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The Role of CD47 in Mononuclear Leukocyte Recruitment

CD47 在单核白细胞募集中的作用

基本信息

批准号：
7753041
负责人：
FRANCIS W. LUSCINSKAS
金额：
$ 61.36万
依托单位：
BRIGHAM AND WOMEN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7753041
关键词：
Actins Address Adhesions Adhesives Affinity Agonist Air Anti-Inflammatory Agents Anti-inflammatory Apical Atherosclerosis Autoimmune Diseases Avidity Binding Biochemical Biological Biological Assay CD47 Antigen CD47 gene Cell Adhesion Cell membrane Cells Chronic Clinical Complex Cytoskeleton Data Diffuse Disease Encephalomyelitis Endothelial Cells Endothelium Event Exhibits Experimental Autoimmune Encephalomyelitis Experimental Models Functional disorder Genetic Imagery Immune Immune System Diseases In Vitro Inflammation Inflammatory Integrin alpha4beta1 Integrins Intercellular Junctions Intercellular adhesion molecule 1 Knockout Mice Lateral Leukocytes Life Ligand Binding Ligands Mediating Microcirculation Microscopy Modeling Molecular Mononuclear Leukocytes Mus Names Null Lymphocytes PTPNS1 gene Pathogenesis Pathway interactions Pertussis Toxin Physiological Play Principal Investigator Process Proteins Regulation Role SHPS-1 protein Signal Transduction Skin Small Interfering RNA Symptoms T-Lymphocyte T-Lymphocyte Subsets Thrombospondin 1 Thrombospondins Tyrosine Phosphorylation Vascular Cell Adhesion Molecule-1 Work base cadherin 5 cell motility cell type cellular imaging extracellular in vivo in vivo Model insight intravital microscopy migration monocyte particle programs small hairpin RNA thrombospondin 2

项目摘要

Recruitment and retention of chronic inflammatory leukocytes (e.g.,T cell subsets and monocytes) is a pivotal step in initiation and progression of chronic inflammatory diseases including atherosclerosis and autoimmune diseases. In this revised application, we propose a detailed plan to study the role of CD47 and its ligands, SIRPa and SIRPy, and thrombospondin-1 and -2 (TSPs), at a molecular level in mononuclear leukocyte recruitment using in vitro and in vivo models. In SPECIFIC AIM 1, the role ofthe CD47 - SIRP and CD47 - TSPs adhesive interactions in recruitment of mononuclear leukocytes will be studied by multiple strategies using in vivo and in vitro approaches. The contributions of this pathway to mononuclear leukocyte transendothelial cell migration will be dissected in a live-cell imaging model of transmigration under defined shear flow conditions in vitro. We will make use of function blocking mAbs, shRNA knockdown, and leukocytes and cultured endothelial cells from CD47''' and TSP-1/2''" mice. These analyses will be corroborated by direct visualization of leukocyte interactions with the microvessel wall using an intravital microscopy approach. In addition, the ability of CD47 to cluster around actively transmigrating leukocytes and to trigger intracellular signaling events required for leukocyte transendothelial cell migration will also be addressed. In Specific Aim 2, studies will investigate CD47 mediated regulation of leukocyte VLA-4 and LFA-1 integrin function. CD47 associates with avp3 and VLA-4 integrins and has been shown to regulate integrin function by "in cis" interactions that signal through a heterotrimeric Gi-coupled complex. Based on biochemical evidence other studies suggest CD47 regulation of integrin ligand binding does not work via its signaling and instead requires direct physical interaction between its extracellular Ig domain and Ov integrins. We hypothesize that through direct association with VLA-4 integrins, CD47 regulates integrin diffusivity in the plasma membrane, and that this has functional consequences for integrin activation. In support of our hypothesis, our preliminary data working in T cells indicate VLA-4 integrin diffused three-fold greater in CD47 null cells and that CD47 null cells exhibit a marked reduction in binding to VCAM-1 and ICAM-1 under shear flow conditions. We propose to investigate the mechanism of CD47 regulation of VLA-4 and LFA-1 integrin dependent functions in mononuclear leukocytes by cell biological, biophysical and biochemical assays. In SPECIFIC AIM 3, we will determine the role of CD47 in mononuclear leukocyte recruitment in an experimental model of immunemediated disease using CD47"'" mice. Only a limited number of studies have evaluated the role of CD47 in chronic immune or inflammatory processes in vivo. Our experimental approach will be to determine the role of CD47 in the recruitment of pathogenic T cells in a murine model of experimental autoimmune encephalomyelitis (EAE). The proposed studies in these three Aims will provide new insights for CD47 dependent regulation of chronic inflammatory leukocyte function and recruitment and may provide new avenues for anti-inflammatory therapies.

慢性炎性白细胞（如T细胞亚群和单核细胞）的募集和滞留是一种疾病