Role of chemokine monomer-dimer equilibrium in innate immunity and inflammation

描述(申请人提供)：趋化因子CXCL8(也称为白介素8)通过将中性粒细胞从血液中招募到因细菌感染等侮辱而受损的组织中，在先天免疫和炎症中发挥关键作用。我们的长期目标是了解CXCL8功能的分子机制，从而为新的抗炎治疗奠定基础。CXCL8通过与中性粒细胞上的G蛋白偶联受体(GPCRs)以及细胞外基质和内皮上的糖胺多聚糖(GAG)结合来发挥作用。趋化因子的一个基本属性是能够以单体和晚餐的形式可逆地存在。因此，了解CXCL8单体和二聚体与GPCRs和GAG的结合对于了解中性粒细胞在体内的募集至关重要。我们的假设是，CXCL8的四种形式之间的动态平衡，即溶液中的单体和晚餐以及与GAP结合的单体和晚餐之间的动态平衡，调节着体内中性粒细胞的招募。在这个项目中，我们将通过表征捕获的单体和二聚体以及与GPCRs或GAG结合减少的天然CXCL8的突变体，以及显示二聚化能力降低的天然CXCL8的突变体来验证我们的假设。我们将在动物模型中确定单体-二聚体的平衡，以及单体和二聚体对GAG和GPCRs的结合作用，调节体内CXCL8的功能(目标1)。我们将确定单体和晚餐是否会引发类似的信号事件(但强度不同)，还是会引发独特的信号事件(目标2)。最后，通过确定单体和二聚体如何结合GAG，我们将更好地定义单体和二聚体在溶液中和结合到GAG上的分布(目标3)。我们研究设计的创新包括结合使用生物物理、体外细胞和体内动物研究；新试剂(捕获的单体和二聚体)；以及一种新的微流体设备技术来测量趋化性。摘要：炎症在许多血管和过敏性疾病以及细菌和病毒感染的病理中起着核心作用。这些疾病会导致严重的身体虚弱和死亡，并造成高昂的经济成本。目前的药物要么是治疗症状而不是疾病，要么是非特异性地抑制免疫和炎症反应。因此，基于趋化因子功能设计的高度特异性的新药应该能为这些疾病提供更好的治疗方法。

DESCRIPTION (provided by applicant): The chemokine CXCL8 (also known as interleukin-8) plays a key role in innate immunity and inflammation by recruiting neutrophils from the bloodstream to tissue damaged by such insults as bacterial infection. Our long-term goal is to understand the molecular mechanisms of CXCL8 function, and so lay the foundation for new anti-inflammatory treatments. CXCL8 exerts its function by binding to G protein-coupled receptors (GPCRs) on neutrophils, and to glycosaminoglycans (GAGs) on the extracellular matrix and endothelium. A fundamental property of chemokines is the ability to exist reversibly as both monomers and dinners. Therefore, knowledge of CXCL8 monomer and dimer binding to GPCRs and GAGs is critical for understanding in vivo neutrophil recruitment. Our hypothesis is that a dynamic equilibrium among four CXCL8 forms, monomers and dinners in solution and monomers and dinners bound to GAG, regulates in vivo neutrophil recruitment. In this project, we will test our hypothesis by characterizing mutants of trapped monomers and dimers and of native CXCL8 that show reduced binding to either GPCRs or GAGs, and mutants of native CXCL8 that show reduced dimerization potency. We will determine how monomer-dimer equilibrium, and the binding interactions of monomers and dimers for GAGs and GPCRs, regulate in vivo CXCL8 function in animal models (Aim 1). We will determine whether monomers and dinners elicit similar signaling events (but with different potencies), or elicit unique signaling events (Aim 2). Finally, by determining how monomers and dimers bind GAGs, we will better define the distribution of monomers and dimers in solution and bound to GAGs (Aim 3). Innovations in our research design include using a combination of biophysical, in vitro cell-based, and in vivo animal-based studies; novel reagents (trapped monomers and dimers); and a novel microfluid device technology to measure chemotaxis. Lay Abstract: Inflammation plays a central role in the pathology of many vascular and allergic diseases, and of bacterial and viral infections. These diseases cause significant infirmity and mortality, and exact a high economic cost. Current medications either treat the symptoms and not the disease, or are nonspecifically targeted to inhibit the immune and inflammatory responses. New drugs that are highly specific designed on the basis of chemokine function should thus provide better treatments for these diseases.