Mechanisms of peptidoglycan-induced modulation of metabolic and inflammatory responses to bacteria

肽聚糖诱导的细菌代谢和炎症反应调节机制

• 批准号: 10574547
• 负责人: Andrea Jean Wolf
• 金额: $ 41.75万
• 依托单位: CEDARS-SINAI MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-10 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10574547
• 关键词: Adaptive Immune System; Affect; Amino Acids; Antigen Presentation; Bacillus; Bacteria; Bacterial Infections; Binding; Bone Marrow; CASP1 gene; Cell Wall; Cells; Cellular Structures; Complex; Cytosol; Dendritic Cells; Dissociation; Enzymes; Exposure to; Family; Glycolysis; Glycolysis Inhibition; Gram-Positive Bacteria; Gram-Positive Bacterial Infections; Hexokinase 2; Host Defense; IL18 gene; Immune; Immune Evasion; Immune response; Immunologic Receptors; Immunologic Surveillance; Infection; Infection Control; Inflammasome; Inflammation; Inflammatory; Inflammatory Response; Innate Immune Response; Innate Immune System; Knockout Mice; Ligands; Lipids; Macrophage; Membrane; Metabolic; Metabolism; Microbe; Mitochondria; Mus; Myelogenous; Myeloid Cells; Outcome; Outer Mitochondrial Membrane; Pathology; Pathway interactions; Peptide Hydrolases; Peptidoglycan; Phagocytes; Phagosomes; Phenotype; Play; Polymers; Process; Production; Proteins; Regulation; Research; Resistance; Role; SLC2A1 gene; Signal Transduction; Small Interfering RNA; Staphylococcus aureus; Therapeutic; Tissues; Toll-like receptors; Vertebral column; adaptive immune response; crosslink; cytokine; design; experimental study; hexokinase; in vivo; inflammatory milieu; inflammatory modulation; inhibitor; knock-down; monomer; mouse model; receptor; recruit; response; sugar

ABSTRACT Immune surveillance by phagocytic cells plays a vital role in controlling infections by internalize bacteria and kill them by a process of enzymatic degradation. Degradation also releases bacterial molecules that activate innate immune receptors and antigens for presentation to the adaptive immune system ultimately orchestrating the overall immune response to a microbe. The cell wall of gram-positive bacteria, like Staphylococcus aureus, is predominantly composed peptidoglycan, an amino acid-crosslinked sugar polymer. We recently demonstrated that the monomeric sugar, n-acetylglucosamine, released during peptidoglycan degradation, is inflammatory. N-acetylglucosamine interacts with the glycolytic enzyme hexokinase, inhibiting its function. As a consequence, hexokinase’s interaction with the mitochondrial outer membrane is disrupted and this dissociation initiates a signaling cascade responsible for assembly of the multi-protein NLRP3 inflammasome complex necessary for activation of the protease caspase-1. Caspase- 1 is responsible for the cleavage and activation of several key inflammatory cytokines, including IL-1b and IL-18, important for inflammatory cell recruitment and activation. Our results suggest that phagocytic cells have adapted their normal glycolytic regulation to sense abnormally high levels of a bacterial sugar as danger. To evade immune surveillance, bacteria modify their peptidoglycan layer to resist degradation by phagocytic cells and limiting the availability of innate inflammatory signals, including n-acetylglucosamine. The amount of n-acetylglucosamine impacting hexokinase function and glycolysis will depend on transport across the phagosomal membrane into the cytosol. Preliminary evidence suggests that the amount of IL- 1b produced by phagocytic cells, specifically in response to peptidoglycan, is dependent on the function of the GLUT family of sugar transports. In addition, we have generated a mouse model deficient for one of the three hexokinases expressed by phagocytic cells and observed differential impacts on glycolysis and inflammatory responses. This proposal aims to define the roles of the three hexokinases expressed by phagocytic cell in the inflammatory response to gram-positive bacteria peptidoglycan, as well characterize the transport and impact of peptidoglycan-derived n-acetylglucosamine on the metabolism and inflammatory responses of phagocytic cells. We hypothesize that the overall degree of inflammation induced by gram-positive bacteria is impacted by the amount and availability of n-acetylglucosamine generating during bacterial peptidoglycan degradation due in part to n-acetylglucosamine’s inhibition of glycolytic metabolism.

摘要 吞噬细胞的免疫监测在控制细菌内化和感染方面发挥着至关重要的作用 通过酶降解过程杀死它们。降解还会释放出激活细菌分子的 先天免疫受体和抗原最终呈现给适应性免疫系统 协调对微生物的整体免疫反应。革兰氏阳性细菌的细胞壁，比如 金黄色葡萄球菌主要由肽聚糖组成，这是一种氨基酸交联糖。 聚合物。我们最近证明了单体糖，N-乙酰氨基葡萄糖，在 肽聚糖的降解，是炎症性的。N-乙酰氨基葡萄糖与糖酵解酶相互作用 己糖激酶，抑制其功能。因此，己糖激酶与线粒体外部的相互作用 膜被破坏，这种解离启动了一个信号级联，负责组装 激活caspase-1所必需的多蛋白NLRP3炎症体复合体。半胱氨酸酶- 1负责裂解和激活几个关键的炎性细胞因子，包括IL-1b和 IL-18，对炎症细胞募集和激活很重要。我们的结果表明吞噬细胞 已经调整了它们正常的糖酵解调节来感觉到细菌糖的异常高水平 危险。为了躲避免疫监视，细菌通过修饰它们的肽聚糖层来抵抗降解 吞噬细胞，限制包括N-乙酰氨基葡萄糖在内的先天炎症信号的可获得性。 影响己糖激酶功能和糖酵解的N-乙酰氨基葡萄糖的量将取决于运输 穿过吞噬体膜进入胞浆。初步证据表明，白介素量- 吞噬细胞产生的1B，特别是对肽聚糖的反应，依赖于 糖运输的供过于求家族。此外，我们还生成了一个不适合其中一个的小鼠模型 吞噬细胞表达的三种己糖激动酶及其对糖酵解和蛋白质合成的影响 炎症反应。该提案旨在定义三种己糖激酶酶的作用 吞噬细胞在炎症反应中对革兰氏阳性菌肽聚糖的影响 肽聚糖衍生N-乙酰氨基葡萄糖的转运及其对代谢和代谢的影响 吞噬细胞的炎症反应。我们假设炎症的总体程度导致 革兰氏阳性菌产生N-乙酰氨基葡萄糖的数量和可获得性影响 细菌肽聚糖降解过程中N-乙酰氨基葡萄糖抑制糖酵解作用 新陈代谢。