PKA: Stress Response and Virulence in A. fumigatus

PKA：烟曲霉的应激反应和毒力

• 批准号: 7176162
• 负责人: Judith C Rhodes
• 金额: $ 29.11万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7176162
• 关键词: Acids; Address; Alveolar Macrophages; Animal Model; Animals; Aspergillosis; Aspergillus fumigatus; Autoradiography; Carbon; Catalytic Domain; Cell Line; Complement; Compost; Condition; Consensus; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclophosphamide; Data; Development; Eukaryota; Eukaryotic Cell; Exposure to; Gene Deletion; Genes; Genetic; Growth; Host Defense; Hyphae; Hyphomycetes; Immune system; Immunocompromised Host; Infection; Invasive; Label; Lung; Measures; Mediating; Mediator of activation protein; Modeling; Molds; Morbidity - disease rate; Movement; Mus; Mutagenesis; Nitrogen; Nuclear Localization Signal; Nutritional; Nutritive Value; Organism; Pathway interactions; Patients; Pattern; Phagocytes; Phagocytosis; Phagolysosome; Phosphoproteins; Phosphorylation; Physiological; Play; Post-Translational Regulation; Predisposition; Property; Proteins; Proteomics; Recycling; Regulation; Regulator Genes; Research Personnel; Risk; Role; Saccharomyces; Series; Signal Pathway; Signal Transduction; Source; Stress; Temperature; Testing; Therapeutic Agents; Time; Triamcinolone; Two-Dimensional Gel Electrophoresis; Video Microscopy; Virulence; Yeasts; biological adaptation to stress; fungus; immunosuppressed; killings; macrophage; mortality; mutant; nucleocytoplasmic transport; pathogen; programs; response; stressor

DESCRIPTION (provided by the applicant): Aspergillus fumigatus is the most common opportunistic hyphomycete, and invasive pulmonary aspergillosis caused by A. fumigatus continues to have high morbidity and mortality in neutropenic patients. The organism is a ubiquitous fungus that thrives in compost heaps where it is a major contributor to carbon and nitrogen recycling. In order to initiate infection, airborne conidia must survive a stressful transition from the compost heap to the mammalian lung. Temperature shift, change in nutritional availability, and attack by inimical host defenses are potent stressors to which the fungus must respond through environmental sensing and genetic and physiologic reprogramming. The protein kinase A (PKA) pathway has been identified in Saccharomyces as one of the primary signaling pathways involved in reprogramming in response to stress, however, little is known about the importance of this pathway in the growth and virulence of filamentous fungi. This proposal will test the hypothesis that intact signaling through PKA is required for induction of protective stress responses by A. fumigatus. This hypothesis will be tested through a series of four aims. In aim 1, deletion mutants of the regulatory and the catalytic subunit, and their respective complemented strains, will be tested in a murine model for virulence. The second aim will determine the extent to which mutants with unregulated PKA are susceptible to stressors such as oxidative damage, DMA damage, and extremes of pH. Aims 3 and 4 will address post-translational regulation of the PKA pathway in A. fumigatus. In aim 3, changes in phosphorylation patterns in the mutants will be used to define the PKA phosphoproteome. Phosphorylation state of the wild type following stress will aid in identifying stress-related targets of PKA phosphorylation. Compartmentalization plays a key role in eukaryotes in controlling the activity of PKA and some of its primary targets. Therefore, in aim 4, regulation of PKA activity will be examined by determining the subcellular localization of the PKA subunits of A. fumigatus under various nutritional and stress-induced states. The results of these studies should elucidate the role of PKA in the stress response of A. fumigatus and its influence on virulence.

描述（由申请人提供）：烟曲霉是最常见的机会性丝菌，由烟曲霉引起的侵袭性肺曲霉病在中性粒细胞减少症患者中仍然具有较高的发病率和死亡率。这种生物体是一种普遍存在的真菌，​​在堆肥堆中茁壮成长，是碳和氮循环的主要贡献者。为了引发感染，空气中的分生孢子必须在从堆肥堆到哺乳动物肺部的紧张过渡中幸存下来。温度变化、营养供应的变化以及敌对宿主防御的攻击是真菌必须通过环境感知以及遗传和生理重编程来应对的潜在压力源。蛋白激酶 A (PKA) 通路已在酵母菌中被确定为参与应激响应重编程的主要信号通路之一，然而，人们对该通路在丝状真菌生长和毒力中的重要性知之甚少。 该提案将检验以下假设：烟曲霉诱导保护性应激反应需要通过 PKA 的完整信号传导。这一假设将通过一系列四个目标进行检验。在目标 1 中，将在小鼠模型中测试调节亚基和催化亚基的缺失突变体及其各自的互补菌株的毒力。第二个目标是确定 PKA 不受调控的突变体对氧化损伤、DMA 损伤和极端 pH 等应激源的敏感程度。目标 3 和 4 将解决烟曲霉 PKA 途径的翻译后调控。在目标 3 中，突变体磷酸化模式的变化将用于定义 PKA 磷酸化蛋白质组。应激后野生型的磷酸化状态将有助于识别应激相关的 PKA 磷酸化靶点。在真核生物中，区室化在控制 PKA 及其一些主要靶标的活性方面发挥着关键作用。因此，在目标 4 中，将通过确定烟曲霉 PKA 亚基在各种营养和应激诱导状态下的亚细胞定位来检查 PKA 活性的调节。这些研究的结果应该阐明 PKA 在烟曲霉应激反应中的作用及其对毒力的影响。