Leishmania amazonensis sabotages host SUMOylation: a novel virulence mechanism for macrophage invasion

这项建议的重点是在研究一种新的利什曼原虫毒力策略涉及 在哺乳动物巨噬细胞的成功感染中-抑制蛋白质 SUMO化。这种毒力机制的发现是基于细胞的 使用果蝇细胞进行全基因组RNAi筛选。几个被击倒的 SUMO化因子影响利什曼原虫无鞭毛体型感染 在哺乳动物巨噬细胞中的进一步研究表明，L. 亚马逊线虫感染抑制宿主细胞SUMO化和SUMO因子的耗竭 增强寄生虫复制。 SUMO化是一种翻译后修饰，其中一个小的成员 泛素样调节蛋白（SUMO）与靶蛋白结合。sumo化 调节许多蛋白质的功能或活动， SUMO化的蛋白质已经在HeLa和U2 OS细胞系中被分类。鉴于其 普遍存在的作用，我们假设SUMO化抑制是一个重要的， 毒力机制亚马逊河。 支持这一观点的是，感染SUMO耗竭的巨噬细胞产生了更大的 寄生虫空泡（复制生态位）和较高的寄生虫增殖。的 SUMO化在寄生虫生物发生和寄生虫复制中的作用 将进行更详细的研究。 在更广泛的背景下，我们还将确定寄生虫如何影响SUMO化， 这种毒力策略在小鼠感染中的相关性是什么。简单地说，我们将 确定宿主SUMO机器的哪些组件是寄生虫的目标， 鉴定寄生虫毒力因子。SUMO化抑制与 将在SUMO化因子缺陷的小鼠感染中评价利什曼病 以及不同利什曼原虫株毒力与SUMO化相关的研究 抑制能力

This proposal is focused in the study a novel Leishmania virulence strategy involved in the successful infection of mammalian macrophages — inhibition of protein SUMOylation. This virulence mechanism was discovered has a result of a cell-based genome-wide RNAi screen using Drosophila cells. The knockdown of several SUMOylation factors affected infection by amastigotes forms of Leishmania amazonensis, and further studies in mammalian macrophages revealed that L. amazonensis infection inhibited host cell SUMOylation and depletion of SUMO factor enhanced parasite replication. SUMOylation is a post-translational modification in which a member of Small Ubiquitin-like MOdifier protein (SUMO) is conjugated to target proteins. SUMOylation regulates numerous protein functions or activities, and over six thousand different SUMOylated proteins have been cataloged in HeLa and U2OS cell lines. Given its ubiquitous role in cells, we hypothesize that SUMOylation inhibition is one important virulence mechanisms of L. amazonensis. Supporting this idea, infection of SUMO depleted macrophages produced larger parasitophorous vacuoles (the replicative niche) and higher parasite proliferation. The participation of SUMOylation in parasitophorous biogenesis and in parasite replication will be studied in more detail. In a broader context, we will also determine how parasites affect SUMOylation and what is the relevance of this virulence strategy in mouse infection. Briefly, we will determine what components of the host SUMO machinery are targeted by parasites and identify parasitic virulence factors. The relevance of SUMOylation inhibition in leishmaniasis will be evaluated in infections of mice deficient in SUMOylation factors and in studies correlating virulence of different leishmania strains and SUMOylation inhibition capacity.