Host factors required for Leishmania infection

利什曼原虫感染所需的宿主因素

• 批准号: 8639242
• 负责人: Neal Silverman
• 金额: $ 25.05万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8639242
• 关键词: Adult; Affect; Animals; Apoptotic; Bacteria; Binding; Biological; Biological Models; Bite; Bone Marrow; CD36 gene; Cell Line; Cells; Communicable Diseases; Cytolysis; Defect; Drosophila genus; Future; Genes; Genetic; Homologous Gene; Human; Immune; Immune response; Immunologics; Infection; Integral Membrane Protein; Integration Host Factors; Knockout Mice; Lead; Leishmania; Leishmaniasis; Lesion; Mammals; Mediating; Modeling; Molecular; Morbidity - disease rate; Mouse Strains; Mus; Parasites; Parasitic infection; Phagocytosis; Phenotype; Play; Process; Proteins; Prunella vulgaris; RNA Interference; Role; Sand Flies; Signal Transduction; Small Interfering RNA; Study models; Tropical Disease; Vacuole; Wild Type Mouse; base; cell injury; fly; foot; genome-wide; in vivo; insight; macrophage; mortality; mouse model; neglect; novel; public health relevance; receptor; scavenger receptor; tool; trafficking

DESCRIPTION (provided by applicant): Leishmaniasis is a neglected tropical disease, vectored by sand flies and caused by the protozoan parasites of the Leishmania genus, that affects 12 million people globally. Drosophila models for the study of host-Leishmania interactions have been developed, and it is proposed to exploit the unique and powerful genetic tools available in this model system to discover novel and conserved factors required for the phagocytosis and/or intracellular survival of Leishmania parasites. In fact, CD36-like scavenger receptors have been identified as critical components of anti-parasitic defenses in Drosophila. Extending this discovery to mice, CD36 deficiency was found to cause enlarged and persistent foot pad lesions following Leishmania infection, and ex vivo CD36-deficient macrophages present markedly reduced parasitophorous vacuoles. These phenotypes demonstrate that the CD36 scavenger receptor plays a crucial role in L. amazonensis infection, which will be further characterized in Aim 1. Using a Drosophila cellbased model, a genome-wide RNAi screen to identify genes involved in the phagocytosis of L.amazonensis amastigotes was also performed. This screen identified 52 highly conserved genes required for the phagocytosis of Leishmania, but not involved in phagocytosis of bacteria. One candidate is the transmembrane protein Draper, a scavenger receptor best known for its role in recognizing and clearing apoptotic or damaged cells, suggesting it also functions in parasite recognition (Aim 2). It is not yet known if the other candidates are involved in parasite recognition, intracellular trafficking or other aspecs of parasite phagocytosis/invasion. In order to focus on the most promising candidates for study in mammals, Aim 3 will characterize the function of these other factors in the phagocytosis of Leishmania in mammalian macrophage cell lines.

描述（由申请人提供）：利什曼病是一种被忽视的热带疾病，由白蛉传播，由利什曼原虫属原生动物寄生虫引起，影响全球 1200 万人。用于研究宿主与利什曼原虫相互作用的果蝇模型已经开发出来，并建议利用该模型系统中可用的独特且强大的遗传工具来发现利什曼原虫吞噬作用和/或细胞内存活所需的新颖且保守的因子。事实上，CD36 样清道夫受体已被确定为果蝇抗寄生虫防御的关键组成部分。将这一发现扩展到小鼠身上，发现 CD36 缺陷会导致利什曼原虫感染后足垫病变扩大且持续，并且离体 CD36 缺陷型巨噬细胞呈现出明显减少的寄生空泡。这些表型表明 CD36 清道夫受体在亚马逊乳杆菌感染中发挥着至关重要的作用，这将在目标 1 中进一步表征。还使用果蝇细胞模型进行了全基因组 RNAi 筛选，以鉴定参与亚马逊乳杆菌无鞭毛体吞噬作用的基因。该筛选鉴定了利什曼原虫吞噬作用所需的 52 个高度保守的基因，但不参与细菌的吞噬作用。其中一个候选者是跨膜蛋白 Draper，这是一种清道夫受体，以其在识别和清除凋亡或受损细胞中的作用而闻名，这表明它也在寄生虫识别中发挥作用（目标 2）。目前尚不清楚是否 其他候选者参与寄生虫识别、细胞内运输或寄生虫吞噬/入侵的其他方面。为了重点关注最有希望在哺乳动物中进行研究的候选因子，Aim 3 将表征这些其他因子在哺乳动物巨噬细胞系中利什曼原虫吞噬作用中的功能。