Neutral lipid metabolism during Toxoplasma infection

弓形虫感染期间的中性脂质代谢

• 批准号: 9618357
• 负责人: Isabelle Coppens
• 金额: $ 40.93万
• 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/9618357
• 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.

概括 弓形虫Gondii是一种机会性的原生动物寄生虫，对艾滋病/HIV患者构成了重大风险。 目前对弓形虫病的治疗对长期gondii的长寿阶段无效。那， 基于新药的识别，需要长期提供新药物的恒定水流 防止囊肿重新激活。弓形虫是一种义务的细胞内寄生虫，在 在寄生虫液泡中哺乳动物细胞的细胞质，该嗜寄生液泡不与任何宿主细胞器融合。 分化的寄生虫成囊肿形式（Bradyzoites）被哺乳动物内的厚囊肿壁包围 细胞。这些寄生虫如何从宿主细胞中获取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通过复制速二鼠开发的机制以获取脂质 是通过募集和隔离宿主营养填充的细胞器中的寄生虫真空吸尘器。 例如，这些寄生虫从宿主内吞细胞器和高尔基体中检索胆固醇和鞘脂 分别将蔬菜派生到真空中。我们提供了新的证据表明囊肿也形成 打捞胆固醇。存在于所有哺乳动物细胞中，脂质液滴代表了中性的机会来源 脂质清除剂（例如弓形虫）的脂质。我们表明tachyzoites和bradyzoites都依赖于主机 脂质液滴体外生长和动物感染。外源在培养基中添加脂肪酸 刺激速氮和曲二核中的脂质液滴生物发生，表明这些寄生虫能够 清除脂肪酸，用于酯化中性脂质以储存在自己的LD中。总体目标 我们的建议是阐明宿主中性脂质吸收和储存量的机制 通过鉴定这些途径涉及的寄生虫作用来识别Bradyzoites。特定目标1将识别寄生虫 与宿主脂质液滴识别和隔离到寄生虫液泡中有关的效应子。具体的 AIM 2将研究胆二核的胆固醇来源和合成酶的重要性 慢性感染的中性脂质。具体目标3将研究该的内容和生物学特性 速氮和Bradyzoites中的脂质液滴。我们打算为治疗干预开放新的途径 基于限制寄生虫对主要宿主脂质源的访问，并阻止脂质存储路径 弓形虫。