Regulation of Macrophage Cell Death by Toxoplasma gondii

弓形虫对巨噬细胞死亡的调节

• 批准号: 7316867
• 负责人: Amos Z Orlofsky
• 金额: $ 38.83万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-15 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7316867
• 关键词: 9-deoxy-delta-9-prostaglandin D2; Acquired Immunodeficiency Syndrome; Acute; Address; Adenosine Diphosphate Ribose; Adoptive Transfer; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Apoptosis; Apoptotic; Automobile Driving; Biological Assay; Caspase Inhibitor; Cell Death; Cell Line; Cell Survival; Cells; Cessation of life; Chronic Disease; Cyclic AMP; Cytolysis; Cytotoxic T-Lymphocytes; DNA Damage; Elements; Family member; Flow Cytometry; Freezing; Gene Targeting; Green Fluorescent Proteins; Growth; Heat shock proteins; Host Defense; Immigration; Immune response; In Vitro; Incubators; Inflammation; Inflammatory; Inflammatory Response; Inhibition of Apoptosis; Invaded; Link; MAPK8 gene; Mediating; Membrane Potentials; Metabolism; Mitochondria; Modeling; Mus; NF-kappa B; Necrosis; Nitrogen; Opportunistic Infections; Oxygen; Parasites; Pathogenesis; Pathway interactions; Patients; Peroxonitrite; Phagocytosis; Pharmaceutical Preparations; Physiological; Polymerase; Polymerase Chain Reaction; Prevention; Process; Production; Prostaglandins; Prostaglandins E; Protein Overexpression; Publishing; Reactive Oxygen Species; Regulation; Signal Transduction; Signal Transduction Pathway; Stimulus; Testing; Toxoplasma gondii; Toxoplasmosis; Up-Regulation; Vacuole; base; cell type; cyclooxygenase 2; design; in vivo; in vivo Model; inhibitor/antagonist; insight; macrophage; mouse model; novel; parasite invasion; pathogen; prevent; programs; response; stem; tool

DESCRIPTION (provided by applicant): Toxoplasmosis is an important opportunistic infection in AIDS patients. A key feature of T. gondii pathogenesis is the ability of the tachyzoite form of the parasite to use the host cells it invades as incubators for proliferation. Recently an important aspect of this incubation program has emerged for several protozoan pathogens, including T. gondii: the ability of the parasite to promote host cell survival (inhibition of apoptosis). It is unknown how the parasite prevents host cell death. In host macrophages, the problem is compounded by the fact that T. gondii invasion takes place without activation of the anti-apoptotic NF-kB pathway that is normally stimulated by exposure of this cell type to pathogens. Three questions need to be addressed: Is there an in vivo death pathway, generated by host defense, whose initiation or execution is prevented by the intracellular parasite? What is the mechanism by which death is prevented? Finally, how does the parasite benefit from this process? The long-term objectives of this study are to answer these three questions. T. gondii-inhibited apoptosis has been described in vitro using parasitized cell lines and exogenous apoptotic stimuli. Results presented here show in vivo that parasitized macrophages are preferentially spared from apoptosis in a mouse model of acute toxoplasmosis, indicating that the parasite-mediated protection is a naturally occurring pathophysiologic mechanism. This study will develop a convergence between this in vivo model and mechanistic analysis of T. gondii-regulated apoptosis in cultured macrophages. Specific components of the host animal inflammatory response will be manipulated using inhibitors and gene-targeted mice to assess the initiating factors for macrophage apoptosis that is susceptible to parasite regulation. Expression and blockade of apoptotic regulators will be studied in vitro and in vivo to determine the mechanism of parasite-mediated protection. Adoptive transfer assays will be used to link the in vitro and in vivo studies. Finally cytotoxic T lymphocytes will be exploited as a tool to distinguish parasite-regulated apoptosis from parasite-regulated death per se with respect to effects on T. gondii expansion in vivo.

描述（由申请人提供）：弓形虫病是艾滋病患者的重要机会感染。 T. gondii发病机理的一个关键特征是寄生虫的tachyzoite形式使用其侵入宿主细胞作为增殖的孵化器的能力。最近，该孵育程序的一个重要方面已经针对多种原生动物病原体出现，其中包括T. gondii：寄生虫促进宿主细胞存活的能力（抑制细胞凋亡）。未知寄生虫如何阻止宿主细胞死亡。在宿主巨噬细胞中，问题是，弓形虫侵袭发生的事实使问题更加复杂，而没有激活抗凋亡的NF-KB途径，而抗凋亡的NF-KB途径通常会因这种细胞类型暴露于病原体而受到刺激。需要解决三个问题：是否存在由宿主防御产生的体内死亡途径，其启动或处决是由细胞内寄生虫阻止的？防止死亡的机制是什么？最后，寄生虫如何从这个过程中受益？这项研究的长期目标是回答这三个问题。使用寄生的细胞系和外源凋亡刺激在体外描述了Gondii抑制的细胞凋亡。此处介绍的结果表明，体内表明，寄生的巨噬细胞在急性弓形虫病的小鼠模型中优先幸免于凋亡，这表明寄生虫介导的保护是一种天然存在的病理生理机制。这项研究将在该体内模型与培养巨噬细胞中gondii受调节的细胞凋亡的机理分析之间发展。将使用抑制剂和靶向基因的小鼠操纵宿主动物炎症反应的特定成分，以评估容易受到寄生虫调节的巨噬细胞凋亡的起始因子。将在体外和体内研究凋亡调节剂的表达和阻断，以确定寄生虫介导的保护的机理。收养转移测定法将用于将体外和体内研究联系起来。最后，将细胞毒性T淋巴细胞被用作区分寄生虫调节的细胞凋亡与寄生虫调节的死亡本身，就对体内的T. gondii膨胀的影响而言。