Novel rhoptry effector proteins in Toxoplasma host-pathogen interaction

弓形虫宿主-病原体相互作用中的新型棒状体效应蛋白

• 批准号: 8229898
• 负责人: Peter John Bradley
• 金额: $ 23.1万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-15 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8229898
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Address; Affinity; Ala-Trp-Arg-His-Pro-Gln-Phe-Gly-Gly; Blood; Cell physiology; Cells; Central Nervous System Diseases; Chronic; Complex; Congenital Abnormality; Cytoplasm; Cytoplasmic Granules; Cytosol; Destinations; Disease; Family; Genes; Hand; Human; Immune response; Immunocompromised Host; In Vitro; Individual; Infection; Injection of therapeutic agent; Invaded; Knock-out; Mammalian Cell; Masks; Mediating; Microarray Analysis; Monoclonal Antibodies; Mus; Names; Needles; Nomenclature; Organelles; Organism; Parasites; Pathway interactions; Patients; Penetration; Phenotype; Phosphotransferases; Play; Population; Positioning Attribute; Process; Proteins; Proteomics; Role; Series; Shapes; Signal Pathway; Staging; System; Toxoplasma; Toxoplasma gondii; Virulence; Work; experience; in vivo; insight; knockout gene; neonate; novel; obligate intracellular parasite; pathogen; protein function; response; rhoptry; success; tissue tropism; tool; trafficking

DESCRIPTION (provided by applicant): Toxoplasma gondii is an obligate intracellular parasite that causes severe central nervous system disorders in immunocompromised individuals and birth defects in congenitally infected neonates. Intracellular survival of these organisms is dependent on the ability to invade their host cell, establish a replication-permissive niche, and avoid host cell defenses. The secretory rhoptries have emerged as a key organelle that regulates both invasion and hijacking of host cell functions. For hijacking host functions, the rhoptries inject a burst of proteins into the host cell cytoplasm that can be trafficked to distinct compartments within the infected cell and directly target host pathways. The importance of these host "effector" proteins is exemplified by a family of rhoptry kinases that are injected and play critical roles in modulating host signaling pathways and regulating parasite virulence. In addition to ROP kinases, the rhoptries inject an array of other effector proteins that are of unknown function. Most of these proteins lack homology to known proteins or identifiable domains and are unique to Toxoplasma and closely related parasites. We have identified a panel of these novel rhoptry effectors and developed gene knockouts in the biologically relevant type II strain parasites for their study. In this proposal, we will determine the role of these novel effector proteins in regulating host functions. Specifically, we will determine the host response to ?effector strains in vitro using host microarray analysis and in vivo by assessing virulence, tissue tropism, and bradyzoite formation in mice. We will additionally use exogenous expression of tandem affinity tagged effector proteins in host cells to determine their destination and identify host targets. Together, these complementary approaches promise to reveal novel mechanistic insights into how Toxoplasma uses this unique set of effector proteins to modulate its mammalian host cell. PUBLIC HEALTH RELEVANCE: Toxoplasma gondii is an intracellular parasite that infects up to a third of the world's human population and causes serious disease in immunocompromised (AIDS) patients and congenitally-infected neonates. Toxoplasma secretes an array of factors from an organelle named the rhoptries that enable it to invade and hijack its host cell. This project is focused determining the function of a novel group of rhoptry effector proteins by examining the host response to gene knockout parasites and identifying host proteins that interact with these novel effectors.

描述(申请人提供)：弓形虫是一种专性细胞内寄生虫，可在免疫功能受损的个体中引起严重的中枢神经系统疾病，并在先天性感染的新生儿中引起出生缺陷。这些生物的细胞内生存取决于入侵它们的宿主细胞、建立允许复制的生态位和避免宿主细胞防御的能力。分泌杆状病毒已成为调节宿主细胞入侵和劫持功能的关键细胞器。为了劫持宿主功能，棒状病毒向宿主细胞细胞质注入一系列蛋白质，这些蛋白质可以被运输到受感染细胞内的不同隔室，并直接针对宿主途径。这些宿主“效应器”蛋白的重要性被注射的一系列棒状蛋白所证明，这些蛋白在调节宿主信号通路和调节寄生虫毒力方面发挥关键作用。除了ROP激酶，棒状病毒还会注入一系列其他功能未知的效应器蛋白。这些蛋白大多缺乏与已知蛋白或可识别结构域的同源性，是弓形虫和密切相关寄生虫所特有的。我们已经确定了一组新的棒状病毒效应器，并在生物学上相关的II型寄生虫中开发了基因敲除，用于他们的研究。在这项提案中，我们将确定这些新的效应蛋白在调节宿主功能中的作用。具体地说，我们将在体外使用宿主微阵列分析来确定宿主对效应菌株的反应，并在体内通过评估小鼠的毒力、组织嗜性和缓殖体形成来确定宿主的反应。此外，我们还将在宿主细胞中使用串联亲和标记效应器蛋白的外源表达来确定它们的目的地和识别宿主靶标。总之，这些互补的方法有望揭示弓形虫如何利用这组独特的效应蛋白来调节其哺乳动物宿主细胞的新的机制洞察力。 与公共卫生相关：弓形虫是一种细胞内寄生虫，感染多达三分之一的世界人口，并在免疫功能低下(艾滋病)患者和先天性感染的新生儿中导致严重疾病。弓形虫分泌一系列来自细胞器的因子，这种细胞器被称为棒状病毒，使其能够入侵和劫持宿主细胞。该项目的重点是通过检测宿主对基因敲除寄生虫的反应来确定一组新的杆状病毒效应器蛋白的功能，并确定与这些新效应器相互作用的宿主蛋白。