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

基本信息

批准号：
10356878
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
项目类别：
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/10356878
关键词：
Adaptive Immune System Affect Amino Acids Antigen Presentation Bacillus Bacteria Bacterial Infections 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 Immune Immune response Immunologic Receptors Immunologic Surveillance Infection Inflammasome Inflammation Inflammatory Inflammatory Response Innate Immune Response Innate Immune System Interleukin-18 Knockout Mice Ligands Lipids 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 inhibitor knock-down macrophage mouse model receptor recruit response sugar

项目摘要

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.

抽象的吞噬细胞的免疫监测通过内部化细菌和通过酶促降解的过程杀死它们。降解还释放激活的细菌分子天生的免疫受体和抗原最终向适应性免疫系统呈现编排对微生物的总体免疫响应。革兰氏阳性细菌的细胞壁，金黄色葡萄球菌主要组成的辣椒粉，氨基酸糖糖聚合物。我们最近证明了单体糖N-乙酰葡萄糖胺在肽聚糖降解是炎症的。 N-乙酰葡萄糖与糖酵解酶相互作用己糖酶，抑制其功能。结果，己糖激酶与线粒体外部的互动膜受到破坏，这种解离会启动一个信号级联，负责组装多蛋白NLRP3炎性体复合物激活蛋白酶caspase-1。 cas 1负责裂解和激活几种关键炎症细胞因子，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适应了正常的糖酵解调节，以将细菌糖的绝对高水平感知为危险。为了逃避免疫监视，细菌修改其胡椒狗层以抵抗降解吞噬细胞并限制了包括N-乙酰葡萄糖在内的先天炎症信号的可用性。撞击己酰胺的N-乙酰葡萄糖的量和糖酵解的量将取决于转运穿过整个吞噬膜进入细胞质。初步证据表明IL-的数量吞噬细胞产生的1B，特别是针对胡椒糖的响应，取决于糖运输的糖家族。此外，我们已经生成了一个缺陷的鼠标模型三种由吞噬细胞表达的己糖苷酶，观察到对糖酵解和糖酵解的不同影响炎症反应。该建议旨在定义由对革兰氏阳性细菌的炎症反应中的吞噬细胞，也表征了薄荷糖衍生的N-乙酰葡萄糖对代谢和代谢的运输和影响吞噬细胞的炎症反应。我们假设炎症的总体程度革兰氏阳性细菌受到N-乙酰葡萄糖产生的数量和可用性的影响在细菌性肽聚糖降解期间，部分归因于N-乙酰葡萄糖抑制糖酵解的抑制代谢。