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）：革兰氏阴性细菌弧菌霍乱，霍乱的病原体，是一种位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在感染过程中产生疾病所需的许多毒力因子。然而，霍乱弧菌在从其海洋生态系统到人类宿主的过渡和感染的发展时如何改变其基因表达。我们发现，转录因子APHB具有半胱氨酸残基，该残基对肠道的微毒条件进行了修饰，从而导致毒力的激活。现在，我们有进一步的证据表明，通过基因转录和蛋白质稳定性的变化，APHB中各种半胱氨酸的修饰会导致对细胞生理的各种影响。我们假设APHB是与霍乱弧菌感染相关的环境信息的中心处理器。具体而言，我们假设APHB使用硫醇修饰将还原性，氧化和硝化反应物的存在整合到引导生物体进入和流入人类肠道所需的基因表达决策中。我们将使用生化和遗传技术的混合物来机械定义APHB如何协调V.霍乱的致病生命周期以及在此基于半胱氨酸的感觉枢纽中还涉及哪些其他因素。我们认为，通过全面定义APHB监视V.霍乱的化学微环境的方式，我们可能能够将基于半胱氨酸的环境传感的范式扩展到其他V.霍乱蛋白和其他病原体。我们将研究APHB如何通过反应性氮种（RN）（例如一氧化氮（NO）以及体内产生的活性氧（ROS）的氧化应激以及这些修饰如何影响APHB功能的氧化应激。我们将研究APHB修饰对细胞生理学的广泛影响，重点是ROS/RNS应力管理，考虑到以下模型：进入肠道后，降低APHB会激活毒力，以响应低氧张力；响应于肠道中的化学应力增加，修饰的APHB在上调ROS和RNS排毒的同时停用了毒力，从而为在水生环境中的生存准备了细胞的生存。