In Vivo Sickle Cell Vasoocclusion: Adhesion Mechanisms

描述（由申请人提供）： 本提案的总体目标是了解粘合剂 镰状细胞病中介导血管闭塞的机制。虽然 一些研究已经证明了许多粘附分子的作用 在体外镰状细胞粘附中，很少有体内数据。 最近开发出一种小鼠品系， 人类球蛋白为我们提供了研究 使用活体显微镜观察体内机制。我们的初步研究 表明马槟榔诱导的炎症产生严重的 提睾肌毛细血管后小静脉血管闭塞 镰状细胞小鼠我们的研究结果表明，粘附的白细胞发挥作用， 因为它们可以结合循环中的镰状细胞， 红细胞（SS RBC）并引发小静脉闭塞。内皮 选择素缺陷小鼠，其在白细胞募集中显示缺陷 在小静脉中，SS RBC与白细胞的相互作用很少，也没有血管闭塞。 在本提案中，我们希望进一步研究以下假设： 镰状细胞病中的血管闭塞是由粘附剂 SS RBC和粘附白细胞之间的相互作用。在具体目标I中， 我们将确定白细胞的类型（单核细胞vs 多态性）与SS RBC在体内相互作用，我们将 进一步评估白细胞和内皮细胞粘附的作用 使用粘附分子敲除小鼠的血管闭塞中的粘附分子， 抑制性抗体;我们还将开发一个模型来研究 骨髓微血管的血管闭塞，一个重要的目标 在镰状细胞病中。在具体目标II中，我们将开发粘附力 分析介导SS RBC-白细胞的分子机制 相互作用，同时，我们将进行活体实验， 证实了假定的粘附途径。在具体目标三中，我们建议 评价三种粘附分子的体内功能， 显示参与镰状细胞粘附（vonWillebrand因子， β 3整联蛋白和血小板反应蛋白），使用粘附分子敲除 小鼠和镰状细胞动物。拟议中的研究应提供新的 阐明了镰状细胞血管闭塞的体内机制， 导致治疗镰状细胞危象和其他并发症的新方法 这种疾病。

DESCRIPTION (provided by applicant): The overall objective of this proposal is to understand the adhesive mechanisms mediating vaso-occlusion in sickle cell disease. Although several studies have documented roles for a number of adhesion molecules in sickle cell adhesion in vitro, there is very little in vivo data. The recent development of a mouse strain that exclusively expresses human globins provides us with the opportunity to study the adhesive mechanisms in vivo using intravital microscopy. Our preliminary studies indicate that cytokine-induced inflammation produces severe vasoocclusion in post-capillary venules in the cremaster muscle of sickle cell mice. Our results indicate that adherent leukocytes play a key role in this process since they can bind circulating sickle cell erythrocytes (SS RBCs) and initiate venular occlusion. Endothelial selectin-deficient mice, which display defects in leukocyte recruitment in venules, show few SS RBC-leukocyte interactions and no vasooclusion. In this proposal, we wish to further investigate the hypothesis that vasooclusion in sickle cell disease is initiated by the adhesive interaction between SS RBCs and adherent leukocytes. In specific aim I, we will identify the type of leukocyte (mononuclear vs polymorphonuclear) that interacts with SS RBCs in vivo, and we will further evaluate the roles of leukocyte and endothelial adhesion molecules in vasoocclusion using adhesion molecule knockout mice and inhibitory antibodies; we will also develop a model to investigate vasoocclusion in the bone marrow microvasculature, an important target in sickle cell disease. In specific aim II, we will develop adhesion assays to dissect the molecular mechanisms mediating SS RBC-leukocyte interactions and, in parallel, we will conduct intravital experiments to confirm putative adhesion pathways. In specific aim III, we propose to evaluate the in vivo functions of three adhesion molecules previously shown to participate in sickle cell adhesion (von Willebrand factor, beta3 integrins and thrombospondin), using adhesion molecule knockout mice and sickle cell animals. The proposed studies should shed new light on the in vivo mechanisms of sickle cell vasoocclusion and may lead to novel ways to treat sickle cell crises and other complications of this disease.