Activation of human TLR4 by endotoxin binding to MD-2

描述(由申请人提供)：这份为期五年的建议书旨在促进免疫学和传染病领域的学术临床医生研究人员的职业生涯。候选人将完成传染病方面的奖学金培训，并被任命为埃默里大学医学院传染病学部医学系的教员。她的职业发展将由著名医学教授、微生物学和免疫学教授、流行病学教授和传染病科主任大卫·S·斯蒂芬斯博士指导。这项研究计划将在斯蒂芬斯博士的实验室进行，该实验室在微生物发病机制和分子遗传学方面有着长期和成功的记录。 Toll样受体4(TLR4)及其辅助蛋白MD-2和内毒素在脑膜炎球菌和其他革兰氏阴性细菌引起的脓毒症中引发了大部分炎症反应。实验室以前的工作已经确定脑膜炎双球菌KDO2-脂质A在激活TLR4/MD-2受体复合体中起重要作用。假设MD-2是TLR4激活的特异性决定因素，KDOZ-lide A内毒素结构对于直接与MD-2结合至关重要。KDO在与MD-2结合中的重要性，与MD-2结合的其他内毒素结构要求以及TLR4的激活将被研究。具体目标1：使用基因和生物化学定义的脑膜炎球菌脂低聚糖，确定与人类适配蛋白MD-2相互作用所需的脑膜炎球菌KDO2-脂类A结构。具体目标2：通过辅助蛋白MD-2确定TLR4细胞外激活所需的一般内毒素结构。意义重大。了解MD-2在内毒素激活TLR4中的作用可能会影响改变炎症免疫反应的治疗干预。这项提案将确定MD-2最有效识别并提交给TLR4的细菌内毒素成分。其他疾病(如动脉粥样硬化、炎症性肠病和哮喘)的研究也可能受益于这项工作，这些疾病的炎性成分是由TLR4和MD-2的激活介导的。

DESCRIPTION (provided by applicant): This five-year proposal is designed to promote a career as an academic clinician investigator in the fields of immunology and infectious diseases. The candidate will complete fellowship training in infectious diseases and be appointed to the faculty of the Emory University School of Medicine, Department of Medicine, Division of Infectious Diseases. Her career development will be mentored by Dr. David S. Stephens, Distinguished Professor of Medicine, and Professor of Microbiology and Immunology, and Epidemiology, and Director Division of Infectious Diseases. This research plan will be conducted in Dr. Stephens' laboratory which has a long and successful track record in microbial pathogenesis and molecular genetics. The Toll-like receptor 4 (TLR4), together with its accessory protein MD-2, and endotoxin are responsible for initiating much of the inflammatory response in sepsis caused by meningococci and other gram-negative bacteria. Previous work in the laboratory has identified an important role for meningococcal KDO2-lipid A in activation of the TLR4/MD-2 receptor complex. The hypothesis is that MD-2 is a specific determinant of TLR4 activation and that the KDOz-lipid A endotoxin structure is critically important for direct binding to MD-2. The importance of KDO in binding to MD-2, other endotoxin structural requirements for binding to MD-2 and the activation of TLR4 will be investigated. Specific Aim 1: Determine the meningococcal KDO2-lipid A structure required for interaction with the human adaptor protein MD-2 using genetically and biochemically defined meningococcal lipooligosaccharides. Specific Aim 2: Determine the general endotoxin structure required for extracellular activation of TLR4 via the accessory protein MD-2. Significance. Understanding the role of MD-2 in TLR4 activation by endotoxin may impact therapeutic interventions that modify the inflammatory immune response. This proposal will identify the components of bacterial endotoxin which are most efficiently recognized by MD-2 and presented to TLR4. The study of other diseases (e.g. atherosclerosis, inflammatory bowel disease, and asthma) with inflammatory components which are mediated by the activation of TLR4 and MD-2 may also benefit from this work.