Evolution of Aspergillus fumigatus virulence

烟曲霉毒力的演变

基本信息

批准号：
10238878
负责人：
Robert Andrew Cramer
金额：
$ 45.49万
依托单位：
DARTMOUTH COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-25 至 2023-07-10
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10238878
关键词：
Adhesions Adrenal Cortex Hormones Aerobic Affect Alleles Animal Model Antifungal Agents Antifungal Therapy Area Aspergillus fumigatus Attenuated Biochemical Biogenesis Biological Biological Assay Biology Cell Wall Cells Collection Complement Complex Data Diffusion Disease Disease Outcome Disease Progression Dose Drug Tolerance Environment Evolution Foundations Gene Family Genes Genetic Health Heterogeneity Human Hyphae Hypoxia Image Immune In Vitro Infection Iron Knowledge Link Mediating Microbial Biofilms Microelectrodes Modeling Molds Molecular Molecular Genetics Morphology Mutagenesis Mutation Mycelium Mycoses Oxidative Stress Oxygen Pathogenesis Pathway interactions Patient-Focused Outcomes Patients Phenotype Physiological Production Proteins Research Role Site Stress Structure Study models Surface Testing Virulence base biological adaptation to stress chemotherapy clinically relevant experimental study fitness fungus genetic analysis genome sequencing improved in vivo in vivo Model insight mutant new therapeutic target novel novel therapeutic intervention overexpression pathogen pathogenic fungus patient population protein protein interaction response therapeutic development trait transcriptome transcriptome sequencing whole genome

项目摘要

A significant challenge faced by obligate aerobic eukaryotic pathogens during infection is low oxygen microenvironments. The ability to acquire sufficient oxygen in the face of oxygen depletion has now been shown to be critical for Aspergillus fumigatus and other eukaryotic pathogen's virulence. However, a major gap in knowledge is how obligate aerobic fungi acquire oxygen in the face of oxygen depletion. An in vitro experimental evolution experiment conducted under low oxygen conditions to identify mechanisms of A. fumigatus hypoxia fitness revealed an unexpected change in the fungal mycelium, or biofilm, morphology. A substantial increase in fungal colony furrowing, a so called rugose colony morphology, was observed in the evolved strain with a concomitant increase in hypoxia fitness compared to the parental strain. Importantly, this morphological change and increased hypoxia fitness strongly correlates with virulence. Examination of a large collection of A. fumigatus strains with increased virulence and hypoxia fitness reveals similar colony morphological changes. Preliminary whole genome sequencing of the evolved strain identified a mutation in a novel unstudied fungal specific gene we currently call eefA. Over-expression or loss of eefA dramatically affects fungal colony morphology, hypoxia fitness, and virulence. In this proposal, we will test the hypothesis that increased colony furrowing represents a novel mechanism for fungal oxygen acquisition that is critical for virulence. Using molecular genetics, biochemical, and host-pathogen interaction approaches, we will define the novel function of eefA in mediating fungal oxygen acquisition and virulence. Preliminary data strongly link eefA with the ability of hyphae to adhere and form furrows that promote oxygen access to fungal cells deep within the mycelium. How fungal colony morphology and structure affects A. fumigatus virulence is unstudied and represents a new paradigm for a mechanism of in vivo fitness in the face of low oxygen stress. Consequently, the proposed studies will reveal new insights into A. fumigatus virulence mechanisms and are expected to identify novel therapeutic approaches to thwart fungal oxygen acquisition in vivo to improve disease outcomes.

专性需氧真核病原体在感染过程中面临的一个重大挑战是低氧微环境。在缺氧的情况下获得足够氧气的能力现在已经已被证明对烟曲霉和其他真核病原体的毒力至关重要。然而，一个知识上的主要差距是专性需氧真菌在缺氧时如何获取氧气。一个在在低氧条件下进行的体外实验进化实验以确定A. 烟曲霉缺氧适应性揭示了真菌菌丝体或生物膜形态的意外变化。一个观察到真菌菌落的沟纹显着增加，即所谓的皱纹菌落形态。与亲本品系相比，进化品系伴随着缺氧适应性的增加。重要的是，这形态变化和缺氧适应性的增加与毒力密切相关。大检查毒力增加和缺氧适应性增强的烟曲霉菌株的收集揭示了相似的菌落形态变化。对进化菌株的初步全基因组测序发现了一个突变一种新的未经研究的真菌特异性基因，我们目前称为 eefA。 eefA 过度表达或显着缺失影响真菌菌落形态、缺氧适应性和毒力。在这个提案中，我们将测试假设增加菌落犁沟代表了真菌获取氧气的一种新机制，这对于真菌的生长至关重要毒力。使用分子遗传学、生物化学和宿主-病原体相互作用方法，我们将定义 EefA 在介导真菌氧气获取和毒力方面的新功能。初步数据与 eefA 密切相关具有菌丝粘附和形成沟槽的能力，促进氧气进入真菌细胞深处菌丝体。真菌菌落形态和结构如何影响烟曲霉毒力尚未得到研究，并且代表了面对低氧应激时体内健身机制的新范例。最后，拟议的研究将揭示烟曲霉毒力机制的新见解，并有望确定新的治疗方法来阻止真菌体内获取氧气以改善疾病结果。