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

趋化因子单体-二聚体平衡在先天免疫和炎症中的作用

• 批准号: 7083124
• 负责人: Krishna Rajarathnam
• 金额: $ 32.28万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7083124
• 关键词: chemokine; dimer; immunity; inflammation; monomer; neutrophil; respiratory reflex; role

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.

描述（由申请人提供）：趋化因子CXCL 8（也称为白细胞介素-8）通过从血流中募集中性粒细胞到被细菌感染等损伤损伤的组织中，在先天免疫和炎症中起关键作用。我们的长期目标是了解CXCL 8功能的分子机制，从而为新的抗炎治疗奠定基础。CXCL 8通过与中性粒细胞上的G蛋白偶联受体（GPCR）以及细胞外基质和内皮上的糖胺聚糖（GAG）结合来发挥其功能。趋化因子的一个基本性质是能够可逆地作为单体和二聚体存在。因此，了解CXCL 8单体和二聚体与GPCR和GAG的结合对于了解体内中性粒细胞募集至关重要。我们的假设是，四种CXCL 8形式（溶液中的单体和二聚体以及与GAG结合的单体和二聚体）之间的动态平衡调节体内中性粒细胞的募集。在这个项目中，我们将测试我们的假设，通过表征被困单体和二聚体和天然CXCL 8的突变体，显示降低结合GPCR或GAG，和天然CXCL 8的突变体，显示降低二聚化效力。我们将确定单体-二聚体平衡以及单体和二聚体对GAG和GPCR的结合相互作用如何在动物模型中调节体内CXCL 8功能（目的1）。我们将确定单体和二聚体是否引发类似的信号传导事件（但具有不同的效力），或引发独特的信号传导事件（目的2）。最后，通过确定单体和二聚体如何结合GAG，我们将更好地确定单体和二聚体在溶液中的分布以及与GAG的结合（目的3）。我们研究设计的创新包括使用生物物理，体外细胞和体内动物研究的组合;新型试剂（捕获的单体和二聚体）;和一种新的微流体装置技术来测量趋化性。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学中起着核心作用。这些疾病造成严重的虚弱和死亡，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，根据趋化因子功能设计的高度特异性的新药应该为这些疾病提供更好的治疗方法。