Recognition and Phagocytosis of Candida Albicans by the innate immune system

描述(申请人提供)：白色念珠菌，最常见的分离人类真菌病原体，已经开发出几种逃避免疫检测和杀死的机制。首先，假丝酵母菌能够在细胞壁中掩盖免疫原。其次，在巨噬细胞吞噬后，念珠菌能够进行菌丝形态发生。这些丝状细胞能够穿透巨噬细胞，释放真菌感染其他组织。包括高通量流式细胞仪、全基因组慢病毒RNAi文库和基因删除文库在内的新技术现在可以系统地识别宿主(巨噬细胞)和病原体(念珠菌)途径，这些途径是真菌发病的基础。这些途径的识别对于开发新的药物靶点是至关重要的，这些药物靶标既可以针对念珠菌，也可以刺激增强的巨噬细胞/免疫功能。我的建议的目标是：1.使用全基因组RNAi文库来鉴定吞噬白色念珠菌和诱导吞噬的念珠菌丝状生长所需的巨噬细胞基因。2.鉴定白念珠菌突变体，通过高通量流式细胞术增加标志性细胞表面成分的暴露，并确定它们在巨噬细胞的炎症反应和吞噬反应中的作用。3.利用念珠菌细胞表面突变体与巨噬细胞敲除株共同构建病原体-巨噬细胞识别途径。与公共卫生相关：系统性念珠菌感染是一种危及生命的疾病，死亡率为40%。我提议的研究将确定念珠菌作为病原体成功所需的真菌和宿主过程。了解念珠菌用来避免被免疫系统检测和杀死的方法是开发阻断这些过程的药物的第一步。

DESCRIPTION (provided by applicant): Candida albicans, the most frequently isolated human fungal pathogen, has developed several mechanisms to evade immune detection and killing. First, Candida is able to mask immunogens in its cell wall. Second, upon phagocytosis by macrophages, Candida is able to undergo hyphal morphogenesis. These filamentous cells are able to pierce through the macrophage and release the fungus to infect other tissues. New technologies, including high-throughput FACS, genome-wide lentivirus RNAi libraries, and gene deletion libraries now allow for the systematic identification of host (macrophage) and pathogen (Candida) pathways that are fundamental to fungal pathogenesis. The identification of such pathways is essential for the development of new pharmaceutical targets that either specifically target Candida or stimulate enhanced macrophage/immune function. The goals of my proposal are to: 1. Use genome-wide RNAi libraries to identify macrophage genes required for phagocytosis of C. albicans and the induction of filamentation of phagocytosed Candida. 2. Identify Candida albicans mutants that have increased exposure of signature cell surface components by high throughput FACS and determine their role in responses inflammatory and phagocytic responses by macrophages. 3. Utilize the Candida cell surface mutants together with the macrophage knockdown lines to reconstruct the pathogen-macrophage recognition pathway. Relevance to public health: Systemic Candida infection is a life-threatening condition that has a mortality rate of 40%. The studies I have proposed will identify both fungal and host processes required for the success of Candida as a pathogen. Understanding the methods that Candida uses to avoid detection and killing by the immune system is the first step towards development of drugs to block these processes.