Biomolecular Interactions of Factor VIII and von Willebrand Factor

血管性血友病因子（VWF）和因子VIII（FVIII）是启动和调节血管性血友病的关键中心蛋白。 止血。每一种都有自己的遗传性缺陷病，导致VWD或血友病A， 在血浆中以非共价复合物的形式一起循环。该项目探讨了建立 内皮细胞内VWF和FVIII蛋白之一或两者的调节分泌途径， 巨核细胞目标1将确定VWF中存储的结构和功能要求 的VWF和FVIII，并对比内皮细胞和血小板内的这些途径。维贝尔宫 身体对pro-VWF的合成有绝对的需求，而如果pro-VWF是 合成了特定目的2将确定在VWF存在下合成FVIII的体内潜力 作为治疗血友病A的新治疗方法。表达FVIII的转基因（F8-/-）动物 只在内皮细胞或巨核细胞中进行研究，以确定表达 FVIII和VWF。具体目标3将检查血小板特异性或内皮细胞特异性 FVIII表达作为绕过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局部释放活性FVIII“绕过”血浆抑制剂， 关于VWF特异性目的4将确定内皮细胞是否是FVIII表达的生理位点，或 至少是合成和储存通过施用DDAVP释放的FVIII的位点。以来 关于正常FVIII合成位点的争议仍在继续，这些研究将探讨DDAVP是否 FVIII的可释放池对FVIII的内皮合成具有绝对的要求，或者它是否可以在内皮细胞中产生。 缺乏特异性内皮细胞合成。将进行FVIII生产的组织特异性敲除 在肝细胞或内皮细胞中，以确定这些组织特异性敲除是否引起显著减少 血浆中的FVIII。因此，我们认为这些目标将明确地探讨VWF在体内和体外的功能， FVIII的体外细胞内生物学，并为治疗 在有和无FVIII抑制剂的患者中的血友病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.