INITIATION OF THE IMMUNE RESPONSE TO ASPERGILLUS FUMIGATUS

项目总结 侵袭性曲霉病是毁灭性的真菌感染，也是全世界最常见的霉菌肺炎， 估计每年有20万个病例。烟曲霉--侵袭性疾病最常见的病原体 曲霉病，形成无处不在的空气传播的孢子，人类每天都会吸入。在免疫能力方面 呼吸先天免疫系统防止组织侵入菌丝的形成，这是一个关键的 免疫检查站。在恶性血液病患者的骨髓和肺移植中 接受者，以及最近在重症监护病房中患有新冠肺炎的患者，先天数字或功能缺陷 免疫功能导致侵袭性疾病。尽管有现代的抗真菌药物，但死亡率仍保持在20%- 40%在高危人群中，强调需要更好地了解分子和细胞基础 从消毒免疫到先进的基于免疫的辅助方法。 在第二个资助期，我们利用一位报道细胞死亡模式的真菌生物记者发现 中性粒细胞和单核细胞来源的树突状细胞在吞噬的真菌细胞中诱导受调控的细胞死亡。 高等真核生物可以利用低等真核生物中受调控的细胞死亡机制这一概念是新的。 而且，在烟曲霉的情况下，依赖于宿主NADPH氧化酶的活性。依赖NADPH氧化酶的真菌 杀伤是由两个新的、基本的细胞间串扰电路调制的，这两个电路涉及早期产生 GM-CSF(GM-CSF回路)和浆细胞样树突状细胞(PDC回路)。 在下一个项目期间，我们建议对GM-CSF和PDC电路有更深入的了解。在……里面 目的1，我们确定了GM-CSF的主要细胞来源，并根据初步数据，将重点放在肺 内皮细胞和上皮细胞作为中性粒细胞依赖的真菌杀灭的调节器。在目标2中，我们定义了PDC 真菌细胞或肺直接或间接激活的电路和候选传递体及测试模型 炎性环境。在目标3中，我们定义了PDC电路调节中性粒细胞的机制，以及 测试其通过磷酸戊糖在NAPDH氧化酶组装、激活和中性粒细胞代谢中的作用 介导不育性免疫的途径及其与GM-CSF途径的协同性。建议进行的研究 是重要的和创新的，因为它们整合了先天免疫串扰在肺 将内皮细胞、上皮细胞和PDC隔间和感染的髓系巨噬细胞整合为一个综合模型 对霉菌病原体的呼吸道免疫能力。了解诱导、调节和参与者 先天免疫串扰解决了一个关键的知识鸿沟，这将为免疫增强策略提供信息 脆弱的患者群体。

PROJECT SUMMARY Invasive aspergillosis is devastating fungal infection and the most common form of mold pneumonia worldwide, with an estimated 200,000 cases annually. Aspergillus fumigatus, the most common etiologic agent of invasive aspergillosis, forms ubiquitous airborne spores that humans inhaled on daily basis. In immune competent individuals the respiratory innate immune system prevents the formation of tissue-invasive hyphae, a critical immunologic checkpoint. In patients with hematologic malignancies, in bone marrow and lung transplant recipients, and recently, in intensive care unit patients with COVID-19, numeric or functional defects in innate immune function lead to invasive disease. Despite contemporary antifungal drugs, mortality rates remain at 20- 40% in high risk groups, underscoring the need for improved understanding of the molecular and cellular basis of sterilizing immunity to advance immune-based adjunctive approaches. In the second funding period, we harnessed a fungal bioreporter that reports the mode of cell death to discover that neutrophils and monocyte-derived dendritic cells induce a regulated cell death in engulfed fungal cells. The concept that a higher eukaryote can exploit a regulated cell death machinery in a lower eukaryote is novel and, in the case of A. fumigatus, depends on host NADPH oxidase activity. NADPH oxidase-dependent fungal killing is modulated by two novel, essential intercellular crosstalk circuits that involves the early production of GM-CSF (GM-CSF circuit) and plasmacytoid dendritic cells (pDC circuit). During the next project period, we propose to gain a deeper understanding of the GM-CSF and pDC circuits. In Aim 1, we identify the essential cellular source of GM-CSF and, based on preliminary data, focus on pulmonary endothelial and epithelial cells as regulators of neutrophil-dependent fungal killing. In Aim 2, we define the pDC circuit and candidate transmitters and test models of direct or indirect activation by fungal cells or the lung inflammatory milieu. In Aim 3, we define the mechanisms by which the pDC circuit regulates neutrophils, and test its role in NAPDH oxidase assembly, activation, and neutrophil metabolism via the pentose phosphate pathway and its cooperativity with the GM-CSF circuit to mediate sterilizing immunity. The proposed studies are significant and innovative because they integrate innate immune crosstalk between the pulmonary endothelial, epithelial, and pDC compartments and infected myeloid phagocytes into a comprehensive model of respiratory immunity against mold pathogens. Understanding the induction, regulation, and participants of innate immune crosstalk addresses a critical knowledge gap that will inform immune-enhancing strategies in vulnerable patient groups.