Role of metabolic Me-macrophages in the pathogenesis of tuberculosis during diabetes

摘要 2型糖尿病(T2D)大流行是公认的结核病复发风险和挑战 (结核病)控制。然而，识别和预防数百万有患结核病风险的T2D患者的战略 需要对潜在的机制有所了解，而人们对此知之甚少。分枝杆菌 结核杆菌(MTB)是一种细胞内病原体，可在巨噬细胞内复制或被杀死(MΦS)。这个 结核分枝杆菌在MΦS体内存活的能力在很大程度上取决于其逃避含有结核分枝杆菌的融合的能力 带有溶酶体的吞噬小体或自噬小体(自噬途径)。然而，体外研究表明， 通过适当的MΦ激活(如用干扰素-γ)，细胞内的Mtb靶向于吞噬溶酶体或自身... 吞噬酶体能更有效地杀伤、消化和将抗原呈递给T细胞。人M-Φ的研究 表型和功能通常是通过M1和M2范例来概念化的，其中M1具有特征 通过增加促炎细胞因子的产生，而M2具有更多的免疫抑制表型。 我们和其他人使用M1/M2范式来研究结核病的发病机制，M1 MΦS发挥了更好的MTB作用 与更宽松的M2(M1和M2)相比，杀伤力更强。虽然M1-M2 MΦ框架非常有用 为了在体外研究结核病的发病机制，它没有捕捉到影响MΦ的不同环境线索 T2D宿主的可塑性。为了解决这一问题，我们提出了一种研究结核病的体外模型 最近描述的M-Φ表型被极化为“代谢”的T2D患者的发病机制 在高棕榈酸、葡萄糖和胰岛素条件下培养时的表型。我们建议使用以下方法进行研究 代谢MΦS(Me)确定T2D患者代谢环境的改变如何影响 MΦS对Mtb的表型和功能反应(vsM1或M2)。我们的团队是进行这些研究的理想选择： BIR(MPI)住在德克萨斯州-墨西哥边境，在那里她表现出高结核病-T2D发病率，并记录 T2D患者单核细胞及M-ΦS缺陷CJ(MPI)在MΦ应对结核病方面有30年的经验。 我们的顾问开发了Me MΦ模型(LB)，或具有结核病肺部生物学(JT)方面的专业知识。我们的目标是： 目的1.对照培养条件下评价S分化的人骨髓间充质干细胞对结核分枝杆菌的反应 在肺部模拟T2D的条件。 目的2.鉴定正常人与T2D/-TB患者单核细胞来源的Me MΦS的差异。 我们的体外TB-T2D MΦ模型将追溯T2D或TB-T2D患者或动物模型的体内发现， 促进假设的生成和检验。我们对结核病或T2D患者单核细胞的获取将有所帮助 在体外识别在长期暴露于改变后保留的“新陈代谢”或“炎症性”记忆 体内的代谢物。因此，我们的模型将对有效主机的设计产生立竿见影的影响- 定向治疗使人糖尿病MΦS获得最佳的结核分枝杆菌杀伤。

ABSTRACT The type 2 diabetes mellitus (T2D) pandemic is a recognized re-emerging risk and challenge to tuberculosis (TB) control. However, strategies to identify and prevent the millions of T2D patients at risk of developing TB requires an understanding of the underlying mechanisms, which are poorly understood. Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that can replicate or get killed within macrophages (MΦs). The ability of Mtb to survive within MΦs depends largely on its ability to evade fusion of the Mtb-containing phagosomes with lysosomes or auto-phagosomes (autophagy pathway). However, in-vitro studies show that with appropriate MΦ activation (e.g. with IFN-γ), intracellular Mtb is targeted to the phagolysosome or auto- phagolysosome for more effective killing, digestion and antigen presentation to T cells. Studies of human MΦ phenotype and function are often conceptualized through an M1 and M2 paradigm, with the M1 characterized by increased production of pro-inflammatory cytokines, while M2 having more immunosuppressive phenotype. We and others have used the M1/M2 paradigm to study TB pathogenesis, with M1 MΦs exerting better Mtb killing when compared to the more permissive M2 (M1> M2). While the M1-M2 MΦ framework has been useful to study TB pathogenesis in-vitro, it does not capture the different environmental cues that influence MΦ plasticity in the T2D host. We address this gap by proposing the development of an in-vitro model to study TB pathogenesis in T2D patients using a recently described MΦ phenotype that is polarized to a “metabolic” phenotype when cultured under conditions of high palmitate, glucose and insulin. We propose studies using this Metabolic MΦs (Me) to determine how the altered metabolic environment in T2D patients affects the phenotype and functional responses of MΦs to Mtb (vs M1 or M2). Our team is ideal conduct these studies: BIR (MPI) lives in the Texas-Mexico border where she has demonstrated high TB-T2D rates, and documented defects in monocytes and MΦs from T2D patients. CJ (MPI) has 30+ yrs experience in MΦ responses to TB. Our consultants developed the Me MΦ model (LB), or have expertise in TB lung biology (JT). Our Aims are: Aim 1. Evaluate the response to Mtb by human Me MΦs differentiated under controlled culture conditions that simulate T2D in the lungs. Aim 2. Identify differences in the Me MΦs derived from monocytes of healthy vs T2D +/- TB patients. Our in-vitro TB-T2D MΦ model will retro-feed with in-vivo findings in T2D or TB-T2D patients or animal models, facilitating hypothesis generation and testing. Our access to monocytes from patients with TB or T2D will help identify the “metabolic” or “inflammatory” memories in vitro, that are retained after chronic exposure to altered metabolites in-vivo. Thus, our model will have an immediate impact for paving the design of effective host- directed therapies to polarize human diabetic MΦs for optimal Mtb killing.