Endothelial cell phosphatidylserine, topography, and procoagulant activity

描述（由申请人提供）： 血液凝固防止出血，也有助于血栓性疾病，包括心肌梗死，中风和静脉血栓栓塞。关于试管、动脉和静脉的血液凝固，人们已经了解了很多。然而，在单细胞水平上对血液凝固的调节在很大程度上尚未探索。在正常情况下，所有动脉和静脉的内皮细胞都具有抗凝特性。然而，在损伤或应激后，内皮细胞产生一些促凝血特性。我们的初步数据表明，强调或刺激的内皮细胞支持组装凝血酶原酶复合物在重点领域的细胞，同时保持抗凝蛋白的其他部分的细胞。促凝血活性的定位依赖于调节磷脂酰丝氨酸暴露和膜区域的凸曲率。因此，我们的数据表明，强调，活的内皮细胞可以支持促凝血酶活性在亚细胞水平，同时保持抗凝特性。 本提案的目的是确定三个主要的促凝血酶复合物的位置强调内皮细胞的细胞结构的细节和抗凝膜蛋白。我们将探讨局部酶复合物的功能后果，特别是关于产生少量的纤维蛋白结合到应激内皮细胞或细胞附近的基质。最后，我们将探讨最近确定的膜蛋白TMEM16 F的暴露磷脂酰丝氨酸发生在应激细胞的贡献。 我们的研究结果与对血液凝固机制及其在心脏病发作和中风中的参与的基本理解有关。它还与血液凝固机制在预防或限制细菌感染中的作用有关。最后，它也可能有助于解释血液凝固与炎症性疾病的关系。

DESCRIPTION (provided by applicant): Blood coagulation prevents hemorrhage and also contributes to thrombotic diseases including myocardial infarction, stroke, and venous thromboembolism. A great deal has been learned about blood coagulation on the scale of a test tube, an artery, and a vein. However, the regulation of blood coagulation at the single cell level has been largely unexplored. Under ordinary conditions endothelial cells that line all arteries and veins have anticoagulant properties. However, following injury or stress, endothelial cells develop some procoagulant properties. Our preliminary data demonstrates that stressed or stimulated endothelial cells support assembly of the prothrombinase complex in focal areas on the cell while maintaining anticoagulant proteins on other parts of the cell. Localization of procoagulant activity is dependent upon regulated phosphatidylserine exposure and convex curvature of membrane regions. Thus our data suggest that stressed, viable endothelial cells can support procoagulant enzyme activity at the subcellular level while maintaining anticoagulant properties. The objectives of this proposal are to identify the locations of the three major procoagulant enzyme complexes on stressed endothelial cells in relation to details of cell structure and in relation to anticoagulant membrane proteins. We will explore the functional consequences of the localized enzyme complexes, particularly with regard to generation of small quantities of fibrin that bind to stressed endothelial cells or to the matrix adjacent to the cells. Finally, we will explore the contribution of a recently identified membrane protein named TMEM16F to the exposure of phosphatidylserine that occurs on stressed cells. The results of our studies are relevant to fundamental understanding of the blood coagulation mechanism and its participation in heart attacks and strokes. It is also related to the role of the blood coagulation mechanism in preventing or limiting bacterial infections. Finally, it may also help to explain the relationship of blood coagulation to inflammatory diseases.