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

基本信息

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
项目类别：
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

项目摘要

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.

新型隐球菌可引起致命的隐球菌性脑膜脑炎，并导致 15% 艾滋病患者的死亡。这种真菌也会在没有明显症状的个体中引起脑膜脑炎免疫缺陷和此类事件的发生率正在增加。目前抗真菌治疗的结果隐球菌性脑膜脑炎患者的死亡率远不可接受，死亡率为 10 至 70%。治疗这种疾病的挑战促使我们了解隐球菌的发病机制并确定影响该病原体与哺乳动物宿主之间相互作用的隐球菌因素。我们的中心前提是调节宿主反应或向神经性的隐球菌因子可以提供目标用于抗真菌治疗、诊断或预防。各种真核病原体中的糖基磷脂酰肌醇 (GPI) 修饰的糖蛋白是在调节宿主反应方面发挥着重要作用。这些糖蛋白对宿主的作用可以是保护性的或有害。在新型隐球菌中，甘露糖蛋白被认为是被隐球菌识别的主要成分。宿主抗隐球菌细胞介导的免疫反应。然而，只有几种 GPI 锚定的甘露糖蛋白已对该病原体进行了研究，包括毒力因子几丁质脱乙酰酶 Cda1-3 和磷脂酶 PLB1。我们之前发现过表达抗毒力转录因子 Znf2 的隐球菌细胞可以赋予宿主罕见的绝育免疫力，以应对随后致命的野生型的挑战拉紧。值得注意的是，在 C. 基因组中预测的 49 个 GPI 锚定甘露糖蛋白基因中有 25 个。新型隐球菌 H99 受 Znf2 调节，其中 10 个上调，15 个下调。这表明 Znf2 在控制这种真菌中甘露糖蛋白表达方面的重要性。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在小鼠和猴子的肺部中表达高度差异感染。鉴于 GPI 锚定甘露糖蛋白是细胞壁蛋白的主要类别，并且它们也是新型隐球菌的荚膜成分中，我们假设这些蛋白质代表了最重要的蛋白质之一调节隐球菌与宿主相互作用的重要因素。在这里，我们将系统地研究这 49 种 GPI 锚定的甘露糖蛋白在调节中的作用。隐球菌-宿主相互作用。为了实现这个目标，我们建议完成一个基因缺失和基因 GPI 锚定甘露糖蛋白的过表达文库。我们将使用这些突变体来定义在隐球菌病动物模型中，这些甘露糖蛋白与隐球菌与宿主相互作用。成功的完成拟议的工作将揭示我们将来可以利用的隐球菌因素或其他用于研究宿主免疫、抗真菌靶点或诊断标记。探索性的本质拟议的工作及其对我们理解主办方和主办方之间互动的潜在影响这种致命的真菌非常适合 R21 机制。