MICROBIAL LIGAND RECOGNITION BY INNATE IMMUNE SENSORS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 背景 我们依靠先天免疫系统作为抵御入侵病原体的第一道防线。这种免疫反应严重依赖Toll样受体(TLRs)。每个TLR识别特定病原体特有的不同分子模式，如细菌细胞壁成分、细菌细丝或病毒DNA和RNA。在配体结合时，TLRs向细胞核传递信号，导致致炎化合物的产生。其中包括抗微生物细胞因子，以及招募适应性免疫系统的化合物，后者建立对特定病原体的长期免疫力。 目标 我们将分别确定人类TLR5、TLR8或TLR9与其配体细菌鞭毛蛋白、单链RNA或CpG DNA的复合体的三维结构。这些复合体的结构将为病原体识别和促炎信号的产生提供关键的分子基础。 我们将以毫克量表达TLR5/8/9的胞外结构域，并将它们与各自的配体形成络合物。我们将通过X射线结晶学来确定这些配合物的三维结构。为了测试我们关于TLR功能的基于结构的假设，我们将测量从结构预测的干扰配体结合或信号生成的工程突变对免疫信号的影响。我们提出了一种寻找高亲和力TLR配体或激动剂的策略。 相关性 我们的工作将揭示病原体识别如何转化为免疫反应信号的分子基础。我们的结构将指导设计合成TLR激动剂的努力，这些激动剂可以用作新型疫苗佐剂，或作为免疫调节疗法。这种疗法将为预防和治疗传染病提供一种强有力的新手段。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Background We rely on our innate immune system as the first line of defense response against invading pathogens. This immune response is critically dependent on the Toll-like receptors (TLRs). Each TLR recognizes a different molecular pattern that is characteristic of specific pathogens, such as bacterial cell wall components, bacterial filaments, or viral DNA and RNA. Upon ligand binding, TLRs transmit a signal to the nucleus that leads to the production of proinflammatory compounds. These include antimicrobial cytokines, and compounds that recruit the adaptive immune system, which establishes long-term immunity to specific pathogens. Objectives We will determine three-dimensional structures of human TLR5, TLR8 or TLR9, in complex with their ligands¿¿" bacterial flagellin, single-stranded RNA or CpG DNA, respectively. The structures of these complexes will provide critical insight into the molecular basis of pathogen recognition and proinflammatory signal generation. We will express the ectodomains of TLR5/8/9 in milligram quantities and crystallize them in complex with their respective ligands. We will determine three-dimensional structures of the complexes by X-ray crystallography. To test our structure-based hypotheses on TLR function, we will measure the effect on immune signaling of engineered mutations that are predicted from the structures to interfere with ligand binding or signal generation. We propose a strategy to seek high-affinity TLR ligands, or agonists. Relevance Our work will reveal the molecular basis for how pathogen recognition is translated into an immune response signal. Our structures will guide efforts to design synthetic TLR agonists, which could serve as novel vaccine adjuvants, or as immunomodulatory therapeutics. Such therapeutics would provide a powerful new means to prevent and treat infectious diseases.