Regulation of antifungal immunity by monocyte-derived dendritic cells

 描述（由申请人提供）：越来越清楚的是，真菌病原体对人类健康造成了重大负担，但目前可用的化疗在预防侵袭性真菌生长导致的死亡方面往往无效。已经提出，抗真菌药物和基于免疫的干预措施的组合可能是显着改善目前与侵袭性真菌感染相关的可怕结果的关键。在 为了实现基于免疫的治疗干预的承诺，需要更好地理解宿主保护免受真菌侵害的相关机制。烟曲霉是一种霉菌病原体，也是侵袭性曲霉病（IA）的最常见原因，IA是一种严重的感染，发生在免疫功能受损的患者中。虽然多种免疫细胞可以帮助赋予对IA的保护，但管理免疫细胞合作最终消灭分生孢子和IA预防的机制尚不清楚。使用选择性细胞耗竭策略，我们最近的研究表明，除了嗜中性粒细胞，CCR 2+炎性单核细胞（CCR 2 +Mo）及其衍生的单核细胞衍生的树突状细胞（Mo-DC）是预防IA所必需的。我们的研究表明，CCR 2 +Mo和Mo-DC对于：1）直接真菌孢子根除; 2）建立保护性炎症肺环境; 3）充分激活中性粒细胞抗真菌活性是必需的。在初步研究中，我们还发现中性粒细胞耗尽动物中IA的发展与Mo-DC分化减少和这些细胞中杀分生孢子活性降低有关。本申请中提出的研究的中心假设是中性粒细胞和CCR 2 +Mo功能是相互依赖的，持续交叉调节彼此的抗真菌活性。因此，我们的目标是询问CCR 2 +Mo和中性粒细胞交叉调节的机制，并表征其对抗真菌免疫的总体贡献。我们的第一个目标是确定CCR 2 +Mo衍生细胞如何调节中性粒细胞抗真菌效应子功能。为了鉴定嗜中性粒细胞杀分生孢子活性的相关上游调节因子，我们因此对在存在或不存在CCR 2 +Mo和Mo-DC的情况下响应于肺Af感染的嗜中性粒细胞进行了无偏转录组分析。我们的分析表明，Af感染诱导抗真菌中性粒细胞中的强I型IFN特征谱，并且去除CCR 2 +Mo损害这种反应。因此，在目标1中，我们将定义CCR 2 +Mo和Mo-DCs如何控制IFN产生，髓样细胞内在IFN信号传导在杀分生孢子效应子功能激活中的作用，并确定IFN诱导型GTP酶是否是嗜中性粒细胞杀分生孢子功能的重要效应子。在目标2中，我们将确定中性粒细胞如何控制Mo-DC分化及其抗真菌效应功能。我们将阐明特定的嗜中性粒细胞衍生因子的作用， Mo-DCs的分化和嗜中性粒细胞内在先天受体缺陷在获得嗜中性粒细胞调节途径中的作用。总之，这些研究将提供新的和重要的见解机制，介导的先天细胞合作的发展抗真菌免疫力至关重要。

 DESCRIPTION (provided by applicant): It is becoming increasingly clear that fungal pathogens pose a significant burden to human health yet currently available chemotherapies are often ineffective in preventing mortality from invasive fungal growth. It has been proposed that the combination of antifungal medications and immune-based interventions may be the key to significantly improve the dire outcomes currently associated with invasive fungal infections. In order to fulfill the promise of immune-based therapeutic interventions, a better understanding of relevant mechanisms of host protection against fungi is needed. Aspergillus fumigatus is a mold fungal pathogen and the most common cause of invasive aspergillosis (IA), a serious infection that develops in patients with compromised immune function. Although a variety of immune cells can help confer protection against IA, the mechanisms that govern immune cell cooperation culminating in the eradication of conidia and IA prevention are unclear. Using selective cell depletion strategies our recent studies have shown that, in addition to neutrophils, CCR2+ inflammatory monocytes (CCR2+Mo) and their derivative monocyte-derived dendritic cells (Mo-DCs) are required for the prevention of IA. Our studies indicate that CCR2+Mo and Mo-DCs are essential for: 1) direct fungal spore eradication; 2) establishment of a protective inflammatory lung milieu; 3) the full activation of neutrophil antifungal activities. In preliminary studies we lso find that IA development in neutrophil-depleted animals is associated with diminished Mo-DC differentiation and lower conidiacidal activity in these cells. The central hypothesis of the studis proposed in this application is that neutrophil and CCR2+Mo functions are interdependent, continuously cross-regulating each other's antifungal activities. Our goal is thus to interrogate the mechanisms of CCR2+Mo and neutrophil cross-regulation and characterize their overall contributions to anti-fungal immunity. Our first aim is to determine how CCR2+Mo derived cells regulate neutrophil anti-fungal effector functions. In order to identify relevant upstream regulators of neutrophil conidiacidal activity we thus performed an unbiased transcriptome analysis of neutrophils that responded to a pulmonary Af infection in the presence or absence of CCR2+Mo and Mo-DCs. Our analysis revealed that Af infection induces a strong type I IFN signature profile in antifungal neutrophils and that removal of CCR2+Mo impairs this response. In aim 1 we will thus define how CCR2+Mo and Mo-DCs control IFN production, the role of myeloid cell intrinsic IFN signaling in the activation of conidiacidal effector functions and determine whether IFN-inducible GTPases are essential effectors of neutrophil conidiacidal function. In aim 2 we will determine how neutrophils control Mo-DC differentiation and their antifungal effector functions. We will elucidate the role of specific neutrophil-derived factors in the differentiation of Mo-DCs and the role of neutrophil-intrinsic innate receptor deficiencies in the acquisition of neutrophil regulatory pathways. Taken together, these studies will provide novel and significant insights into the mechanisms that mediate innate cell cooperation essential for the development of antifungal immunity.