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.

Neoformans的加密局球会导致致命的加密型脑膜脑炎，并负责15％ 艾滋病患者死亡。这种真菌还会导致个体脑膜脑炎，没有明显的 免疫缺陷和此类事件正在增加。当前抗真菌治疗的结果 隐球菌脑膜脑炎患者远非可接受，死亡率从10到 70％。治疗这种疾病的挑战激发了我们了解隐球菌发病机理和 确定塑造该病原体与哺乳动物宿主之间相互作用的隐球菌因子。我们的 中心前提是，调节宿主反应或神经性的隐球菌因素可以提供目标 用于抗真菌治疗，诊断或预防。 在各种真核病原体中，糖基磷脂酰肌醇（GPI）修饰的糖蛋白是 调节主机响应的杰出参与者。这些糖蛋白对宿主的影响可能具有保护性 或有害。在Neoformans中，甘露蛋白被认为是由 宿主抗晶体细胞介导的免疫反应。但是，只有几种GPI锚定的甘露蛋白 已经在该病原体中研究了，包括毒力因子几丁质脱乙酰基酶CDA1-3和磷脂酶 PLB1。我们以前发现，过表达抗病毒转录因子Znf2 CAN 赋予对宿主的罕见绝育免疫，以通过以后的致命野生型挑战 拉紧。值得注意的是，在49个预测的GPI锚定甘露蛋白基因中，有25个。 Neoformans H99受ZnF2的调节，其中10个被上调，15个下调。这表示 ZnF2在控制这种真菌中控制甘露蛋白表现方面的重要性。最近的一项研究表明13 甘露蛋白基因在隐球菌期间在小鼠和猴子的肺中高度差异表达 感染。鉴于GPI锚定的甘露蛋白是细胞壁蛋白的主要类别，它们也是 我们假设这些蛋白质是最多的，我们假设胶囊的成分是 重要因素组调节与宿主的加密局相互作用。 在这里，我们将系统地检查这49个GPI锚定甘露蛋白在调节中的作用 加密赛宿主相互作用。为了实现这一目标，我们建议完成基因缺失和基因 GPI锚定的甘露蛋白的过表达库。我们将使用这些突变体来定义 这些甘露蛋白与宿主的隐孢子菌病模型中的宿主相互作用。成功的 拟议工作的完成将揭示我们将来可以利用的隐球菌因素或 其他研究宿主免疫，抗真菌靶标或诊断标记。探索性质 拟议的工作及其对我们对宿主之间相互作用的理解产生的潜在影响 这种致命的真菌非常适合R21机制。