Antithrombotic Aptamers and Antidotes

 描述（由申请人提供）：本提案中测试了四个相互关联但独立的假设。A）适体可以作为分子探针来鉴定凝血因子蛋白酶上功能上重要的外部位点，B）在接触途径中抑制凝血因子的外部位点结合适体可以限制血栓形成而不增加出血，C）两种外部位点结合适体的组合以及适体和小分子活性位点抑制剂的组合代表有效的，但可以支持心肺转流手术的快速可逆抗凝策略和D）。靶向接触途径因子的外部位点结合因子IX/IXa适体将比靶向经历PCI的患者中的共同途径因子更有效地限制因子Xa和凝血酶产生和炎症。每一条调查路线都合理地建立在该奖项当前资助周期中取得的重要成果之上。我们的具体目标是：目标1：利用适体来鉴定凝血因子XIIa、XIa、IXa、Xa、VIIa和激肽释放酶上的外切位点。目的2：评估靶向接触途径因子上的外位点的适体作为有效而安全的抗血栓形成剂的能力。目标3：阐明因子Xa和凝血酶的A）基于适体的抑制剂和B）基于适体的外部位点和活性位点抑制剂的组合协同作用的机制，并确定此类组合是否可在心肺转流（CP B）中产生快速安全的抗凝作用，以及在CP B停药后，解毒剂是否可产生快速安全的抗凝中和作用。目标4：确定我们的因子IXa适体是否比伐卢定更有效地限制接受PCI的ACS患者中凝血酶和因子Xa的生成，以及这是否导致此类患者的炎症减少。

 DESCRIPTION (provided by applicant): Four interrelated but independent hypotheses are being tested in this proposal. A) Aptamers can serve as molecular probes to identify functionally important exosites on coagulation factor proteases, B) Exosite-binding aptamers that inhibit coagulation factors in the contact pathway can limit thrombosis without increasing bleeding, C) Combinations of two exosite-binding aptamers and combinations of an aptamer and small molecule active site inhibitor represent potent, yet rapidly reversible anticoagulation strategies that can support cardiopulmonary bypass surgery and D). The exosite binding Factor IX/IXa aptamer targeting a contact pathway factor will limit factor Xa and thrombin generation and inflammation more effectively than targeting common pathway factors in patients undergoing PCI. Each of these lines of investigation rationally build upon important results obtained in the current funding cycle of this award. Our specific aims are: Aim 1: To utilize aptamers to identify exosites on coagulation factors XIIa, XIa, IXa, Xa, VIIa and Kallikrein. Aim 2: To evaluate the ability of aptamers targeting exosites on contact pathway factors to act as potent yet safe antithrombotic agents. Aim 3: To elucidate the mechanism by which combinations of A) aptamer-based inhibitors and B) aptamer-based exosite and active site inhibitors of Factor Xa and thrombin synergize and determine if such combinations can produce rapid and safe anticoagulation for cardiopulmonary bypass (CPB) and if antidotes can produce rapid and safe neutralization of anticoagulation following discontinuation of CPB. Aim 4: To determine if our factor IXa aptamer limits thrombin and factor Xa generation more effectively than bivalirudin in ACS patients undergoing PCI and if this results in a reduction in inflammation in such patients.