Defining the genetic network governing cryptococcal morphological transition

定义控制隐球菌形态转变的遗传网络

• 批准号: 9923532
• 负责人: Xiaorong Lin
• 金额: $ 47.18万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-11 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923532
• 关键词: Acquired Immunodeficiency Syndrome; Antifungal Agents; Attenuated; Biological Assay; Candida albicans; Candidate Disease Gene; Cell Nucleus; Cells; Central Nervous System Diseases; Cessation of life; Clinical; Complex; Cryptococcal Meningitis; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Development; Disease; Filament; Future; Gene Deletion; Genetic; Genetic Epistasis; Genetic Screening; Goals; Immune; Immune response; Immunity; Immunization; In Vitro; Induced Mutation; Infection; Insertional Mutagenesis; Link; Measures; Modeling; Molecular; Morphogenesis; Morphology; Mutation; Nuclear; Nuclear Translocation; Partner in relationship; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Pattern; Phenotype; Pheromone; Phosphotransferases; Play; Proteins; Public Health; Refractory; Regulation; Research; Role; Serotyping; Signal Pathway; Stimulus; Testing; Vaccines; Virulence; Virulent; Work; Yeasts; Zinc Fingers; base; design; fungus; genetic linkage; genome sequencing; in vivo; mortality; mutant; novel therapeutics; overexpression; pathogen; prevent; programs; protein expression; response; transcription factor

Abstract Cryptococcal meningitis is an AIDS-defining condition and it is responsible for 15% of the deaths in AIDS patients. The disease has mortality rates up to 70% and it claims hundreds of thousands of lives each year. The existing antifungal drugs are not always effective and there is no vaccine available against cryptococcosis. The challenges of preventing and treating this disease motivate us to investigate cryptococcal pathogenesis and identify cryptococcal pathways that can induce a protective host response. Cryptococcus neoformans can undergo yeast-to-filament morphological transition. We and others have shown that morphotype has a profound effect on cryptococcal interaction with various hosts. In mammalian models of cryptococcosis, the yeast form is pathogenic while the filamentous form is attenuated/abolished in virulence. Previously, we identified a key regulator of filamentation, Znf2. Deletion of ZNF2 locks cells in the yeast form and enhances virulence. Overexpression of ZNF2 promotes filamentation in vitro and in vivo, abolishes virulence, and can offer rare sterilizing immunity against an otherwise lethal challenge. Based on these studies, we hypothesize that activating the cryptococcal filamentation program can elicit protective host responses and alleviate cryptococcosis. The goal of this application is to characterize filamentation pathways and identify those that induce protective host responses and attenuate cryptococcal virulence. Capitalizing on our recent discoveries of self-filamentation in natural isolates of C. neoformans species complex (serotype A and D), we performed multiple large genetic screens and identified candidate genes that play important roles in filamentation in vitro. Among these candidates, multiple components of the osmotic sensing pathway suppress filamentation in the serotype A reference strain H99 by inhibiting nuclear translocation of the transcription factor Crz1, which acts upstream of Znf2. In Aim 1, we will define the mechanism by which Crz1 distinguishes different stimuli to activate filamentation. In Aim 2, we will characterize the identified candidates and establish their genetic relationship with Znf2 in controlling cryptococcal virulence and morphology in vivo. In Aim 3, we will test the avirulent strains for their immunization effect and their combined effect with Znf2 on host immunity. The work will generate a set of Cryptococcus morphological mutants that induce protective host responses. These findings will reveal targets that can be exploited in the future by us and others to investigate new measures against this deadly fungal disease.

摘要 隐球菌性脑膜炎是一种艾滋病的定义条件，它是负责15%的死亡， 艾滋病患者。这种疾病的死亡率高达70%，每种疾病都夺去数十万人的生命。 年现有的抗真菌药物并不总是有效的，也没有疫苗可用于预防 隐球菌病预防和治疗这种疾病的挑战促使我们研究隐球菌 致病机制和鉴定隐球菌途径，可以诱导保护性宿主反应。 新型隐球菌可以经历酵母到丝状形态的转变。我们和其他人已经 表明形态型对隐球菌与各种宿主的相互作用具有深远的影响。在哺乳动物 在隐球菌病的模型中，酵母形式是致病性的，而丝状形式在隐球菌病中被减弱/消除。 毒力。以前，我们确定了一个关键的调节剂，Znf 2。ZNF 2的缺失将细胞锁定在 酵母形成并增强毒力。ZNF 2的过表达促进体外和体内的表达， 消除了毒力，并能提供罕见的杀菌免疫力，以对抗其他致命的挑战。基于 这些研究中，我们假设激活隐球菌表达程序可以诱导保护性宿主 缓解隐球菌病。此应用程序的目标是表征 途径，并确定那些诱导保护性宿主反应和减弱隐球菌 毒性 利用我们最近在自然分离的C.新形种 复杂（血清型A和D），我们进行了多次大的遗传筛选，并确定了候选基因， 在体外表达中起重要作用。在这些候选者中，渗透压的多个组分 传感途径通过抑制核内信号转导抑制血清型A参考菌株H99的表达 转录因子Crz 1的易位，其作用于Znf 2的上游。在目标1中，我们将定义 Crz 1区分不同刺激以激活定向的机制。在目标2中，我们将 鉴定鉴定的候选物，并建立它们与Znf 2的遗传关系， 体内隐球菌毒力和形态学。在目标3中，我们将测试无毒菌株的免疫力 影响及其与Znf 2对宿主免疫的联合作用。这项工作将产生一套隐球菌 诱导保护性宿主反应的形态学突变体。这些发现将揭示可以被 我们和其他人将在未来利用这些技术来研究对抗这种致命真菌疾病的新措施。