Evolution of Aspergillus fumigatus virulence

专性需氧真核病原体在感染期间面临的一个重大挑战是 低氧微环境。在氧气耗尽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菌的毒力至关重要。然而，a 知识上的主要空白是专性好氧真菌如何在氧气耗尽的情况下获得氧气。An In 在低氧条件下进行体外实验进化实验，以确定A. 烟熏低氧适合性显示真菌菌丝体或生物膜的形态发生了意想不到的变化。一个 真菌菌落沟槽的显著增加，即所谓的皱纹菌落形态，在 进化品系，与亲本品系相比，伴随着低氧适应性的增加。重要的是，这 形态变化和低氧适应能力的增强与毒力密切相关。一次大的考试 毒力和低氧适应性增强的烟曲霉菌株收集显示相似的菌落 形态变化。对进化菌株的初步全基因组测序发现了一种突变 新的未被研究的真菌特异性基因，我们目前称之为eefA。EefA基因的过度表达或丢失 影响真菌菌落形态、低氧适应性和致病力。在这个提案中，我们将检验这一假设 菌落沟槽的增加代表了一种新的真菌氧气获取机制，这种机制对 致命性。使用分子遗传学、生化和宿主-病原体相互作用的方法，我们将定义 EefA在介导真菌氧气获取和毒力中的新功能。初步数据将eefA紧密联系在一起 菌丝能够附着并形成皱纹，从而促进氧气进入深部的真菌细胞 菌丝体。真菌菌落形态和结构如何影响烟曲霉的毒力还没有研究， 代表了一种在低氧压力下体内适应机制的新范例。因此， 拟议的研究将揭示对烟曲霉菌毒力机制的新见解，并有望 确定新的治疗方法，以阻止体内真菌的氧气获取，以改善疾病结局。

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.