ENDOTHELIAL CELL DYSFUNCTION IN CHRONIC IMMUNE DISEASES

在慢性免疫和炎症性疾病中，一个特征是单核白细胞（淋巴细胞和单核细胞）在组织中持续募集和积累。许多证据表明，内皮细胞的功能障碍和/或激活是这一过程的关键因素。炎症细胞因子和细菌产物诱导局部内皮细胞活化并启动内皮依赖机制，介导白细胞牢固粘附和转运。尽管白细胞与内皮细胞的粘附相互作用受到了很多关注，但直到最近，白细胞通过内皮细胞侧连接的分子机制才成为研究的焦点。我们的实验室和其他研究表明，在迁移过程中，白细胞粘附改变内皮侧边界的粘附连接（例如，ve -钙粘蛋白复合物）（1-3）。连接粘附分子（Junction Adhesion Molecule， JAM）是最近发现的一种集中在小鼠内皮细胞和上皮细胞细胞边界的分子，在体内和体外参与内皮细胞间单核细胞的迁移(4)。本应用程序中提出的初步研究已经确定了假定的人类JAM分子。本应用的总体目标是在单核白细胞募集和内皮细胞侧连接功能的背景下，表征新发现的人类JAM粘附途径。特异性目的1将在体外血流模型中使用实时视频显微镜确定人类JAM在静息和细胞因子激活的内皮细胞中的表达，以及在白细胞-内皮细胞粘附级联中的确切作用。在Specific 2中提出的实验将确定JAM在内皮细胞间粘附（独立于白细胞粘附/转运）中的作用，以及与定位于细胞连接或细胞骨架的其他蛋白质的关联。Specific Aim 3将利用慢性炎症或免疫反应的体内模型来测试人类JAM在白细胞募集中的潜在作用。

In chronic immune and inflammatory diseases, a characteristic feature is the continued recruitment and accumulation in tissues of mononuclear leukocytes (lymphocytes and monocytes). Much evidence points to dysfunction and/or activation of endothelium as a critical factor underlying this process. Inflammatory cytokines and bacterial products induce localized endothelial cell activation and initiate endothelial-dependent mechanisms that mediate leukocyte firm adhesion and transmigration. Although much attention has been paid to leukocyte-endothelial adhesive interactions, only recently have the molecular mechanisms for leukocyte passage through the endothelial lateral junctions become a focus of study. Our laboratory and others have shown that leukocyte adhesion alters adherens junctions (e.g., VE-cadherin complex) at endothelial lateral borders, during the transmigration event (1-3). Junction Adhesion Molecule (JAM) is a recently identified molecule concentrated at cell-cell borders of murine endothelium and epithelium, and participates in monocyte transmigration across endothelial cells in vivo and in vitro (4). Preliminary studies presented in this application have identified the putative human JAM molecule. The overall goals of this application are to characterize the newly discovered human JAM adhesion pathway in the context of mononuclear leukocyte recruitment and function in endothelial cell lateral junctions. Specific Aim 1 will determine the expression of human JAM in resting and cytokine activated endothelium and the exact role in the leukocyte-endothelial adhesion cascade using live time videomicroscopy in an in vitro flow model. The experiments proposed in Specific 2 will determine the role of JAM in endothelial cell-to-cell adhesion (independent of leukocyte adhesion/transmigration) and association with other proteins localized to cell junctions or the cytoskeleton. Specific Aim 3 will utilize in vivo models of chronic inflammation or immune reactions to test the potential role of human JAM in leukocyte recruitment.