Critical molecular interactions of VWF and FVIII

血友病A已经得到了广泛的研究，基因治疗已经成为一种临床方法 动物模型和一些人体临床试验。由于治疗血友病A的标准方法已经 然而，要想取得成功，人们认为需要另类新颖的策略。一种这样的方法是 在过去的资金周期中在这笔赠款中开发，并侧重于用Megakaryo表达FVIII 细胞和内皮细胞。VWF和FVIII之间的自然相互作用可能有助于表达 并在临床上利用这些相互作用。这笔赠款有三个目的来探索相互作用 FVIII和VWF之间的关系，以及这如何导致优化血友病基因治疗的策略。 更令人兴奋的是，这种方法可能对已经发展成血友病的患者有利。 治疗-改变抑制性抗体。目标1将研究VWF复合体的局部和全身效应 在存在特异性FVIII抑制抗体的情况下与FVIII结合，并确定传递FVIII的安全性 在血小板中。目的2将研究FVIII在血小板中的传递，并确定其在大型动物中的疗效 血友病模型。目标3将研究一种基因治疗方法，在该方法中FVIII被合成并储存在 血管内皮细胞是否正常合成FVIII。这些模型将剖析 在存在抑制性抗体的情况下，VWF对FVIII治疗效果的贡献。自.以来 小鼠和狗的模型是没有人类疾病那么严重的临床模型，因为狗 正常情况下，血小板缺乏VWF。需要另一种具有血小板VWF的动物模型。绵羊模型的建立 血友病提供了这样一种模型，其特征是临床严重出血，其血小板中的VWF正常 和人类一样，最独特的是，胚胎绵羊模型已经被证明允许长期、终身的 人巨核细胞/血小板转导的人造血细胞的嵌合表达 速递和储存FVIII，可研究其安全性和临床疗效。这些研究将提供许多 这种新的血友病基因治疗方法的额外关键安全性和有效性，并提供了 在考虑进行人体试验之前，具有最高相关性的临床前模型。 相关性(请参阅说明)： 这笔赠款用于血友病的基因治疗，血友病是一种严重的临床出血。 无序。虽然大多数研究都是针对肝细胞，但我们独特的方法将针对表达的FVIII 到内皮细胞或巨核细胞--通常合成和储存VWF的细胞。这些方法 不仅可以治疗血友病患者，还可以治疗那些具有高滴度抑制作用的患者 抗体通常会缓解传统的替代疗法，甚至传统的基因 替代血浆中FVIII的治疗方法。

Hemophilia A has been widely studied, and gene therapy has been a clinical approach carried out in animal models and some human clinical trials. Since standard approaches for treating hemophilia A have yet to be successful, alternative novel strategies are thought to be needed. One such approach has been developed in this grant during the past funding cycle, and has focused on expressing FVIII in megakaryo¿¿ cytes and endothelial cells. The natural interactions between VWF and FVIII might facilitate the expression of FVIII and make use of these interactions clinically. This grant has three aims that explore the interactions between FVIII and VWF, and how this could lead to strategies to optimize gene therapy for hemophilia. Even more exciting, this approach might be advantageous for hemophilic patients who have developed treatment-altering inhibitory antibodies. Aim 1 will study the local and systemic effect of VWF complexes with FVIII in the presence of specific FVIII inhibitory antibodies, and determine the safety of delivering FVIII in platelets. Aim 2 will study the delivery of FVIII in platelets, and determine its efficacy in a large animal model of hemophilia. Aim 3 will study a gene therapy approach in which FVIII is synthesized in and stored by endothelial cells, and whether endothelial cells normally synthesize FVIII. These models will dissect the contribution of VWF to the therapeutic efficacy of FVIII in the presence of inhibitory antibodies. Since the murine and canine models are less severe clinical models than the human disorder, and because dog platelets normally lack VWF. another animal model with platelet VWF is needed. The ovine model of hemophilia provides just such a model characterized by clinical severe bleeding, normal VWF in its platelets like humans, and most uniquely, the fetal ovine model has been demonstrated to permit long-term, life-long chimeric expression of human hematopoietic cells where human megakaryocytes/platelets, transduced to express and store FVIII, can be studied for safety and clinical efficacy. These studies will provide much additional critical safety and efficacy on this novel approach to gene therapy for hemophilia and provide a pre-clinical model of highest relevance before considering human trials. RELEVANCE (See instructions): This grant addresses a novel strategy to carry out gene therapy of hemophilia, a severe clinical bleeding disorder. While most studies have targeted liver cells, our unique approach will targets the expressed FVIII to endothelial cells or megakaryocytes - cells that normally synthesize and store VWF. These approaches may not only treat patients with hemophilia, but also treat those patients that have high-titer inhibitory antibodies that would normally mitigate against traditional replacement therapy, or even traditional gene therapy approaches to replace FVIII in plasma.