Neutral lipid metabolism during Toxoplasma infection

弓形虫感染期间的中性脂质代谢

• 批准号: 9914210
• 负责人: Isabelle Coppens
• 金额: $ 40.94万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-04 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9914210
• 关键词: AIDS/HIV problem; Abbreviations; Acquired Immunodeficiency Syndrome; Acyl Coenzyme A; Adverse effects; Animals; Biochemical; Biogenesis; Biological; Biological Assay; Brain; Cells; Cholesterol; Cholesterol Esters; Chorioretinitis; Complement; Cyst; Cytoplasm; Cytosol; Data; Development; Diglycerides; Docking; Drug Targeting; Encephalitis; Enzymes; Fatty Acids; Genetic Screening; Goals; Golgi Apparatus; Growth; HIV; High Prevalence; Immunity; In Vitro; Infection; Intercept; Invaded; Lesion; Light; Lipids; Low-Density Lipoproteins; Mammalian Cell; Mediating; Membrane; Microscopy; Molecular; Morphology; Myocarditis; Neurons; Nutrient; Oleic Acids; Opportunistic Infections; Organelles; Parasites; Pathway interactions; Patients; Phagocytes; Pharmaceutical Preparations; Population; Prevalence; Process; Property; Proteins; Proteomics; Recrudescences; Regimen; Risk; Source; Sphingolipids; Sterol O-Acyltransferase; Stream; Surface; Techniques; Therapeutic Intervention; Thick; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Tumor stage; Vaccines; Vacuole; Vesicle; acute infection; adipocyte differentiation; auxotrophy; base; chronic infection; diacylglycerol O-acyltransferase; lipid metabolism; new therapeutic target; novel therapeutics; obligate intracellular parasite; pandemic disease; pathogen; recruit; toxoplasmic encephalitis; trafficking; uptake

SUMMARY Toxoplasma gondii is an opportunistic protozoan parasite that poses a significant risk to AIDS/HIV patients. Current treatments for toxoplasmosis are ineffective against the long-lived encysted stage of T. gondii. Thus, a constant stream of new drugs based on the identification of novel drug targets is required to offer long-term protection against cyst reactivation. Toxoplasma is an obligate intracellular parasite that multiplies in the cytoplasm of mammalian cells within a parasitophorous vacuole that does not fuse with any host organelles. Differentiated parasites into cyst forms (bradyzoites) are surrounded by a thick cyst wall within mammalian cells. How these parasites acquire their nutrients from the host cell has been an intriguing question in the field. We previously demonstrated that one mechanism developed by replicating tachyzoites to gain access to lipids is through the recruitment and sequestration of host nutrient-filled organelles into the parasitophorous vacuole. For example, these parasites retrieve cholesterol and sphingolipids from host endocytic organelles and Golgi- derived vesicles internalized into the vacuole, respectively. We provide new evidence that the cyst forms also salvage cholesterol. Present in all mammalian cells, lipid droplets represent an opportune source of neutral lipids for a lipid scavenger such as Toxoplasma. We show that both tachyzoites and bradyzoites rely on host lipid droplets for growth in vitro and infectivity in animals. Exogenous addition of fatty acids to the medium stimulate lipid droplet biogenesis in tachyzoites and bradyzoites, indicating that these parasites are capable of scavenging fatty acids that they use to esterify neutral lipids for storage in their own LD. The overall goal of our proposal is to unravel the mechanisms of host neutral lipid uptake and storage in tachyzoites and bradyzoites by identifying parasite effectors involved in these pathways. Specific Aim 1 will identify the parasite effectors involved in host lipid droplet recognition and sequestration into the parasitophorous vacuole. Specific Aim 2 will investigate the source of cholesterol for bradyzoites and the importance of enzymes synthesizing neutral lipids for chronic infection. Specific Aim 3 will investigate the content and biological properties of the lipid droplets in tachyzoites and bradyzoites. We will intend to open new avenues for therapeutic interventions based on restricting the parasite’s access to major host lipid sources and blocking lipid storage pathways in Toxoplasma.

总结 弓形虫是一种机会性原生动物寄生虫，对艾滋病/艾滋病毒患者构成重大风险。 目前的弓形虫病治疗方法对长期存活的包囊期弓形虫是无效的。刚地。因此，本发明的目的是， 需要基于新药物靶点的鉴定的源源不断的新药，以提供长期的 防止囊肿再激活。弓形虫是一种专性细胞内寄生虫， 哺乳动物细胞的细胞质，位于寄生虫的液泡中，不与任何宿主细胞器融合。 在哺乳动物体内，分化为包囊形式（缓殖子）的寄生虫被厚的包囊壁包围。 细胞这些寄生虫如何从宿主细胞中获得营养一直是该领域的一个有趣的问题。 我们以前证明了一种机制是通过复制速殖子来获得脂质 是通过招募和隔离寄主营养填充细胞器进入寄生泡。 例如，这些寄生虫从宿主的内吞细胞器和高尔基体中获取胆固醇和鞘脂， 衍生的小泡分别内化到液泡中。我们提供了新的证据表明囊肿的形成也 挽救胆固醇。存在于所有哺乳动物细胞中，脂滴是中性粒细胞的合适来源。 脂质清除剂如弓形虫。我们发现速殖子和缓殖子都依赖于宿主 脂滴的体外生长和动物感染性。向培养基中外源添加脂肪酸 刺激速殖子和缓殖子中的脂滴生物发生，表明这些寄生虫能够 清除脂肪酸的能力，它们用这些脂肪酸来分解中性脂质，以便储存在自己的LD中。的总目标 我们的建议是解开宿主中性脂质摄取和储存在速殖子中的机制， 通过识别参与这些途径的寄生虫效应子来识别缓殖子。具体目标1将识别寄生虫 参与宿主脂滴识别和隔离进入寄生虫液泡的效应子。具体 目的2探讨缓殖子胆固醇的来源及酶合成的重要性 慢性感染的中性脂质。具体目标3将研究的内容和生物学特性， 速殖子和缓殖子中的脂滴。我们将打算为治疗干预开辟新的途径 基于限制寄生虫进入主要的宿主脂质来源和阻断脂质储存途径， 弓形虫