Biomolecular Interactions of Factor VIII and von Willebrand Factor

血管性假血友病因子(VWF)和第八因子(FVIII)是启动和调节血管紧张素转换酶的关键中心蛋白。 止血。每个人都有自己的遗传性缺乏症，这种疾病会导致VWD或血友病A，而且他们 在血浆中以非共价络合物的形式一起循环。本项目探讨了建立的要求 血管内皮细胞内VWF和FVIII蛋白中的一个或两个的调节分泌途径 巨核细胞。目标1将确定VWF内对存储的结构和功能要求 并对比了血管内皮细胞和血小板内的这些途径。韦贝尔-帕拉德 Body对合成Pro-VWF有绝对要求，如果Pro-VWF是 合成的。特异性目标2将确定在VWF存在的情况下FVIII的体内合成潜力 作为一种治疗血友病的新方法A.表达FVIII的转基因动物(F8-/-) 只有在内皮细胞或巨核细胞中才会进行研究，以确定表达的治疗优势 与VWF合作的FVIII。特异性目标3将检测血小板特异性或内皮细胞特异性的可能性 FVIII的表达可作为一种绕过FVIII抗体抑制活性的手段。转基因动物 在内皮细胞或血小板中表达FVIII将在抑制抗体的背景下进行研究 确定这些表达位点是否可以通过在上下文中局部释放活性FVIII来“绕过”血浆抑制物 VWF的。具体目标4将确定内皮细胞是否是FVIII或FVIII表达的生理部位 至少是DDAVP管理部门发布的合成和存储FVIII的站点。自.以来 关于FVIII的正常合成部位的争论仍在继续，这些研究将探索DDAVP是否 可释放的FVIII池对内皮合成FVIII有绝对要求，或者它是否可以在 缺乏特异的内皮细胞合成。将进行FVIII生产的组织特异性敲除 以确定这些组织特异性基因敲除是否导致显著减少 在血浆FVIII中。因此，我们认为，TIISE AIMS将最终探索VWF在体内和 FVIII的体外细胞内生物学特性，为新的治疗方法提供了潜在的可能性 在使用和不使用FVIII抑制剂的患者中都存在血友病A。

Von Willebrand Factor (VWF) and Factor VIII (FVIII) are key central proteins in the initiation and regulation of hemostasis. Each has its own hereditary deficiency disease, which cause either VWD or hemophilia A, and they circulate together as a non-covalent complex in plasma. This project explores the requirements for the establishment of a regulated secretory pathway for one or both VWF and FVIII proteins within endothelial cells and megakaryocytes. Aim 1 will determine the structural and functional requirements within VWF for the storage of both VWF and FVIII and contrasts these pathways within endothelial cells and platelets. The Weibel-Palade body has an absolute requirement for synthesis of pro-VWF while the alpha granule is permissive if pro-VWF is synthesized. Specific Aim 2 will determine the in vivo potential for synthesis of FVIII in the presence of VWF as a novel therapeutic approach in the treatment of hemophilia A. Transgenic (F8-/-) animals expressing FVIII only in either endothelium or megakaryocytes will be studied to determine the therapeutic advantage of expressing FVIII with VWF. Specific Aim 3 will examine the potential for platelet-specific or endothelial cell-specific FVIII expression as a means to bypass the inhibitory activity of FVIII antibodies. Transgenic animals expressing FVIII in endothelial cells or platelets will be studied within the context of inhibitory antibodies to determine if these sites of expression can "bypass" plasma inhibitors by locally releasing active FVIII in the context of VWF. Specific Aim 4 will determine if the endothelial cell is the physiologic site for expression of FVIII or at least the site synthesizing and storing the FVIII released by the administration of DDAVP. Since the controversy continues as to the site of normal FVIII synthesis, these studies will explore whether the DDAVP releasable pool of FVIII has an absolute requirement for endothelial synthesis of FVIII or whether it can be created in the absence of specific endothelial cell synthesis. Tissue specific knockouts of FVIII production will be carried out in the hepatocyte or in the endothelial cell to determine if these tissue-specific knockouts caused a marked reduction in plasma FVIII. Therefore, we feel that tiiese aims will definitively explore the function of VWF on the in vivo and in vitro intracellular biology of FVIII and provide potential for new therapeutic approaches to the treatment of hemophilia A both in patients with and those without FVIII inhibitors.