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CXCL8（也称为白介素-8）通过募集中性粒细胞从血液中的嗜中性粒细胞募集到受细菌感染等侮辱而受损的组织中，在先天免疫和炎症中起关键作用。我们的长期目标是了解CXCL8功能的分子机制，因此为新的抗炎治疗奠定了基础。 CXCL8通过在中性粒细胞上与G蛋白偶联受体（GPCR）以及在细胞外基质和内皮上的糖胺聚糖（GAGS）结合来发挥其功能。趋化因子的基本特性是可以作为单体和晚餐可逆地存在的能力。因此，对CXCL8单体和二聚体与GPCR和GAG的结合的知识对于理解体内嗜中性粒细胞募集至关重要。我们的假设是，在溶液，单体和晚餐中，四种CXCL8形式，单体和晚餐之间的动态平衡与插科打结合，调节体内嗜中性粒细胞的募集。在这个项目中，我们将通过表征被困的单体和二聚体的突变体以及天然CXCL8的突变体，这些突变体显示出与GPCR或GAGS的结合减少，而天然CXCL8的突变体显示出降低的二聚化效力。我们将确定单体二聚体平衡以及GAG和GPCR的单体和二聚体的结合相互作用如何在动物模型中调节体内CXCL8功能（AIM 1）。我们将确定单体和晚餐是否引起类似的信号事件（但具有不同的效力），还是引起独特的信号事件（AIM 2）。最后，通过确定单体和二聚体如何结合插科打术，我们将更好地定义溶液中单体和二聚体的分布并与插科打结合（AIM 3）。我们的研究设计中的创新包括结合生物物理，基于体外细胞和基于体内动物的研究；新型试剂（被困的单体和二聚体）；以及一种测量趋化性的新型微流体设备技术。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患病和死亡率，并确切地造成高昂的经济成本。当前的药物要么治疗症状，而不是疾病，要么无针对性地抑制免疫和炎症反应。因此，基于趋化因子功能高度特异性设计的新药应为这些疾病提供更好的治疗方法。