MOBILIZATION AND DELIVERY OF LIPOOLIGOSACCHARIDES TO HOST TARGETS

脂寡糖的动员和递送至宿主靶标

• 批准号: 6653280
• 负责人: JERROLD P WEISS
• 金额: $ 12.95万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6653280
• 关键词: Neisseria meningitidis; bactericidal immunity; clinical research; endotoxins; glycolipids; host organism interaction; human subject; laboratory rabbit; lipid biosynthesis; lipid transport; membrane biogenesis; microorganism metabolism; neutrophil; vascular endothelium

Host responses to lipopolysaccharides (LPS) or lipooligosaccharides (LOS) of Gram-negative bacteria (GNB) are believed to play a major role in defense against many invasive GNB infections. These normally protective responses can also cause life-threatening systematic inflammatory disorders when inadequately controlled. This is dramatically illustrated in fulminant meningococcal septicemia, an extreme acute disease that appears linked to the accumulation of extraordinary high levels of LOS. The broad long-term objectives of this project are to better understand the molecular determinants of endotoxin mobilization and of its interaction with defined host targets. A major focus will be on the biogenesis and biological properties of released bacterial membrane blebs, believed to represent an important of disseminated endotoxin in vivo and in a particularly prominent feature of growing N. meningitidis in vitro. Our specific aims are to: I) Determine the effect of interaction of N. meningitidis with components of intravascular host defenses on the synthesis and mobilization of meningococcal LOS; II) Characterize the molecular determinants of delivery of purified LOS, membrane blebs and intact bacteria to polymorphonuclear leukocytes (PMN) and endothelial cells; and III) Compare the susceptibility of LOS presented in the forms of aggregates of purified LOS, membrane blebs and intact bacteria to host-mediated clearance and degradations. We will employ several experimental approaches to quantitatively analyze the metabolism and interactions of meningococcal LOS including define bacterial mutants to permit selective radiolabeling of bacterial (glyco)lipids, TLC/image analysis, HPLC, GC-MS and MALTI-TOF, purified endotoxin-binding proteins and neutralizing antibodies, and affinity purification to search for novel mediators of bacterial membrane bled-host interactions. We will draw heavily on collaborating investigators in this program who provide expertise and tools to study in an unusually systematic and controlled fashion the dynamics of meningococcal (endotoxin)-host interactions. These studies are likely to provide new insights concerning two fundamental questions: 1) What controls the mobilization of endo during the mobilization of endotoxin during bacterial interaction with the host? 2) How do the unique physical characteristics meningococcal LOS and of cell-free LOS-containing membrane from fragments affect the interaction of endotoxin with host machinery that mediate either pro- or anti- inflammatory responses?

宿主对革兰氏阴性菌 (GNB) 的脂多糖 (LPS) 或脂寡糖 (LOS) 的反应被认为在防御许多侵袭性 GNB 感染中发挥着重要作用。如果控制不当，这些通常的保护性反应也可能导致危及生命的系统性炎症性疾病。暴发性脑膜炎球菌败血症就充分说明了这一点，这是一种极端急性疾病，似乎与异常高水平的 LOS 积累有关。该项目的广泛长期目标是更好地了解内毒素动员的分子决定因素及其与确定的宿主靶标的相互作用。主要焦点将是释放的细菌膜泡的生物发生和生物学特性，据信这代表了体内传播内毒素的重要特征，也是脑膜炎奈瑟氏球菌体外生长的一个特别突出的特征。我们的具体目标是： I) 确定脑膜炎奈瑟菌与血管内宿主防御成分的相互作用对脑膜炎球菌 LOS 的合成和动员的影响； II) 表征将纯化的 LOS、膜泡和完整细菌递送至多形核白细胞 (PMN) 和内皮细胞的分子决定因素； III) 比较以纯化 LOS、膜泡和完整细菌的聚集体形式呈现的 LOS 对宿主介导的清除和降解的敏感性。我们将采用多种实验方法来定量分析脑膜炎球菌 LOS 的代谢和相互作用，包括定义细菌突变体以允许选择性放射性标记细菌（糖）脂质、TLC/图像分析、HPLC、GC-MS 和 MALTI-TOF、纯化内毒素结合蛋白质和中和抗体，以及亲和纯化，以寻找细菌膜出血-宿主相互作用的新介质。我们将在该计划中大力利用合作研究人员，他们提供专业知识和工具，以异常系统和受控的方式研究脑膜炎球菌（内毒素）与宿主相互作用的动态。这些研究可能就两个基本问题提供新的见解：1）在细菌与宿主相互作用过程中内毒素的动员过程中，是什么控制着endo的动员？ 2) 脑膜炎球菌 LOS 和碎片中含有 LOS 的无细胞膜的独特物理特性如何影响内毒素与介导促炎或抗炎反应的宿主机制的相互作用？