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）：Coxiella burnetii是一种细胞内细菌病原体，是人类Q Fever的病因，这是一种急性衰弱的流感样疾病，可以发展为慢性心内膜炎。自从其70年前的发现以来，病原体用来寄生宿主细胞的机制仍然很少了解。在感染过程中，伯内特（C. burnetii）积极调节多个宿主过程，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，但可能通过DOT/ICM IV型分泌系统将其传递到宿主细胞质。当前的应用旨在在功能上表征C. burnetii质粒编码的点/ICM底物并定义其在毒力中的作用。所有的C. burnetii分离株都具有大型隐质质粒，或者将质粒序列整合到其染色体中，这表明这些分子对于病原体生物学至关重要。有趣的是，我们已经确定了六个DOT/ICM底物，该底物由C. burnetii质粒基因编码，这些基因称为Coxiella质粒效应子A -F（CPEA -F）。这些蛋白中的三种在所有分离株中均保守，三个蛋白质特异于人类急性疾病分离株的Qph1质粒。 AIM 1旨在表征保守的CPEB和CPED与自噬体和分泌细胞器的相互作用。 AIM 2将在感染过程中定义所有六个质粒效应子的要求。此外，此目标将识别效应子结合宿主蛋白，并确定这些成分对伯氏梭菌感染的需求。 AIM 3将确定C. burnetii质粒对细胞培养和Q热的豚鼠感染模型中病原体毒力的需求。总体而言，当前应用中的目的将提供所需的洞察力，以了解C. burnetii用来有效地寄生宿主细胞的机制。这些研究还将提供有关C. burnetii隐性质粒在病原体毒力中的作用的新颖信息。 公共卫生相关性：Coxiella burnetii是一种细胞内细菌病原体，会导致人动物病Q热，这是一种使人衰弱的急性疾病，也表现为慢性心内膜炎。目前，伯内特氏梭菌的毒力决定因素知之甚少。通过DOT/ICM IV型分泌系统传递给宿主细胞质的弯曲梭菌蛋白的表征将提供候选治疗靶标，以打击Q发烧，并将为C. burnetii及其宿主之间的相互作用提供所需的见解。拟议的研究的目标是1）表征伯牛梭菌质粒编码的DOT/ICM底物与宿主蛋白的相互作用； 2）确定质粒在病原体毒力中的作用。