Recognition of Fibrinogen by Leukocyte Integrins

白细胞整合素对纤维蛋白原的识别

• 批准号: 8386971
• 负责人: Tatiana P Ugarova
• 金额: $ 36.3万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8386971
• 关键词: Adhesiveness; Adhesives; Affect; Amino Acids; Animal Model; Anti-Bacterial Agents; Atherosclerosis; Binding; Biological; Biology; Blood Circulation; CAP18 lipopolysaccharide-binding protein; Cardiovascular Diseases; Cell Surface Receptors; Cells; Characteristics; Consensus; Cytoplasmic Granules; Data; Disease; Emigrations; Endothelium; Exhibits; Family; Fibrinogen; Funding; Goals; Host Defense; Human; ITGAM gene; ITGB2 gene; Immune response; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Integrins; Knowledge; Lead; Leukocytes; Ligand Binding; Ligands; Lymphatic; Macrophage-1 Antigen; Mass Spectrum Analysis; Mediating; Methods; Modeling; Molecular; Mus; Pathogenesis; Peptide Library; Peptides; Play; Post-Translational Protein Processing; Process; Property; Protein Databases; Proteins; Reaction; Resolution; Rheumatoid Arthritis; Role; Signal Transduction; Site; Specificity; Surface; Testing; Translating; Up-Regulation; adhesion receptor; base; cathelicidin; combinatorial; design; in vivo; insight; macrophage; member; migration; monocyte; neutrophil; neutrophil basic protein; novel therapeutics; prototype; receptor; response; restenosis; therapeutic target

PROJECT SUMMARY/ABSTRACT Leukocyte integrin aMb2 (CD11b/CD18, Mac-1) plays a pivotal role in normal protective inflammatory response and pathological inflammation. This receptor has prodigious adhesive and signaling capabilities which allowed it to become the premier workhorse in host defense. It is also a potential therapeutic target in many diseases in which inflammation plays an essential role, including cardiovascular diseases. The diverse functions and activities ascribed to aMb2 arise from its ability to bind a multitude of structurally diverse ligands. However, the mechanisms which allow aMb2 to exhibit broad ligand recognition are still poorly understood. Our previous studies with a prototype aMb2 ligand fibrinogen provided initial insight into the mechanism by which the aMI-domain of the receptor recognizes its ligands. In the past funding period we have solved the consensus aMI-domain recognition motif, we termed IRM. A key feature of IRM is a small core consisting of specific combinations of basic and hydrophobic amino acid residues ubiquitous in many aMb2 ligands. The characteristics of IRM are consistent with the capacity of aMb2 to recognize a wide variety of unrelated sequences and, thus, form a molecular basis for aMb2 ligand binding promiscuity. Specific Aim1 is to further characterize the mechanism underlying broad recognition specificity of aMb2. Combinatorial peptide libraries and mutational analyses will be used to clarify the structural features of IRM. Mass spectrometry will be used to determine the effect of inflammation-associated protein modifications on the function of IRM. Our preliminary studies revealed that neutrophil secretion products are enriched in IRMs which allowed their prediction as a new class of aMb2 ligands. We have found that one of them, human neutrophil cathelicidin peptide LL-37, effectively binds aMb2 and unduces a potent aMb2- dependent migratory response. Based on this finding we propose that LL-37 and other neutrophil-derived proteins/peptides exert their potent immunomodulatory effects by binding aMb2 on monocyte/macrophages. Specific Aim 2 is to test this hypothesis by characterizing aMb2-dependent monocyte responses elicited by LL-37. The effect of LL-37 on signaling and migratory functions of aMb2 will be determined using aMb2- expressing and aMb2-deficient cells and in the in vivo animal model. Studies over the past funding period identified integrin aDb2 as a multiligand receptor with specificity similar to that of aMb2 and revealed that its upregulation on inflammatory macrophages inhibits their migration. Specific Aim 3 is to characterize the role of aMb2 and aDb2, two most abundant and adhesive integrins on macrophages, in emigration of these cells from the inflammatory site during the resolution of inflammation. The efflux of macrophages by draining lymphatics will be investigated in wild-type and integrin-deficient mice. Overall, these studies will lead to an increased understanding of the principles which govern ligand recognition by aMb2, will give new insights into the biology of aMb2 and aDb2 and may be useful in the design of novel therapeutic strategies.

项目总结/摘要 白细胞整合素aMb 2（CD 11b/CD 18，Mac-1）在正常的保护性炎症反应中起关键作用， 反应和病理性炎症。这种受体具有惊人的粘附和信号传递能力 这使得它成为东道主防守的首要主力。它也是一个潜在的治疗靶点， 炎症在许多疾病中起重要作用，包括心血管疾病。的 aMb 2的多种功能和活性源于其结合多种结构上 不同的配体。然而，允许aMb 2表现出广泛的配体识别的机制仍然是未知的。 不太了解。我们先前对原型aMb 2配体纤维蛋白原的研究提供了对以下方面的初步了解： 受体的aMI结构域识别其配体的机制。在过去的资助期间， 我们已经解决了共有的aMI-结构域识别基序，我们称之为aMI。的一个关键特性是 由碱性和疏水性氨基酸残基的特定组合组成的小核心，普遍存在于 许多aMb 2配体。aMb的特性与aMb 2识别广泛的 各种不相关的序列，并因此形成aMb 2配体结合混杂的分子基础。 特异性Aim 1是为了进一步表征aMb 2的广泛识别特异性的机制。 将使用组合肽文库和突变分析来阐明 - 是的质谱法将用于确定炎症相关蛋白的作用 在功能上进行了改进。我们的初步研究表明，中性粒细胞分泌产物 富含IRMs，这使得它们被预测为一类新的aMb 2配体。我们已经发现， 其中，人中性粒细胞cathelicidin肽LL-37有效地结合aMb 2，并诱导有效的aMb 2- 依赖性迁移反应基于这一发现，我们提出LL-37和其他嗜水气单胞菌衍生的 蛋白质/肽通过结合单核细胞/巨噬细胞上的aMb 2发挥其有效的免疫调节作用。 具体目的2是通过表征由以下引起的aMb 2依赖性单核细胞应答来检验该假设： LL-37 LL-37对aMb 2的信号传导和迁移功能的影响将使用aMb 2 - 37测定。 表达和aMb 2缺陷的细胞中以及在体内动物模型中。过去资助期间的研究 将整合素aDb 2鉴定为具有与aMb 2相似的特异性的多配体受体，并揭示其 炎性巨噬细胞上的上调抑制它们的迁移。具体目标3是表征 巨噬细胞上两种最丰富的粘附性整合素aMb 2和aDb 2在巨噬细胞迁移中的作用 在炎症消退期间从炎症部位清除细胞。巨噬细胞的流出， 将在野生型和整联蛋白缺陷小鼠中研究引流细胞。总的来说，这些研究将 导致对aMb 2控制配体识别的原理的理解增加，将给出新的 这将有助于深入了解aMb 2和aDb 2的生物学，并可能有助于设计新的治疗策略。