Role of the Coxiella burnetii Cryptic Plasmid in Host Cell Parasitism

伯氏柯克斯体隐匿质粒在宿主细胞寄生中的作用

• 批准号: 8076267
• 负责人: Daniel E Voth
• 金额: $ 35.62万
• 依托单位: UNIV OF ARKANSAS FOR MED SCIS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8076267
• 关键词: Acute; Acute Disease; Address; Aerosols; Alveolar; Apoptosis; Area; Autophagosome; Bacterial Proteins; Binding; Biology; Cavia; Cell Culture Techniques; Cell Survival; Cell physiology; Cells; Cellular biology; Chromosomes; Chromosomes, Human, Pair 8; Chronic; Coxiella; Coxiella burnetii; Cytoplasm; Cytosol; DNA; Endocarditis; Event; F Box Domain; Genes; Goals; Golgi Apparatus; Human; Immune Sera; In Vitro; Individual; Infection; Kinesin; Lysosomes; Mammalian Cell; Mediating; Membrane; Methods; Modeling; Mononuclear; Mutation; Organelles; Organism; Outcome; Pathogenesis; Phagocytes; Plasmids; Play; Process; Production; Protein Binding; Protein Biosynthesis; Proteins; Q Fever; Research; Role; System; Therapeutic; Type IV Secretion System Pathway; Vacuole; Virulence; Virulence Factors; Zoonoses; combat; design; flu; in vivo; insight; novel; obligate intracellular parasite; parasitism; pathogen; public health relevance; research study; therapeutic target; trafficking

DESCRIPTION (provided by applicant): Coxiella burnetii is an intracellular bacterial pathogen and the etiologic agent of human Q fever, an acute debilitating flu-like illness that can progress to chronic endocarditis. Since its discovery over 70 years ago, mechanisms used by the pathogen to parasitize host cells remain poorly understood. During infection, C. burnetii actively regulates multiple host processes, including vesicular trafficking and cell survival. The bacterial proteins mediating these events are not known but are likely delivered to the host cytosol by a Dot/Icm type IV secretion system. The current application is designed to functionally characterize C. burnetii plasmid-encoded Dot/Icm substrates and define their role in virulence. All C. burnetii isolates either harbor a large cryptic plasmid or have plasmid sequences integrated into their chromosome, suggesting these molecules are critical for pathogen biology. Interestingly, we have identified six Dot/Icm substrates encoded by C. burnetii plasmid genes that are termed Coxiella plasmid effectors A - F (CpeA - F). Three of these proteins are conserved in all isolates and three are specific to the QpH1 plasmid from a human acute disease isolate. Aim 1 is designed to characterize the interaction of conserved CpeB and CpeD with autophagosomes and secretory organelles, respectively. Aim 2 will define requirements of all six plasmid effectors during infection. Additionally, this aim will identify effector binding host proteins and determine the requirement of these components for C. burnetii infection. Aim 3 will determine the requirement of the C. burnetii plasmid for pathogen virulence in both cell culture and a guinea pig infection model of Q fever. Collectively, the aims in the current application will provide needed insight into the mechanisms used by C. burnetii to efficiently parasitize host cells. These studies will also provide novel information regarding the role of the C. burnetii cryptic plasmid in pathogen virulence. PUBLIC HEALTH RELEVANCE: Coxiella burnetii is an intracellular bacterial pathogen that causes the zoonosis human Q fever, a debilitating acute disease that also presents as chronic endocarditis. Currently, C. burnetii virulence determinants are poorly understood. Characterization of C. burnetii proteins delivered to the host cytosol by the Dot/Icm type IV secretion system will provide candidate therapeutic targets to combat Q fever and will provide needed insight into the interactions between C. burnetii and its host. The goals of the proposed research are to 1) characterize the interaction of C. burnetii plasmid-encoded Dot/Icm substrates with host proteins and 2) determine the role of the plasmid in pathogen virulence.)

描述（由申请人提供）：伯纳蒂克希菌是一种细胞内细菌病原体和人类Q热的病原体，Q热是一种急性衰弱性流感样疾病，可发展为慢性心内膜炎。自70多年前被发现以来，病原体寄生于宿主细胞的机制仍然知之甚少。在感染过程中，伯氏梭菌积极调节多种宿主过程，包括囊泡运输和细胞存活。介导这些事件的细菌蛋白尚不清楚，但可能是通过Dot/Icm IV型分泌系统传递到宿主细胞质中。目前的应用程序旨在功能表征伯氏梭菌质粒编码的Dot/Icm底物，并确定其在毒力中的作用。所有伯纳蒂胞杆菌分离株要么含有一个大的隐质粒，要么具有整合到染色体中的质粒序列，这表明这些分子对病原体生物学至关重要。有趣的是，我们已经鉴定出6个由伯纳氏c质粒基因编码的Dot/Icm底物，它们被称为Coxiella质粒效应物A - F （CpeA - F）。其中三种蛋白在所有分离株中都是保守的，另外三种蛋白对人类急性疾病分离株的QpH1质粒是特异性的。Aim 1旨在分别表征保守的CpeB和CpeD与自噬体和分泌细胞器的相互作用。目标2将确定感染期间所有六种质粒效应物的需求。此外，本研究目的将确定效应结合宿主蛋白，并确定这些成分对伯氏梭菌感染的需求。目的3将确定在细胞培养和Q热的豚鼠感染模型中伯纳氏梭菌质粒对病原体毒力的要求。总的来说，当前应用的目的将为伯氏梭菌有效寄生宿主细胞的机制提供必要的见解。这些研究也将为伯氏梭菌隐质粒在病原体毒力中的作用提供新的信息。