Mechanism of GPCR Signaling-mediated Fungal Cell Gigantism

GPCR信号介导真菌细胞巨型化的机制

• 批准号: 8765500
• 负责人: Chaoyang Xue
• 金额: $ 25.19万
• 依托单位: RBHS-NEW JERSEY MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8765500
• 关键词: AIDS/HIV problem; Accounting; Age; Alveolar Macrophages; Antifungal Agents; Brain; Cell Line; Cell Size; Cells; Cessation of life; Communicable Diseases; Communication; Cryptococcus; Cryptococcus neoformans; Cryptococcus neoformans infection; Cyclic AMP; Data; Development; Disease; Drug Targeting; Effectiveness; Endothelial Cells; Environment; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP-Binding Proteins; Gigantism; Goals; Human; Immune; In Vitro; Infection; Integration Host Factors; Knowledge; Life; Ligand Binding; Ligands; Lung; Measures; Mediating; Medical; Meningitis; Mission; Modeling; Molecular; Morphogenesis; Mus; Mycoses; Neuraxis; New Agents; Orphan; Pathogenesis; Phenotype; Population; Production; Protein Subunits; Regulation; Research; Research Personnel; Resistance; Role; Saccharomyces; Signal Transduction; Signal Transduction Pathway; Staging; System; Testing; Titan; United States National Institutes of Health; Virulence Factors; XCR1 gene; Yeasts; base; design; fungus; human GPRC5C protein; immunoregulation; innovation; interest; meetings; novel; pathogen; public health relevance; receptor; receptor function; receptor internalization; trafficking

DESCRIPTION (provided by applicant): The proposal focuses on G protein-coupled receptor (GPCR) signaling in the fungal pathogen Cryptococcus neoformans, which infects the lung and often disseminates to the central nervous system to cause life- threatening meningitis. There is an urgent unmet medical need for developing new drug targets for better treatment of cryptococcal infection. To meet this need, it is critical to better understand the disease mechanisms by which the fungus senses host signals and adapts to the hostile host environment. One such adaptation strategy during infection is to dramatically enlarge yeast cell size, a novel cell morphogenesis called cell gigantism or "titan" cell formation. Fungal cell gigantism during lung infection has been recently recognized as a new virulence factor that is required for disease initiation and dissemination. Despite its importance in fungal pathogenesis, the host signals and fungal receptors for titan cell induction remain unknown. Studies from the applicant demonstrated that the Gpa1 (G protein ¿ subunit) G protein signal transduction pathway is involved in the production of titan cells. A novel G protein-coupled receptor (GPCR), Gpr5, has been identified as being essential for promoting titan cell formation. These new discoveries led to the central hypothesis that fungal cells sense host specific signals through the Gpr5 orphan receptor, which then activates Gpa1-mediated signaling to regulate fungal cell morphogenesis. The long-term goal is to understand the molecular basis of cryptococcal cell gigantism in order to provide the mechanistic details needed to develop new antifungal agents that interfere with GPCR function and inhibit titan cell formation during Cryptococcus infection. Guided by strong preliminary data, the hypothesis will be tested by two specific aims: 1) Define the function of Gpr5 in G-protein signaling activation and fungal titan cell regulation, and 2) Identify and characterize host signals required for Gpr5-mediated fungal cell gigantism. Under the first aim, strains having various levels of Gpr5 activity will be used to determine the role of Gpr5 in fungal titan cell production and pathogenesis in murine models, and to characterize how Gpr5 regulates the activation of Gpa1 as measured by cellular cAMP production. Under the second aim, a spent medium that can stimulate titan cell formation in vitro will be used to identify active compounds that are responsible for Gpr5-dependent cell gigantism. A Saccharomyces-based heterologous expression system will be used to analyze potential ligands for Gpr5 activation. The approach is innovative, because we have developed an in vitro system for titan cell formation that allows us to identify host factors responsible for cell gigantism. The proposed research is significant, because it aims to understand the molecular basis of the host-pathogen interaction during the development of virulence factors, which is critical for fungal pathogenesis. Ultimately, such knowledge will facilitate efforts to design new anti-fungal agents to perturb GPCR signaling in a therapeutically beneficial manner.

描述（由适用提供）：该提案的重点是真菌病原体加密型新羊角人的G蛋白偶联受体（GPCR）信号传导，后者感染了肺部并经常将其传播到中枢神经系统中，以引起生命威胁脑膜炎。紧急未满足的医疗需求需要开发新药物，以更好地治疗隐球菌感染。为了满足这一需求，更好地了解真菌感觉宿主信号并适应敌对宿主环境的疾病机制至关重要。感染过程中的一种适应策略是急剧扩大酵母细胞大小，这是一种新型的细胞形态发生，称为细胞巨型主义或“泰坦”细胞形成。在肺部感染期间，真菌细胞巨大的疾病被认为是疾病起步和传播所必需的一种新病毒因子。尽管它在真菌发病机理中的重要性，但托管细胞诱导的宿主信号和真菌受体仍然未知。来自适用的研究表明，GPA1（G蛋白 - 亚基）G蛋白信号转移途径与钛细胞的生产有关。一种新型的G蛋白偶联受体（GPCR）GPR5已被确定为促进钛细胞形成至关重要。这些新发现导致了一个中心假设，即真菌细胞通过 GPR5孤儿受体，然后激活GPA1介导的信号传导以调节真菌细胞形态发生。长期的目标是了解加密局球细胞巨大主义的分子基础，以提供开发新的抗真菌剂所需的机械细节，这些抗真菌剂会干扰GPCR功能并抑制加密环球感染期间的钛细胞形成。在强大的初步数据的指导下，该假设将通过两个特定目的来检验：1）定义GPR5在G蛋白信号传导激活和真菌泰坦细胞调节中的功能，2）识别和表征GPR5介导的真菌细胞gigantisiss所需的宿主信号。在第一个目标下，具有不同级别GPR5活性的菌株将用于确定 真菌泰坦细胞生产和鼠模型中的发病机理中的GPR5，并表征GPR5如何调节通过细胞cAMP生产测量的GPA1的激活。在第二个目标下，可以在体外刺激泰坦细胞形成的支出培养基将用于识别负责GPR5依赖性细胞巨人的活性化合物。基于糖氢的异源表达系统将用于分析潜在的GPR5激活配体。这种方法具有创新性，因为我们已经开发了一种用于泰坦细胞形成的体外系统，使我们能够识别负责细胞巨人的宿主因素。拟议的研究很重要，因为它旨在了解病毒因素开发过程中宿主 - 病原体相互作用的分子基础，这对于真菌发病机理至关重要。最终，这种知识将促进以治疗方式设计新的抗真菌药物来扰动GPCR信号的努力。