Glutamine metabolism in tuberculosis

摘要 结核分枝杆菌（Mtb）仍然是最成功的人类病原体，在2010年造成150万人死亡。 2018.越来越多的证据表明，结核分枝杆菌的生存能力，持续存在和导致疾病的主要原因是 其破坏宿主对感染的免疫和抗菌反应的能力。的最新进展 免疫代谢研究表明，代谢转变为糖酵解，即瓦尔堡效应，对于 免疫细胞的激活和效应功能以控制感染。然而，研究有限， 感染巨噬细胞代谢状态的改变如何影响先天性巨噬细胞的激活和功能， 获得性免疫我们的实验室和其他实验室已经描述了多种免疫代谢变化的特征， 发现代谢重构对HIF-1介导的瓦尔堡效应是一种普遍反应 结核分枝杆菌感染通过详细分析结核分枝杆菌感染的巨噬细胞的免疫代谢特性， 转录组学、代谢组学和治疗化合物治疗，我们发现了M1的新证据 在巨噬细胞感染的初始阶段的极化伴随着谷氨酰胺摄取的增加， 新陈代谢.鉴于谷氨酰胺代谢的多效性作用，包括TCA的回补反应， 循环，氧化还原稳态，核苷酸和NADPH的合成，我们的研究结果表明， 谷氨酰胺摄取和代谢构成M1代谢重构程序的组成部分 巨噬细胞基于这些观察结果，我们假设谷氨酰胺作为重要的碳， 氮源的免疫细胞和它的可用性和代谢是必不可少的激活和 宿主对Mtb感染的先天性和适应性免疫功能。为了验证我们的假设，我们提出两个 具体目标。在目标1中，我们将定义谷氨酰胺在介导M1代谢和生理中的作用。 巨噬细胞我们还将破译谷氨酰胺作为碳源和氮源的代谢足迹， M1极化使用稳定同位素示踪代谢组学与13 C（1- 13 C和5- 13 C）谷氨酰胺和15 N（α-N， 和g-N）谷氨酰胺。在目标2中，我们将描述谷氨酰胺代谢在介导活化中的作用。 和功能的先天性和适应性免疫细胞使用治疗验证的小分子抑制剂， 氨解途径。我们还将评估是否补充谷氨酰胺结核分枝杆菌感染的动物 可以作为辅助宿主导向治疗（HDTs）的可行策略，以增强宿主的抗菌反应 免疫细胞在结核病小鼠模型中对抗结核分枝杆菌感染。通过阐明谷氨酰胺代谢的影响 对宿主免疫细胞功能特性的影响，本研究将建立一个新的结核病免疫代谢方面 research.这项研究的结果将为开发新的辅助HDTs开辟新的途径， 谷氨酰胺代谢来治疗结核病。

Abstract Mycobacterium tuberculosis (Mtb) remains the most successful human pathogen, causing 1.5 million deaths in 2018. Accumulating evidence suggests that Mtb’s ability to survive, persist and cause disease is largely due to its ability to subvert the host immune and antimicrobial response to infection. Recent advances in immunometabolism studies have shown that a metabolic shift to glycolysis, aka the Warburg effect, is critical for the activation and effector functions of immune cells to control the infection. However, there are limited studies on how the change of metabolic state of infected macrophages affects the activation and function of innate and adaptive immunity in TB. Our laboratory and others have characterized the immunometabolic changes in multiple model of TB and found that the metabolic remodeling to the HIF-1-mediated Warburg effect is a general response to Mtb infection. Through detailed analysis of immunometabolic properties of Mtb-infected macrophages using transcriptomics, metabolomics and therapeutic compound treatment, we discovered novel evidence that M1 polarization at initial stage of macrophage infection is accompanied by increased glutamine uptake and metabolism. Given the pleiotropic roles of glutamine metabolism, including anaplerotic reactions from the TCA cycle, redox homeostasis, and synthesis of nucleotides and NADPH, findings from our studies suggest that glutamine uptake and metabolism constitute an integral component of metabolic remodeling program of M1 macrophages. Based on these observations, we hypothesize that glutamine functions as important carbon and nitrogen source for immune cells and that its availability and metabolism are essential for the activation and function of host innate and adaptive immunity against Mtb infection. To test our hypothesis, we propose two Specific Aims. In Aim 1, we will define the role of glutamine in mediating the metabolism and physiology of M1 macrophages. We will also decipher the metabolic footprints of glutamine as carbon and nitrogen source during M1 polarization using stable isotope tracing metabolomics with 13C (1-13C and 5-13C) glutamine and 15N (a-N, and g-N) glutamine. In Aim 2, we will characterize the role of glutamine metabolism in mediating the activation and functions of innate and adaptive immune cells using therapeutically validated small molecule inhibitor for glutaminolysis pathway. We will also evaluate whether supplementation of glutamine to Mtb-infected animals can serve as a viable strategy of adjunct host directed therapies (HDTs) to boost antimicrobial response of host immune cells against Mtb infection in a mouse model of TB. By elucidating the effects of glutamine metabolism on the functional property of host immune cells, this study will establish a novel immunometabolic aspect of TB research. Outcomes of this study will open new avenues for the development of new adjunct HDTs by targeting glutamine metabolism to treat TB worldwide.