Genetic Determinants of Aspergillus host-pathogen interactions

我们工作的长期目标是通过以下方法降低曲霉菌感染相关的发病率和死亡率： 改善宿主-病原体相互作用的结果。烟曲霉是主要的空气真菌病原体 并导致一系列临床综合征，其严重程度取决于宿主免疫状态。 侵袭性肺曲霉菌病和播散性感染可发生在严重免疫功能低下的宿主中 并且通常与高达90%的死亡率相关。在免疫活性宿主中，A.烟曲霉定殖 可导致慢性肺曲霉菌病（CPA），这是一种最近定义的诊断为 这些标准每年影响160万人以上。许多CPA患者都有潜在的 呼吸道疾病，如哮喘或囊性纤维化，这些疾病因存在 真菌虽然多种病原体相关分子模式（PAMP）驱动宿主识别和 反应是已知的，揭示了新的真菌分子途径，可以作为治疗靶点， 增强或掩蔽PAMP展示和/或生物合成可以证明是调节宿主 改善结果的响应。为了解决这个问题，我们利用炎症体的激活， 细胞内复合物，检测致病生物体启动炎症反应，作为一种工具，以揭示 具有改变的激活宿主反应能力的曲霉突变体。我们已经完成了初步筛选， 使用A.烟曲霉 蛋白激酶破坏文库。在筛选的118个蛋白激酶破坏突变体中， 我们发现了7个A烟曲霉蛋白激酶显著升高（n=2）或降低（n=5） 破坏后炎性小体依赖性IL-1β分泌。引人注目的是，蛋白激酶的破坏 诱导增加的IL-1β释放的突变体编码磷酸中继传感器组氨酸激酶（phkA和fhk 3）， 蛋白激酶的一个亚类，直接感知环境和细胞内变化， 激活应激反应信号。由PhkA和Fhk 3控制的分子途径是未知的，因为它们都 HK在很大程度上没有特征。虽然HK信号传导的主要结果是激活应激反应 上调转录因子活性以响应环境刺激的下游途径， 所有A.烟曲霉HK仍然没有描述。我们的工作将描绘A。烟曲霉 组氨酸激酶（HK）依赖性宿主应答机制（Aim 1）和鉴定A.烟曲霉转录 炎性小体激活的调节剂（Aim 2）。通过完成拟议的目标，我们将 真菌分子途径介导的冬虫夏草诱导的宿主反应。这项工作对未来至关重要 开发新的治疗方法，以激活对侵入性感染的保护 或减轻慢性感染期间有害的宿主反应。

The long-term goal of our work is to reduce the morbidity and mortality associated with Aspergillus infections by improving outcomes of host-pathogen interactions. Aspergillus fumigatus is the major airborne fungal pathogen and is responsible for a range of clinical syndromes, the severity of which is dependent on host immune status. Invasive pulmonary aspergillosis and disseminated infections can occur in severely immunocompromised hosts and are often associated with mortality rates of up to 90%. In immune competent hosts, A. fumigatus colonization can lead to chronic pulmonary aspergillosis (CPA), a clinical manifestation with recently defined diagnostic criteria that impacts upwards of 1.6 million individuals per year. Many individuals with CPA have underlying respiratory conditions, such as asthma or cystic fibrosis, that are further exacerbated by the presence of the fungus. Although multiple Pathogen-Associated Molecular Patterns (PAMPs) driving host recognition and response are known, uncovering novel fungal molecular pathways that could serve as therapeutic targets to enhance or mask PAMP display and/or biosynthesis could prove useful therapeutic targets to modulate host response for improved outcomes. To address this, we utilized activation of the inflammasome, a multiprotein intracellular complex that detects pathogenic organisms to initiate inflammatory responses, as a tool to uncover Aspergillus mutants with altered abilities to activate host response. We have completed a preliminary screen to measure IL-1β secretion from a macrophage differentiated human monocyte cell line employing an A. fumigatus protein kinase disruption library recently generated in our lab. Of 118 protein kinase disruption mutants screened, we identified seven A. fumigatus protein kinases that either significantly increased (n=2) or decreased (n=5) inflammasome-dependent IL-1β secretion upon disruption. Strikingly, both of the protein kinase disruption mutants that induced increased IL-1β release encode phospho-relay sensor histidine kinases (phkA and fhk3), a sub-class of protein kinases that directly sense environmental and intracellular changes and subsequently activate stress response signaling. The molecular pathways controlled by PhkA and Fhk3 are unknown, as both HKs are largely uncharacterized. Although a major consequence of HK signaling is activation of stress responses pathways that upregulate transcription factor activity to respond to environmental stimuli, the downstream transcriptional effectors for all A. fumigatus HKs remain undescribed. Our work will delineate A. fumigatus histidine kinase (HK)-dependent mechanisms of host response (Aim 1) and identify A. fumigatus transcriptional regulators of inflammasome activation (Aim 2). Through completion of the proposed Aims, we will delineate fungal molecular pathways mediating Aspergillus-induced host response. This work is essential for future development of novel therapeutic approaches targeted towards activating protection against invasive infections or mitigating harmful host-response during chronic infections.