Systematic investigation of GPI-anchored mannoproteins in Cryptococcus neoformans

新型隐球菌中 GPI 锚定甘露糖蛋白的系统研究

• 批准号: 10117186
• 负责人: Xiaorong Lin
• 金额: $ 22.65万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-02 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10117186
• 关键词: Acquired Immunodeficiency Syndrome; Adhesions; Animal Model; Antifungal Agents; Antifungal Therapy; Biological Assay; Brain; Cell Wall; Cell surface; Cells; Cellular Morphology; Cessation of life; Chitin deacetylase; Clinical; Communities; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Data; Development; Diagnosis; Diagnostic; Disease; Exploratory/Developmental Grant; Financial compensation; Future; GPI Membrane Anchors; Gene Deletion; Genes; Genome; Glycoproteins; Glycosylphosphatidylinositols; Goals; Grant; Immune; Immune response; Immunity; Immunoassay; Immunotherapy; In Vitro; Incidence; Individual; Infection; Inhalation; Invaded; Investigation; Ions; Libraries; Lung; Lung infections; Meningoencephalitis; Metals; Modification; Molecular; Monkeys; Mus; Nature; Neurotropism; Outcome; Pathogenesis; Patients; Peptide Signal Sequences; Phagocytosis; Phenotype; Phospholipase; Prevention; Proteins; Public Health; Publications; Regulation; Research; Role; Serology; Shapes; Stress; Surface Properties; Testing; Transcript; Vaccination; Virulence; Virulence Factors; Work; Yeasts; base; capsule; cell mediated immune response; chemotherapy; diagnostic biomarker; differential expression; fungus; in vitro Assay; internal control; loss of function; macrophage; mannoproteins; mortality; mouse model; mutant; novel therapeutics; overexpression; pathogen; pathogenic fungus; prevent; transcription factor; transcriptome sequencing; vaccine candidate

Cryptococcus neoformans causes fatal cryptococcal meningoencephalitis and is responsible for 15% of deaths in AIDS patients. This fungus can also cause meningoencephalitis in individuals without apparent immuno-deficiency and such incidences are increasing. The outcome of the current antifungal therapy for patients with cryptococcal meningoencephalitis is far from acceptable, with mortality rates ranging from 10 to 70%. The challenges of treating this disease motivate us to understand cryptococcal pathogenesis and to identify cryptococcal factors that shape the interactions between this pathogen and a mammalian host. Our central premise is that cryptococcal factors that modulate host response or neurotropism could provide targets for antifungal therapy, diagnosis, or prevention. Glycosylphosphatidylinositol (GPI)-modified glycoproteins in various eukaryotic pathogens are prominent players in modulating host responses. The effect of these glycoproteins to the host can be protective or deleterious. In C. neoformans, mannoproteins are considered the primary components recognized by the host anti-cryptococcal cell-mediated immune response. However, only several GPI-anchored mannoproteins have been studied in this pathogen, including virulence factors chitin deacetylases Cda1-3 and phospholipase Plb1. We previously found that cryptococcal cells overexpressing an anti-virulence transcription factor Znf2 can confer rare sterilizing immunity to the host against a subsequent challenge by an otherwise lethal wild type strain. Remarkably, 25 out of the 49 predicted GPI-anchored mannoprotein genes in the genome of C. neoformans H99 are regulated by Znf2, with 10 being upregulated and 15 downregulated. This indicates the importance of Znf2 in controlling mannoprotein presentation in this fungus. A recent study indicates that 13 mannoprotein genes are highly differentially expressed in lungs of both mice and monkeys during cryptococcal infection. Given that GPI-anchored mannoproteins are the major class of cell wall proteins and they are also components of the capsule in C. neoformans, we hypothesize that these proteins represent one of the most important groups of factors modulating cryptococcal interactions with the host. Here we will systematically examine the role of these 49 GPI-anchored mannoproteins in modulating Cryptococcus-host interactions. To achieve this goal, we propose to complete a gene deletion and gene overexpression library for the GPI-anchored mannoproteins. We will use these mutants to define the roles of these mannoproteins in cryptococcal interaction with the host in an animal model of cryptococcosis. Successful completion of the proposed work will reveal cryptococcal factors that can be exploited in the future by us or others to investigate host immunity, antifungal targets, or diagnostic markers. The exploratory nature of the proposed work and the potential impact it has on our understanding of the interaction between the host and this deadly fungus fits perfectly for the R21 mechanism.

新型隐球菌引起致命的隐球菌脑膜脑炎， 艾滋病患者死亡。这种真菌也可以引起脑膜脑炎的个人没有明显的 免疫缺陷症和这种发病率正在增加。目前抗真菌治疗的结果 隐球菌性脑膜脑炎患者的死亡率从10 - 10%不等， 百分之七十治疗这种疾病的挑战促使我们了解隐球菌的发病机制， 确定隐球菌因子，塑造这种病原体和哺乳动物宿主之间的相互作用。我们 核心前提是调节宿主反应或嗜神经性的隐球菌因子可以提供靶点 用于抗真菌治疗、诊断或预防。 糖基磷脂酰肌醇（GPI）修饰的糖蛋白在各种真核生物病原体， 在调节宿主反应方面的重要角色。这些糖蛋白对宿主具有保护作用 或有害的。In C.甘露糖蛋白被认为是由新变型识别的主要成分。 宿主抗隐球菌细胞介导的免疫应答。然而，只有几个GPI锚定的甘露糖蛋白， 已研究了该病原菌的毒力因子，包括几丁质脱乙酰酶Cda 1 -3和磷脂酶 Plb 1。我们以前发现过表达抗毒性转录因子Znf 2的隐球菌细胞， 赋予宿主罕见的绝育免疫力，以抵抗随后的致命野生型攻击 株值得注意的是，在C. 新生儿H99受Znf 2调节，其中10个上调，15个下调。这表明 Znf 2在控制该真菌中甘露糖蛋白呈递中的重要性。最近的一项研究表明，13 甘露糖蛋白基因在隐球菌感染期间小鼠和猴肺中的表达高度差异 感染鉴于GPI锚定的甘露糖蛋白是细胞壁蛋白的主要类别，并且它们还 C中胶囊的组分。我们假设这些蛋白质代表了 调节隐球菌与宿主相互作用的重要因子群。 在这里，我们将系统地研究这49个GPI锚定的甘露糖蛋白在调节 隐球菌与宿主的相互作用。为了实现这一目标，我们建议完成一个基因的缺失和基因 GPI锚定的甘露糖蛋白的过表达文库。我们将用这些突变体来定义 在隐球菌病的动物模型中，这些甘露糖蛋白与宿主的隐球菌相互作用。成功 完成拟议的工作将揭示隐球菌因子，可以在未来利用我们或 另一些用于研究宿主免疫、抗真菌靶点或诊断标志物。的探索性质 拟议的工作及其对我们理解宿主与宿主之间的相互作用的潜在影响。 这种致命的真菌完全符合R21的机制