T-type Calcium Channels and von Willebrand Factor Release

急性胸部综合征是由肺部炎症引起镰状红细胞粘附增加引起的 血细胞到肺微血管内皮。新出现的证据表明， 红细胞和内皮细胞是动态的。在非炎症状态下，抗粘连剂有助于灌注， 在炎症状态下，内皮细胞表面表达的蛋白质部分导致血管闭塞 通过上调粘附蛋白如P-选择素和释放血管性血友病因子（vWf）， 微血管内皮内皮细胞的分泌细胞器是内皮细胞特有的细胞器 叫做韦伯-帕拉德体在发炎的循环中，凝血酶和其他与Gq相关的神经体液 炎症介质增加内皮细胞胞质钙，这种胞质钙的升高是 足以引起韦伯-帕拉德小体快速移位至质膜，用于vWf分泌和P-选择素 上调刺激vWf分泌和P-选择素上调的特异性钙进入途径 仍然不完全了解，特别是在微血管内皮细胞获得的 血管闭塞的显著部位。初步研究表明肺微血管内皮细胞 表达促进促凝血内皮表型的T型电压激活钙通道 在炎症期间。在这个建议中，我们将测试钙通过T型细胞进入的总体假设， 钙通道是vWf释放和P-选择素上调的重要放大步骤， 促进镰状红细胞保留的肺微血管内皮。假设是 使用培养的肺微血管内皮细胞和分离的大鼠肺模型进行了探索， 可以在流动条件下评估T通道对红细胞滞留的作用。具体目标 检验以下假设：[1]肺微血管内皮细胞表达T型钙通道， 由Gq连接的神经体液炎症介质激活，和[2] T型钙通道的激活 促进肺微血管内皮细胞释放vWf和上调P-选择素 对血管闭塞很重要。希望这些研究的完成将提高我们对 调节红细胞-内皮细胞粘附的机制，以便可以开发有效的治疗方法， 治疗镰状细胞性贫血以及其他血管血栓形成疾病。

The acute chest syndrome is initiated by lung inflammation that induces increased adhesion of sickled red blood cells to pulmonary microvascular endothelium. Emerging evidence indicates the interaction between red blood cells and endothelium is dynamic. While in the non-inflamed state perfusion is facilitated by antiadhesive proteins expressed on the endothelial surface, in the inflamed state vaso-occlusion is partly caused by upregulation of adhesive proteins such as P-selectin and release of von Willebrand factor (vWf) from microvascular endothelium. The secretory organelle in endothelium is the endothelial cell specific organelle called Weibel-Palade body. In the inflamed circulation thrombin and other Gq-linked neurohumoral inflammatory mediators increase endothelial cell cytosolic calcium, and this rise in cytosolic calcium is sufficient to cause rapid translocation of Weibel-Palade bodies to the plasmalemma for vWf secretion and P-selectin up-regulation. Specific calcium entry pathways that stimulate vWf secretion and P-selectin upregulation remain incompletely understood, particularly in microvascular endothelial cells obtained from the prominent site of vaso-occlusion. Preliminary studies suggest that lung microvascular endothelial cells expess T-type, voltage-activated calcium channels which promote a pro-coagulant endothelial phenotype during inflammation. In this proposal, we will test the overall HYPOTHESIS that calcium entry through T-type calcium channels is an important amplification step in release of vWf and up-regulation of P-selectin from lung microvascular endothelium that promotes the retention of sickled red blood cells. The hypothesis will be explored using lung microvascular endothelial cells in culture and an isolated rat lung model, in which the role of the T channel to red blood cell retention can be assessed under flow conditions. The SPECIFIC AIMS test the hypotheses that: [1] Lung microvascular endothelial cells express a T-type calcium channel that is activated by Gq-linked neurohumoral inflammatory mediators, and [2] Activation of T-type calcium channels promotes the release of vWf and up-regulation of P-selectin from lung microvascular endothelial cells important for vaso-occlusion. It is hoped completion of these studies will improve our understanding of mechanisms that regulate erythrocyte-endothelial adherence so that effective therapies can be developed for treatment of sickle cell anemia, as well as other vascular thrombosis disorders.