Methylglyoxal-induced macrophage metabolic dysregulation in sepsis

脓毒症是一种对感染的异常免疫反应，每年约有100万例 美国的总死亡率为~20%-30%，在败血症休克1-3%的情况下增加到~40%-50%。脓毒症是 特点是应激性高血糖，线粒体功能障碍，持续的，强烈的氧化 条件。虽然脓毒症是一种复杂的疾病，涉及许多不同的细胞和组织，但更好的 了解巨噬细胞在脓毒症中的作用可能会揭示新的治疗靶点。MF展品 体内外动态、刺激性功能可塑性及其活性的临界变化 在脓毒症期间被认为是由细菌产物(例如，脂多糖；脂多糖)和 促炎细胞因子(例如，干扰素-g；干扰素-g)，将MF重新编程为高度促炎， 激活“或”M1“表现型。这些信号通路也稳定了转录因子缺氧- 诱导因子-1a(HIF-1a)7，8.HIF-1a是糖酵解基因的主要调节者9，促进深刻的 代谢开关，10-12年的“华宝效应”修订版，在以糖酵解和线粒体为主的M1 MF中 氧化磷酸化基本上是不存在的，即使在氧气存在的情况下也是如此。我们认为这种新陈代谢 在脓毒症中，通过促进促炎细胞因子的产生，调节失调是炎症反应的基础。 由于组织暴露于损害M1 MF依赖的活性氧物种(ROS)、蛋白酶和 生物活性脂类。虽然细胞因子和ROS已被广泛研究，但对其作用知之甚少 甲基乙二醛(MG)，一种高活性的二羰基副产物，可在细胞内积累 磷酸三糖异构酶(TPI)14，15介导的糖酵解反应。 败血症休克患者已被确定为与疾病严重程度相关的生物标志物21。我们有 报道了在体外，MG在脂多糖和干扰素-g的刺激下，在M1-MF中聚集，并导致 在体外和内毒素小鼠肺内与宿主蛋白形成共价“MG加合物”17。我们的 中心假设是MG，一种相对短暂但高度活跃的代谢物，产生于对 内毒素+干扰素-g激活MF，引导脓毒症炎性M1 MF分化，及其抑制策略 MG的产生或活性将阻止这种分化，从而减少由MF引起的炎症。我们的 科学前提是，可以利用选择性靶向MG积聚来缓解脓毒症- 相关的组织损伤和死亡。我们认为，内毒素+干扰素-g诱导的HIF-1a稳定启动 脓毒症通过增加糖酵解、MG蓄积、MG介导促进M1-MF分化 线粒体蛋白质糖基化，破坏线粒体功能。具体目标1将描述 MG在MF中积聚破坏线粒体功能的机制，目标2将研究 代谢信号通路对MG蓄积的影响，Aim 3将测试MG-1的治疗效果。 降解酶，以减轻内毒素和细菌败血症。

Sepsis is an aberrant immune response to infection1 with approximately one million cases/year in the U.S.A. and an overall fatality rate of ~20-30%, increasing to ~40-50% in the case of septic shock1-3. Sepsis is characterized by stress hyperglycemia4, mitochondrial dysfunction5, and persistent, strongly oxidizing conditions. Although sepsis is a complex disease involving many different cells and tissues, a better understanding of the role of macrophages (Mf) during sepsis may reveal new therapeutic targets. Mf exhibit dynamic, stimulus-dependent functional plasticity in vitro and in vivo and critical changes to their activities during sepsis are thought to be initiated by bacterial products (e.g., lipopolysaccharide; LPS) and proinflammatory cytokines (e.g., interferon-g; IFN-g) that reprogram Mf to a highly proinflammatory, “classically activated” or “M1” phenotyperev. in 6. These signaling pathways also stabilize the transcription factor Hypoxia- Inducing Factor-1a (HIF-1a)7,8. HIF-1a is a master regulator of glycolytic genes9, facilitating a profound “metabolic switch,” the “Warburg effect” rev. in 10-12, in M1 Mf in which glycolysis predominates and mitochondrial oxidative phosphorylation is essentially absent, even when oxygen is present. We propose that this metabolic dysregulation underlies inflammation during sepsis, by driving production of proinflammatory cytokines as well as exposure of tissues to damaging M1 Mf-dependent reactive oxygen species (ROS), proteases, and bioactive lipids. While cytokines and ROS have been extensively studied, less is known about the role of methylglyoxal (MG), a highly reactive, dicarbonyl byproduct that can accumulate intracellularly during the glycolytic reaction mediated by triose phosphate isomerase (TPI)14,15. Significantly, elevated MG in sera of septic shock patients has been identified as a biomarker that correlates with disease severity21. We have reported that MG accumulates in M1 Mf upon stimulation with LPS and IFN-g in vitro, and results in the formation of covalent “MG-adducts” with host proteins both in vitro and in the lungs of endotoxic mice17. Our central hypothesis is that MG, a relatively short-lived, but highly reactive metabolite generated in response to LPS+IFN-g activation of Mf, directs inflammatory M1 Mf differentiation in sepsis, and that strategies that inhibit MG production or activity will prevent such differentiation, and thereby reduce Mf-directed inflammation. Our scientific premise is that selective targeting of MG accumulation can be capitalized upon to mitigate sepsis- associated tissue damage and death. We propose that LPS + IFN-g-induced stabilization of HIF-1a initiates sepsis by promoting M1 Mf differentiation through increased glycolysis, MG accumulation, MG-mediated glycation of mitochondrial proteins that disrupts mitochondrial function. Specific Aim 1 will characterize mechanisms by which MG accumulation in Mf disrupts mitochondrial function, Aim 2 will examine the role of metabolic signaling pathways on MG accumulation, and Aim 3 will test the therapeutic efficacy of MG- degrading enzymes to mitigate endotoxicity and bacterial sepsis.