HOST FACTORS IN CRYPTOCOCCAL PATHOGENESIS

描述(由申请人提供)：隐球菌致病项目中的宿主因素摘要新生隐球菌是一种机会性病原体，可导致艾滋病患者的危及生命的疾病或免疫功能受损；肺外隐球菌感染是一种定义艾滋病的疾病。隐球菌病对人类健康有巨大影响，每年在全世界造成100多万脑膜炎病例和625,000人死亡，其中绝大多数死亡发生在艾滋病患者身上。我们研究的长期目标是确定宿主和真菌在新生梭菌致病机制中的相互作用，以提高对这些重要事件和这种破坏性的艾滋病相关机会性感染的结果的基本理解。这一应用集中在新生葡萄球菌和宿主吞噬细胞之间的相互作用，这与真菌的潜伏期、传播和毒力有关。虽然真菌吞噬已经被广泛地描述，但对于调节这一过程所需的宿主因素知之甚少，缺乏理解削弱了我们影响这种有利于宿主的相互作用的能力。我们最近在人巨噬细胞样细胞系中完成了siRNA筛选，以确定在新生葡萄球菌内化过程中起作用的激酶和磷酸酶。我们现在已经证明了两个激酶，一个参与细胞信号转导，另一个参与细胞表面修饰，是宿主原代细胞高效内化真菌所必需的。缺乏信号蛋白的小鼠也显示出隐球菌感染向大脑传播的减少。我们建议确定每种蛋白质影响吞噬作用的作用机制，以及它们在隐球菌病发病机制中的作用。我们将使用小鼠模型和原代细胞进行重点研究，利用我们在生物化学、基因表达、宿主生物学和翻译后修饰方面的专业知识来确定机制。这一强大的方法组合将阐明致病过程中的关键事件，这些事件决定了机会性微生物的生存和传播，从而决定了宿主限制疾病的能力。我们的发现还将阐明其他宿主与微生物的相互作用，并可能为抗真菌治疗提供新的方向。

DESCRIPTION (provided by applicant): Host factors in cryptococcal pathogenesis PROJECT SUMMARY Cryptococcus neoformans is an opportunistic pathogen responsible for life-threatening disease in patients with AIDS or otherwise compromised immunity; extrapulmonary cryptococcal infection is an AIDS-defining illness. Cryptococcosis has a tremendous impact on human health, causing over one million cases of meningitis and 625,000 deaths annually worldwide, with the vast majority of deaths occurring in individuals with AIDS. The long-term goal of our studies is to define host:fungal interactions in C. neoformans pathogenesis, in order to improve both fundamental understanding of these important events and the outcome of this devastating AIDS- related opportunistic infection. This application focuses on the interactions between C. neoformans and host phagocytes, which have been implicated in fungal latency, dissemination, and virulence. Although fungal en- gulfment has been broadly described, little is known about the host factors required to mediate this process, a lack of understanding that impairs our ability to influence this interaction in favor of the host. We recently com- pleted an siRNA screen in a human macrophage-like cell line to identify kinases and phosphatases that act in C. neoformans internalization. We have now shown that two kinases, one involved in cell signaling and one in cell surface modification, are required for efficient fungal internalization b host primary cells. Mice lacking the signaling protein also show reduced dissemination of cryptococcal infection to the brain. We propose to deter- mine the mechanisms of action by which each of these proteins influences phagocytosis, and their effects on the pathogenesis of cryptococcal disease. We will use mouse models and primary cells in focused studies that exploit our expertise in biochemistry, gene expression, host biology, and post-translational modifications to de- termine mechanism. This powerful combination of approaches will elucidate crucial events of pathogenesis that determine survival and dissemination of an opportunistic microbe, and thereby the host's ability to limit disease. Our findings will also illuminate other host:microbe interactions and may suggest new directions for antifungal therapy.