Host Factors in Cryptococcal Infection

隐球菌感染的宿主因素

• 批准号: 8457528
• 负责人: Deepa Latha Srikanta
• 金额: $ 5.39万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8457528
• 关键词: Adherence; Affect; Biological; Biological Assay; Blood - brain barrier anatomy; Blood Circulation; Brain; Breathing; Cell Line; Cell secretion; Cells; Cessation of life; Characteristics; Contracts; Cryptococcus; Cryptococcus neoformans; Cryptococcus neoformans infection; Cytolysis; Disease; Event; Gene Expression; Genes; HIV Seropositivity; Health Services Accessibility; Human; Image; Immunocompromised Host; In Vitro; Individual; Infection; Integration Host Factors; Latex Bead; Libraries; Life; Lung; Melanins; Meningitis; Modeling; Molecular; Mus; Mutant Strains Mice; Organism; Pathogenesis; Phagocytes; Phagocytosis; Phosphoric Monoester Hydrolases; Phosphotransferases; Pigments; Play; Polysaccharides; Prevalence; Prevention; Prevention strategy; Process; Processed Genes; Proteins; RNA Interference; Research; Role; Saccharomyces cerevisiae; Small Interfering RNA; Testing; Therapeutic Intervention; Virulence Factors; Work; Yeasts; base; capsule; cell type; design; falls; fighting; in vitro Model; interest; macrophage; mouse model; particle; pathogen; public health relevance; research study; therapeutic development; uptake

DESCRIPTION (provided by applicant): Cryptococcus neoformans is a fungal pathogen that causes serious disease in immunocompromised patients and results in an annual death toll of over 600,000. Cryptococcosis is contracted by inhalation of the infectious particle, which leads to a primary pulmonary infection. C. neoformans is a facultative intracellular pathogen. After initial engulfment by phagocytic cells in the lungs it may lyse or exit these cells and disseminate throughout the mammalian host, either in the bloodstream or by entering additional phagocytes. The consequence of dissemination to the brain is lethal meningitis. Several C. neoformans virulence factors have been implicated in the pathogenesis of this disease, including formation of the protective pigment melanin, the presence on fungal cells of an extensive polysaccharide capsule, and secretion of certain proteins. Host factors also play a role in infection, and host phagocytes have been implicated in pathogen latency and dissemination. Despite the demonstration of host phagocytic cell involvement in this disease, there has been no effort to systematically identify and study genes that are significant for the infection process. In preliminary studies, I developed and optimized a high-throughput imaging assay to efficiently evaluate the interactions between C. neoformans and RNAi-treated human macrophage-like cell lines. I then screened a subset of host genes to identify factors important in these interactions, by using commercially available siRNA libraries to down-regulate expression of genes encoding 901 human kinases and phosphatases in the host cells and then performing interaction assays. This screen identified 8 genes as having specific roles in host:fungal interactions; in this application I propose to study two of them in detail. The broad, long-term objectives of this project are to identify host genes that play a significant role in fungal pathogenesis and to discover their mechanisms of involvement. Aim 1 is designed to test the roles of two candidate host genes in models relevant to pathogenesis, including mouse primary cells in vitro and models of infection. Aim 2 is designed to elucidate the cellular mechanisms by which the products of the two host genes of interest influence host:fungal interactions. These studies will elucidate key aspects of pathogenesis of this important disease by defining how specific host factors affect the interaction of phagocytic cells with C. neoformans. This work will increase understanding of cryptococcosis and potentially aid in the development of therapeutic or preventive strategies to fight this disease.

描述（由申请人提供）：新型隐球菌是一种真菌病原体，可引起免疫功能低下患者的严重疾病，并导致每年超过 600,000 人死亡。隐球菌病是通过吸入传染性颗粒而感染的，从而导致原发性肺部感染。新型隐球菌是一种兼性细胞内病原体。在最初被肺部吞噬细胞吞噬后，它可能会裂解或退出这些细胞并传播 整个哺乳动物宿主，无论是在血流中还是通过进入额外的吞噬细胞。传播到大脑的后果是致命的脑膜炎。多种新型隐球菌毒力因子与该疾病的发病机制有关，包括保护性黑色素的形成、真菌细胞上广泛多糖荚膜的存在以及某些蛋白质的分泌。宿主因素也在感染中发挥作用，宿主吞噬细胞与病原体的潜伏和传播有关。尽管已证明宿主吞噬细胞参与了这种疾病，但尚未系统地识别和研究对感染过程具有重要意义的基因。在初步研究中，我开发并优化了一种高通量成像测定法，以有效评估新型隐球菌和 RNAi 处理的人类巨噬细胞样细胞系之间的相互作用。然后，我通过使用市售 siRNA 文库来下调宿主细胞中编码 901 种人类激酶和磷酸酶的基因的表达，然后进行相互作用测定，筛选了宿主基因的子集，以确定这些相互作用中重要的因素。该筛选确定了 8 个在宿主：真菌相互作用中具有特定作用的基因；在这个应用程序中，我建议详细研究其中两个。该项目的广泛、长期目标是确定在真菌发病机制中发挥重要作用的宿主基因并发现其参与机制。目标 1 旨在测试两个候选宿主基因在与发病机制相关的模型中的作用，包括体外小鼠原代细胞和感染模型。目标 2 旨在阐明两个感兴趣的宿主基因的产物影响宿主：真菌相互作用的细胞机制。这些研究将通过定义特定宿主因素如何影响吞噬细胞与新型隐球菌的相互作用来阐明这种重要疾病发病机制的关键方面。这项工作将增加对隐球菌病的了解，并可能有助于制定对抗这种疾病的治疗或预防策略。