Genetics and visualization of innate host response to C. albicans infection in vi

描述（由申请人提供）：菌血症是第四常见的医院感染，并导致不成比例的死亡率。白色念珠菌是一种普遍存在的真菌，也是人类真菌性疾病的最常见原因。播散性血流念珠菌血症具有>30%的可归因死亡率，并且与化疗诱导的中性粒细胞减少症、器官移植、原发性遗传缺陷（如慢性肉芽肿病）和医疗程序（如提供直接进入血流的静脉内导管插入术）相关。人类流行病学和小鼠实验已经证明，先天免疫功能是抵抗播散性疾病的主要屏障，但巨噬细胞在疾病应答和清除中的作用仍不清楚。不幸的是，技术限制限制了我们测试巨噬细胞在感染的自然环境中的作用的能力。分离的巨噬细胞对C.白念珠菌在缺乏基质和可溶性线索的情况下导致了这样的想法，即它们发挥限制感染的边缘作用，但可以促进疾病在组织中的传播。然而，我们最近的非侵入性成像，使用一个新的透明模型，传播的斑马鱼感染，表明巨噬细胞在其自然环境中有一个增强的能力，以限制增殖 和C.白色念珠菌我们假设巨噬细胞限制了C.白色念珠菌，但促进全身感染的传播。我们将利用斑马鱼感染模型来确定巨噬细胞在限制真菌增殖和促进传播中的作用，使用活体实时成像，基因敲除，靶向细胞消融和真菌突变体。带有标记的巨噬细胞的转基因鱼将用于跟踪体内单个真菌-吞噬细胞的相互作用，我们将消融和扰动巨噬细胞以确定它们在调节真菌形态发生转换、增殖和传播中的作用。拟议的实验将测试先天免疫的基本问题，这些问题在哺乳动物模型中一直难以解决，通过利用透明斑马鱼模型的优势。拟议的实验结果将产生一个更完整的基本了解的机制，先天免疫念珠菌血症，并设置了新的宿主和病原体的途径调节这些巨噬细胞活性的靶向筛选阶段。真菌感染过程中巨噬细胞活性机制的发现有可能导致新的治疗干预措施。 公共卫生相关性：传染病影响全世界的人类，并在美国造成显著的死亡率和发病率。目前控制真菌病的方法是不够的，特别是在免疫功能低下的患者群体中，因此研究替代治疗至关重要。这项研究的一个长期目标是利用宿主-病原体相互作用的基本信息来开发治疗真菌疾病的疗法。

DESCRIPTION (provided by applicant): Candidemia is the 4th most common nosocomial infection, and leads to disproportionate mortality. Candida albicans is a ubiquitous commensal and the most frequent cause of fungal disease in humans. Disseminated bloodstream candidemia carries a >30% attributable mortality and is associated with chemotherapy-induced neutropenia, organ transplantation, primary genetic defects such as chronic granulomatous disease, and medical procedures such as intravenous catheterization that provide direct access to the bloodstream. Human epidemiology and mouse experiments have demonstrated that innate immune function is the primary barrier against disseminated disease, yet the role of macrophages in response and clearance of disease is still unclear. Unfortunately, technical constraints have limited our ability to test the roles of macrophages in their natural context of infection. The relatively weak capacity of isolated macrophages to destroy C. albicans in the absence of matrix and soluble cues has led to the idea that they play a marginal role limiting infection but could promote dissemination of disease among tissues. However, our recent non-invasive imaging, using a new transparent model of disseminated Candida-zebrafish infection, indicates that macrophages in their natural context have an enhanced ability to limit proliferation and germination of C. albicans. We hypothesize that macrophages limit filamentous growth of C. albicans but promote dissemination of infection throughout the body. We will exploit the zebrafish infection model to determine the role of macrophages in limiting fungal proliferation and promotion of dissemination using intravital real-time imaging, gene knockdown, targeted cell ablation, and fungal mutants. Transgenic fish with marked macrophages will be used to follow individual fungal-phagocyte interactions in vivo, and we will ablate and perturb macrophages to determine their role in regulating fungal morphogenetic switching, proliferation and dissemination. The proposed experiments will test basic questions of innate immunity that have been intractable in mammalian models by exploiting the advantages of the transparent zebrafish model. The results of the proposed experiments will yield a more complete basic understanding of the mechanisms underlying innate immunity to candidemia and set the stage for targeted screening for novel host and pathogen pathways regulating these macrophage activities. The discovery of mechanisms underlying macrophage activity during fungal infection has the potential to lead to new therapeutic interventions. PUBLIC HEALTH RELEVANCE: Infectious diseases affect humans worldwide and cause significant mortality and morbidity in the United States. Current methods to control fungal disease are inadequate, especially in the immunocompromised patient population, so it is critical to investigate alternative treatments. A long-term goal of this investigation involves leveraging basic information about host-pathogen interaction to develop therapeutics to treat fungal disease.