Autophagy and ocular toxoplasmosis

描述（由申请人提供）：弓形虫是世界上最常见的视网膜脉络膜炎病因。尽管使用抗生素，眼部弓形虫病仍会复发，并且仍然是视力丧失的重要原因，特别是在患有先天性感染的儿童以及老年人和免疫抑制者中。不幸的是，我们对眼弓形虫病的保护机制的理解是零碎的。大胶质细胞、小胶质细胞和T细胞是眼弓形虫病细胞浸润的主要成分。这些细胞之间相互作用的一个重要事件是刺激巨噬细胞/小胶质细胞上表达的CD 40。我们确定了一种新的模式，免疫系统通过CD 40杀死T。刚地。CD 40在巨噬细胞和视网膜小胶质细胞中诱导杀弓形虫活性。这依赖于自噬，自噬是一种将寄生虫靶向溶酶体降解的过程。这一发现可能是眼弓形虫病的关键，因为这种疾病的体内控制需要CD 40。因此，研究CD 40诱导的自噬的调控将可能为T细胞的根除找到新的分子靶点。弓形虫病的治疗，将有望防止这种疾病的复发。本申请的目的是了解巨噬细胞和视网膜小胶质细胞中的CD 40信号传导如何控制眼弓形虫病以及T.弓形虫破坏了这些信号。这项研究的中心假设是，CD 40通过蛋白激酶激活和诱导自噬介导眼内对弓形虫病的抵抗。与此相反，T.弓形虫和由寄生虫触发的细胞因子使用一种策略来损害自噬的最佳激活所需的信号传导，从而使寄生虫逃避根除。这一假设将使用免疫化学研究以及阻断特定囊泡运输分子的遗传方法进行测试。在第一个具体的目标，我们将确定是否自噬和蛋白激酶激活诱导的CD 40介导的抵抗眼弓形虫病。在第二个目标中，我们将确定细胞因子阻止自噬的最佳诱导的细胞内事件，并测试这些事件的抑制是否改善了眼弓形虫病的控制。这项工作可能会导致新的战略，以消除T。以及基于调节自噬和/或CD 40信号传导治疗眼弓形虫病。

DESCRIPTION (provided by applicant): Toxoplasma gondii is the most common cause of retinochoroiditis in the world. Ocular toxoplasmosis relapses despite the use of antibiotics and remains an important cause of loss of visual acuity especially in children with congenital infection as well as the elderly and the immunosuppressed. Unfortunately, our understanding of the mechanisms of protection against ocular toxoplasmosis is fragmentary. Macrophages, microglia and T cells are the major components of the cell infiltrates in ocular toxoplasmosis. An important event in the interaction between these cells is the stimulation of CD40 expressed on macrophages/microglia. We identified a new paradigm by which the immune system through CD40 kills T. gondii. CD40 induces toxoplasmacidal activity in macrophages and retinal microglia. This is dependent on autophagy, a process that targets the parasite to lysosomal degradation. This finding is likely key to ocular toxoplasmosis because in vivo control of this disease requires CD40. Thus, studying the regulation of CD40-induced autophagy will likely identify new molecular targets for eradication of T. gondii and for therapy of ocular toxoplasmosis that will hopefully prevent relapse of this disease. The objective of this application is to understand how CD40 signaling in macrophages and retinal microglia controls ocular toxoplasmosis and how T. gondii subverts these signals. The central hypothesis for the proposed research is that, CD40 mediates resistance against toxoplasmosis in the eye through protein kinase activation and induction of autophagy. In contrast, T. gondii and cytokines triggered by the parasite use a strategy to impair the signaling needed for optimal activation of autophagy allowing the parasite to evade eradication. This hypothesis will be tested using immunochemical studies as well as genetic approaches that block specific vesicular trafficking molecules. In the first specific aim we will determine if autophagy and protein kinase activation induced by CD40 mediate resistance to ocular toxoplasmosis. In the second aim, we will identify the intracellular events by which cytokines prevent optimal induction of autophagy and test whether inhibition of these events improves control of ocular toxoplasmosis. The proposed work may lead to new strategies to eradicate T. gondii and treat ocular toxoplasmosis based on modulation autophagy and/or CD40 signaling.