Recognition of Fibrinogen by Leukocyte Integrins

白细胞整合素对纤维蛋白原的识别

• 批准号: 8197907
• 负责人: Tatiana P Ugarova
• 金额: $ 38.13万
• 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/8197907
• 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.

项目概要/摘要 白细胞整合素 aMb2 (CD11b/CD18, Mac-1) 在正常保护性炎症中发挥关键作用 反应和病理性炎症。这种受体具有惊人的粘附和信号传导能力 这使其成为东道主防守中的首要主力。它也是一个潜在的治疗靶点 炎症在许多疾病中起着重要作用，包括心血管疾病。这 aMb2 的多种功能和活性源于其结合多种结构的能力 不同的配体。然而，允许 aMb2 表现出广泛的配体识别的机制仍然未知。 不太了解。我们之前对 aMb2 配体纤维蛋白原原型的研究提供了初步见解 受体的 aMI 结构域识别其配体的机制。在过去的资助期内 我们已经解决了共识的 AMI 域识别基序，我们称之为 IRM。 IRM 的一个关键特性是 由普遍存在的碱性和疏水性氨基酸残基的特定组合组成的小核心 许多 aMb2 配体。 IRM 的特性与 aMb2 识别广泛信息的能力一致。 各种不相关的序列，因此形成 aMb2 配体结合混杂的分子基础。 具体目标1是进一步表征aMb2广泛识别特异性的机制。 组合肽文库和突变分析将用于阐明 IRM。质谱法将用于确定炎症相关蛋白的作用 对IRM功能的修改。我们的初步研究表明，中性粒细胞分泌产物 富含 IRM，这使得它们能够被预测为一类新的 aMb2 配体。我们发现了一个 其中，人中性粒细胞抗菌素肽 LL-37 可有效结合 aMb2 并产生有效的 aMb2- 依赖性迁移反应。基于这一发现，我们建议 LL-37 和其他中性粒细胞来源的 蛋白质/肽通过结合单核细胞/巨噬细胞上的 aMb2 发挥其有效的免疫调节作用。 具体目标 2 是通过表征由 aMb2 引起的依赖于 aMb2 的单核细胞反应来检验这一假设。 LL-37。 LL-37 对 aMb2 信号传导和迁移功能的影响将使用 aMb2- 来确定 表达和 aMb2 缺陷的细胞以及体内动物模型。过去资助期间的研究 鉴定出整合素 aDb2 是一种多配体受体，其特异性与 aMb2 相似，并揭示其 炎症巨噬细胞的上调抑制其迁移。具体目标 3 是表征 aMb2 和 aDb2（巨噬细胞上两种最丰富且粘附性最强的整合素）在巨噬细胞迁移中的作用 在炎症消退过程中从炎症部位排出细胞。巨噬细胞的流出 将在野生型和整合素缺陷小鼠中研究引流淋巴管。总体而言，这些研究将 导致对控制 aMb2 配体识别的原理有更多的了解，将提供新的 对 aMb2 和 aDb2 生物学的深入了解可能有助于设计新的治疗策略。