Characterization of the ESX-5 secretome and its impact on virulence mechanisms of Mycobacterium tuberculosis

摘要 结核分枝杆菌(Mtb)是一种人类病原体，可导致严重的发病率和死亡率。 全世界。越来越多的结核病病例是由多种药物和极端耐药引起的 结核杆菌菌株，强调了对新疗法的需要。结核分枝杆菌通过操纵受感染的细胞来实现 毒力和为此目的，结核分枝杆菌需要分泌与宿主细胞相互作用的蛋白质。第一类7 分泌系统(T7SS)最初在分枝杆菌中被发现，此后又有四个系统被发现 (ESX-1至ESX-5)。ESX-5系统的一个核心四基因序列已被复制 在结核分枝杆菌基因组中有三次(ESX-5a、ESX-5b和ESX-5c)。在这里，我们提出了新的假设，即 复制的ESX-5区域在ESX-5分泌的特定亚群的分泌中具有辅助功能 蛋白质。在AIM1中，我们计划产生Mtb缺失突变体，以确定缺失Mtb的影响 ESX-5辅助系统对宿主细胞反应和毒力的影响。在AIM2中，我们将使用蛋白质组学 表征与ESX-5附属系统相关的分泌体的方法。这些研究将 为鉴定特定的、ESX-5分泌的、对结核分枝杆菌至关重要的效应蛋白奠定基础 致命性。因此，拟议的研究最终将有助于设计更好的重组疫苗菌株。 和/或药物开发的新一代靶点。

Abstract Mycobacterium tuberculosis (Mtb) is a human pathogen that causes significant morbidity and mortality worldwide. An increasing number of tuberculosis cases are caused by multi-drug and extreme-drug resistant Mtb strains, underscoring the need for novel therapeutics. Mtb manipulates infected cells in order to achieve virulence and to this end Mtb needs to secrete proteins, which will interact with the host cell. The first type 7 secretion system (T7SS) was originally identified in mycobacteria and since then four additional systems have been described (ESX-1 through ESX-5). A core, four-gene sequence of the ESX-5 system has been duplicated three times in the Mtb genome (ESX-5a, ESX-5b and ESX-5c). Here we propose the novel hypothesis that the duplicated ESX-5 regions have an accessory function in the secretion of specific subgroups of ESX-5-secreted proteins. In AIM1 we plan to generate Mtb deletion mutants in order to determine the impact of the deletion of the ESX-5 accessory systems on host cell responses and virulence. In AIM2 we will use proteomics approaches to characterize the secretomes associate with the ESX-5 accessory systems. These studies will lay the groundwork to enable the identification of specific, ESX-5-secreted, effector proteins critical for Mtb virulence. The proposed research will thus ultimately aid in the design of better recombinant vaccines strains and/or the generation novel targets for drug development.