Hypoxia, tuberculosis, and T cell dysfunction

抽象的。结核分枝杆菌(Mtb)感染后，5%-10%的人出现临床症状 结核病(TB)，大部分在两年内。这导致1000万新结核病病例和150万死亡病例 年。为什么最初控制结核分枝杆菌的人免疫失败并允许复发，目前尚不清楚。风险因素 包括糖尿病、营养不良、酗酒、癌症和吸烟，所有这些都会导致代谢压力。我们的长期合作 目的是了解免疫失败的驱动因素，识别免疫的保护机制。一位少校 知识缺口是指各种新陈代谢损伤如何影响受感染肺的细胞免疫。我们的拱顶 假设在结核病期间，新陈代谢应激源，如肉芽肿缺氧，导致T细胞功能障碍， 降低免疫力，削弱结核分枝杆菌的控制。我们和其他人发现肺结核病患者的T细胞 而长期感染结核分枝杆菌的小鼠功能失调。功能失调的CD8T细胞(如耗尽的CD8T细胞) 由于它们在肿瘤免疫中的作用，已被广泛研究。相比之下，人们对cd4的了解要少得多。 T细胞功能障碍。我们将同时研究CD_4和CD_8 T细胞，重点放在CD_4 T细胞上，因为它们是至关重要的 对结核杆菌的豁免权。我们将使用小鼠结核病模型来研究代谢应激如何影响T细胞功能 并与结核病的发病机制有关。我们策略的一个重要组成部分是比较来自 易患缺氧性肉芽肿的小鼠，其T细胞来自耐药小鼠品系。第一个目标是 “确定代谢紊乱和T细胞功能障碍之间的关系。”T的高分辨率地图 易感和耐药小鼠对结核分枝杆菌的细胞反应将在执行scRNASeq，TCRseq， 常规流式细胞术和MetFlow(用于评估细胞代谢)。我们将确定是否功能失调 在体外和体内，T细胞对结核分枝杆菌的控制不同。其次，我们将“确定低氧对T细胞的影响 对结核分枝杆菌的豁免权。利用缺氧命运报告小鼠，我们将在体内研究缺氧对T细胞功能的影响。 这些研究将与使用体外低氧培养条件的机制研究相结合。我们将建立 低氧、代谢应激和T细胞功能是如何相关的，以及低氧是否不利于保护 结核病期间的T细胞反应。最后，目标3将“评估代谢干预如何改变T细胞功能和结核病 结果。“我们预测，纠正潜在代谢紊乱的药物可以改善T细胞功能和 加强对结核分支杆菌感染的控制。利用低氧小鼠模型，进行原理验证实验 为了确定影响新生血管、靶向代谢或保护线粒体的药物如何影响结核分枝杆菌 体内的遏制。我们的研究将确定低氧和代谢应激如何影响对结核分枝杆菌和结核杆菌的免疫 提供有关CD4免疫失败的原因的见解。由于T细胞在控制结核分枝杆菌感染方面是必不可少的，我们假设 限制T细胞功能障碍或改善其功能的干预措施将加强对结核分枝杆菌的控制。新陈代谢 肿瘤微环境中T细胞的重新编程即将出现。我们的假设包含这样的观点 代谢疗法可以预防或逆转T细胞功能障碍，改善结核病预后。

Abstract. After Mycobacterium tuberculosis (Mtb) infection, 5-10% of people develop clinically evident tuberculosis (TB), most within two years. This leads to 10 million new cases of TB and 1.5 million deaths each year. Why immunity fails and permits recrudescence in people that initially control Mtb is unknown. Risk factors include diabetes, malnutrition, alcoholism, cancer, and smoking, all which cause metabolic stress. Our long-term goal is to understand the drivers of immune failure and identify protective mechanisms of immunity. A major knowledge gap is how various metabolic insults affect cellular immunity in the infected lung. Our over-arching hypothesis is that that during TB, metabolic stressors such as granuloma hypoxia contribute to T cell dysfunction, degrade immunity, and impair Mtb containment. We and others find that T cells from patients with pulmonary TB and chronically Mtb-infected mice are dysfunctional. Dysfunctional CD8 T cells (e.g., exhausted CD8 T cells) have been intensively studied because of their role in tumor immunity. In contrast, far less is known about CD4 T cell dysfunction. We will investigate both CD4 and CD8 T cells and focus on CD4 T cells as they are crucial for immunity to Mtb. We will use the murine TB model to investigate how metabolic stress affects T cell function and contributes to TB pathogenesis. An important component of our strategy is to compare T cells from susceptible mice that develop hypoxic granulomas with T cells from resistant mouse strains. The first aim is to “Determine the relationship between metabolic perturbation and T cell dysfunction.” A high-resolution map of T cell responses to Mtb in susceptible and resistant mice will be assembled after performing scRNASeq, TCRseq, conventional flow cytometry and MetFlow (to assess cell metabolism). We will determine whether dysfunctional T cells differ in their control of Mtb in vitro and in vivo. Secondly, we will “Determine how hypoxia affects T cell immunity against Mtb.” Using hypoxia fate reporter mice, we will study how hypoxia affects T cell function in vivo. These studies will be coupled with mechanistic studies using hypoxic culture conditions in vitro. We will establish how hypoxia, metabolic stress, and T cell function are related, and whether hypoxia is detrimental to protective T cell responses during TB. Finally, Aim 3 will “Assess how metabolic interventions alter T cell function and TB outcome.” We predict that drugs that correct underlying metabolic perturbations can improve T cell function and enhance control of Mtb infection. Using the hypoxic mouse models, proof-of-principle experiments will be done to determine how drugs that affect neovascularization, target metabolism, or protect mitochondria, affect Mtb containment in vivo. Our studies will determine how hypoxia and metabolic stress affect immunity to Mtb and provide insight into why CD4 immunity fails. As T cells are essential in containing Mtb infection, we hypothesize that interventions to limit T cell dysfunction or improve their function will augment Mtb containment. Metabolic reprogramming of T cells in the tumor microenvironment is on the horizon. Our hypothesis embraces the idea that metabolic therapeutics could prevent or reverse T cell dysfunction and improve TB outcome.