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.

项目摘要/摘要 白细胞整合素AMB2（CD11b/CD18，MAC-1）在正常保护性炎症中起关键作用 反应和病理炎症。该受体具有惊人的粘合剂和信号传导功能 这使其成为主持人防御的主要主力军。它也是潜在的治疗靶点 许多炎症起着重要作用的疾病，包括心血管疾病。这 归因于AMB2的各种功能和活动是由于其结构上绑定多种结构的能力而产生的 多样的配体。但是，允许AMB2表现出广泛识别的机制仍然是 理解不佳。我们先前对原型AMB2配体纤维蛋白原的研究提供了对 受体AMI域识别其配体的机制。在过去的资金期间 我们已经解决了共识AMI识别识别图案，我们称为IRM。 IRM的关键特征是 小核由碱性和疏水性氨基酸残基无处不在的特定组合组成 许多AMB2配体。 IRM的特征与AMB2识别广泛的能力一致 多种无关序列，因此构成了AMB2配体结合杂交的分子基础。 具体目标是进一步表征AMB2的广泛识别特异性的基础机制。 组合肽库和突变分析将用于阐明的结构特征 IRM。质谱法将用于确定炎症相关蛋白的影响 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 丰富了IRM，这使他们可以预测为新的AMB2配体。我们发现一个 其中，人类嗜中性粒细胞cathelicidin肽LL-37有效地结合了AMB2并取消了有效的AMB2- 依赖的迁移反应。基于这一发现，我们建议LL-37和其他中性粒细胞衍生 蛋白质/肽通过结合AMB2对单核细胞/巨噬细胞的结合发挥其有效的免疫调节作用。 特定目的2是通过表征由AMB2依赖性单核细胞反应来检验这一假设的。 LL-37。 LL-37对AMB2的信号传导和迁移功能的影响将使用AMB2-确定 表达和AMB2缺陷型细胞以及体内动物模型。在过去的资金期间学习 将整合素ADB2识别为具有类似AMB2的特异性的多物体受体，并揭示了其 炎症性巨噬细胞的上调抑制了它们的迁移。特定目的3是表征 AMB2和ADB2的作用，两种最丰富和粘合剂整合蛋白在巨噬细胞中的作用，在这些巨噬细胞中 炎症分辨率期间炎症部位的细胞。巨噬细胞的外流 排水淋巴管将在野生型和整联蛋白缺陷型小鼠中进行研究。总体而言，这些研究将 导致人们对管理AMB2配体认可的原理的理解将给予新的 对AMB2和ADB2生物学的见解，并且可能在新型治疗策略的设计中有用。