弧菌从海洋生态系统转移到人类宿主以及感染过程中如何改变其基因表达尚不清楚。我们发现转录因子 AphB 具有半胱氨酸残基，该残基会根据肠道微氧条件进行修饰，从而激活毒力。我们现在有进一步的证据表明，AphB 中的不同半胱氨酸修饰通过基因转录和蛋白质稳定性的变化对细胞生理学产生不同的影响。我们假设 AphB 是与霍乱弧菌感染相关的环境信息的中央处理器。具体来说，我们假设 AphB 使用硫醇修饰将还原性、氧化性和亚硝化反应物的存在整合到引导生物体进出人类肠道所需的基因表达决策中。我们将结合使用生化和遗传技术来从机制上定义 AphB 如何协调霍乱弧菌的致病生命周期，以及这个基于半胱氨酸的感觉中枢涉及哪些其他因素。我们相信，通过全面定义 AphB 监测霍乱弧菌化学微环境的方式，我们也许能够将基于半胱氨酸的环境传感范式扩展到其他霍乱弧菌蛋白和其他病原体。我们将研究 AphB 如何被活性氮 (RNS)（例如一氧化氮 (NO)）和体内产生的活性氧 (ROS) 产生的氧化应激所修饰，以及这些修饰如何影响 AphB 功能。我们将研究 AphB 修饰对细胞生理学的广泛影响，重点关注 ROS/RNS 应激管理，并考虑以下模型：进入肠道后，减少的 AphB 会响应低氧张力而激活毒力；为了应对肠道中不断增加的化学应激，修饰后的 AphB 会钝化毒力，同时上调 ROS 和 RNS 解毒，从而为细胞在水生环境中的生存做好准备。