Novel Therapeutics for Acquired Thrombotic Thrombocytopenic Purpura

描述（由申请人提供）：血栓性血小板减少性紫癜（TTP）是一种致命综合征。获得性TTP主要由抑制ADAMTS13酶的自身抗体引起。血浆置换是迄今为止唯一有效的治疗方法。在本提案的目的1中，我们将重新设计和表征一系列新的重组ADAMTS13变体，这些变体表现出更高的特异性活性，但对获得性TTP患者的自身抗体抑制具有抗性。这一目标的完成将为ADAMTS13的结构-功能关系提供新的见解，并改变我们今天对待TTP的方式。在Aim 2中，我们建议使用我们新颖和突破性的氘交换结合质谱分析方法在氨基酸分辨率上确定抗原结合表位。此外，我们将在实验室建立的小鼠动脉血栓形成和TTP模型中确定一组抑制性scFV的致病性。从这项研究中获得的信息可能有助于我们理解获得性TTP的分子机制，并合理设计具有所需特性（如对自身抗体抑制的抗性）的新型重组ADAMTS13变体，以用于未来的治疗。最后，在Aim 3中，我们将验证一个假设，即血小板中野生型ADAMTS13和功能获得/抗体抗性ADAMTS13变体的异位表达将直接靶向治疗酶到损伤部位，而不会被循环中的抗ADAMTS13抗体抑制。总的来说，本研究的完成将为ADAMTS13的结构-功能关系提供新的见解，有助于我们理解获得性TTP的机制，并为这种致命的TTP综合征的潜在治疗提供新的工具。

DESCRIPTION (provided by applicant): Thrombotic thrombocytopenic purpura (TTP) is a fatal syndrome. Acquired TTP is mainly caused by autoantibodies that inhibit ADAMTS13 enzyme. Plasma exchange is the only effective therapy available to date. In Aim1 of this proposal, we will reengineer and characterize a series of novel recombinant ADAMTS13 variants that exhibit increased specific activity, but are resistant to inhibition by autoantibodies from patients with acquired TTP. The completion of this aim will provide novel insights into the structure-function relationship of ADAMTS13 and change how we treat TTP today. In Aim 2, we propose to determine the antigenic binding epitopes at the amino acid resolution using our novel and groundbreaking deuterium exchange coupled with mass spectrometric analysis approaches. In addition, we will determine the pathogenicity of a panel of inhibitory scFV(s) in murine models of arterial thrombosis and TTP established in the laboratory. The information gained from this study may help our understanding of the molecular mechanisms of acquired TTP and the rational designing of novel recombinant ADAMTS13 variants with desired properties (such as resistance to autoantibody inhibition) for future therapy. Finally, in Aim 3, we will test the hypothesis that ectopic expression of wild-type ADAMTS13 and gain-of-function/antibody-resistant ADAMTS13 variants in platelets would target the therapeutic enzyme directly to sites of injury without being inhibited by circulating anti-ADAMTS13 antibodies. Overall, the information obtained from the completion of the proposed study will provide novel insight into the structure-function relationship of ADAMTS13, help our understandings of the mechanisms of acquired TTP, and provide novel tools for potential therapy of such a fatal TTP syndrome.