The role of immunity in shaping Mycobacterium tuberculosis metabolism

项目摘要 结核分枝杆菌（Mtb）是导致感染性疾病死亡的主要原因， 每年死亡。为了使结核分枝杆菌在宿主体内茁壮成长，细菌必须获得营养，包括碳 这对增长至关重要。MTB可以使用四种主要的碳源来满足其对 碳利用结核分枝杆菌主要存在于宿主巨噬细胞的吞噬体内， 碳源来自巨噬细胞，而在这个生态位。在这个隔间里，结核病也 经历各种各样的压力，包括活性氮物质（RNS）压力。以前的工作 已经显示Mtb在体外暴露于一氧化氮（NO）导致蛋白质的亚硝基化， 对糖酵解至关重要。我们实验室的其他初步数据显示， 转座子文库在体外与NO的结合导致脂肪酸降解的重要性增加， 减少依赖糖酵解途径在NO暴露。这让我们假设， 暴露于RNS应激导致结核分枝杆菌对碳的利用发生变化。为了开始识别RNS 胁迫影响碳利用，Aim 1将利用不能利用或不能利用的菌株文库。 获取每一种碳源。该文库将在单一碳源存在下生长 和RNS，并将监测每种菌株的生长，以确定RNS应力如何影响 每个突变体在每个碳源上生长的能力。在目标2中，该文库将用于感染 巨噬细胞和野生型或缺乏诱导NO表达能力的小鼠。这些 研究将使我们能够确定实际感染条件如何影响结核分枝杆菌利用各种 碳源。最后，目标3将集中于确定RNS应激导致 Mtb的碳使用变化。这些研究将为结核分枝杆菌如何利用碳提供重要数据 在应激条件下，以及允许体内碳利用变化的机制。

Project Summary Mycobacterium tuberculosis (Mtb) is the leading cause of death by infectious disease, with two million deaths annually. For Mtb to thrive within the host, the bacterium must obtain nutrients, including carbon sources which are essential for growth. Mtb can use four primary carbon sources to meet its needs for carbon utilization. Mtb primarily resides within the phagosome of host macrophages and must acquire carbon sources from the macrophage while in this niche. While in this compartment, Mtb also experiences a wide variety of stresses including reactive nitrogen species (RNS) stress. Previous work has shown that in vitro exposure of Mtb to nitric oxide (NO) leads to the nitrosylation of proteins that are essential for glycolysis. Additional preliminary data from our lab shows that either exposing Mtb transposon libraries to NO in vitro leads to an increased importance of fatty acid degradation and decreased reliance on glycolytic pathways during NO exposure. This has led us to hypothesize that exposure to RNS stress leads to changes in the use of carbon by Mtb. To begin to identify how RNS stress effects carbon utilization, Aim 1 will utilize a library of strains that are unable to either utilize or acquire each of the carbon sources. This library will be grown in the presence of single carbon sources and RNS, and growth of each strain will be monitored to determine how the RNS stress affects the ability of each mutant to grow on each carbon source. In Aim 2, this library will be used to infect macrophages and mice that are either wildtype or lack the ability to induce NO expression. These studies will allow us to determine how actual infection conditions affect the ability of Mtb to use various carbon sources. Finally, Aim 3 will focus on identifying the mechanisms by which RNS stress leads to changes in carbon usage by Mtb. These studies will provide important data on how Mtb utilizes carbon under stress conditions and the mechanisms which allow for changes in carbon utilization in vivo.