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: 9615729
• 负责人: Xiaorong Lin
• 金额: $ 46.24万
• 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/9615729
• 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.

抽象的 隐球菌脑膜炎是一种定义艾滋病的疾病，造成15％的死亡 艾滋病患者。该疾病的死亡率高达70％，并且夺走了数十万生命 年。现有的抗真菌药物并不总是有效的，并且没有可用的疫苗 隐球菌病。预防和治疗这种疾病的挑战激发了我们调查隐球菌 发病机理并识别可以诱导保护性宿主反应的隐球菌途径。 加密赛车可以进行酵母丝形态的形态过渡。我们和其他人有 表明形态型对与各种宿主的隐球菌相互作用具有深远的影响。在哺乳动物 隐球菌病模型，酵母形式是致病性的，而丝状形式被减弱/废除 毒力。以前，我们确定了细丝的关键调节剂Znf2。 ZNF2的删除锁定细胞中的细胞 酵母菌形成并增强毒力。 Znf2的过表达促进体外和体内细丝， 废除毒力，可以为罕见的抗药性提供罕见的抗药性，以防止杀伤性的挑战。基于 这些研究，我们假设激活隐球菌细丝计划可以引起保护宿主 反应并减轻隐球菌病。该应用的目的是表征细丝 途径并确定那些诱导保护性宿主反应并衰减隐球菌的途径 毒力。 利用我们最近在C. neoformans物种的自然分离株中自丝化的发现 复合物（血清型A和D），我们进行了多个大遗传筛选，并确定了候选基因 在体外发挥重要作用。在这些候选人中，渗透的多个组成部分 传感途径通过抑制核能抑制血清型A参考菌株H99 转录因子CRZ1的易位，该因子在Znf2的上游起作用。在AIM 1中，我们将定义 CRZ1区分不同刺激以激活细丝的机制。在AIM 2中，我们将 表征已确定的候选者并在控制中建立其与ZnF2的遗传关系 在体内的隐球菌毒力和形态。在AIM 3中，我们将测试无毒菌株的免疫 效果及其与ZnF2对宿主免疫的效果。这项工作将产生一组加密赛车 诱导保护性宿主反应的形态突变体。这些发现将揭示可能是 将来我们和其他人在未来利用，以调查针对这种致命真菌疾病的新措施。