Inhibitors of the Intrinsic Pathway of Coagulation as New Anticoagulants

摘要 抗凝剂在临床上用于预防和/或治疗血栓性疾病。然而，目前所有的抗凝剂 与严重的内出血风险有关，从而限制了它们在各种疾病中的有效使用 患者群体。这一领域研究的长期目标是引入有效的抗凝血剂， 不会造成出血并发症，以便安全地用于更广泛的血栓患者。因此， 本项目旨在通过靶向体内的促凝血酶来开发安全有效的抗凝血剂。 凝血的内在途径，特别是凝血因子Xia(Fxia)和/或凝血因子XIIa(FXIIa)。临床上使用 抗凝剂直接或间接抑制凝血酶和/或凝血因子Xa的共同途径。 这就是它们临床有效的原因，但也是它们导致出血的原因。这个 中心假说是抑制人类FXIa或FXIIa的内在途径将导致有效的 保护动脉和静脉血栓，不会导致出血。FXIa或FXIIa的抑制剂 将主要防止血栓形成，并将使止血过程基本上完好无损。在预赛中 研究中，我发现了一种磺化的多肽模拟物，它以变构的方式抑制Fxia，具有中等效力和 对凝血酶和凝血因子Xa有显著的选择性。我还鉴定了一种苯甲酰胺，它能通过正构象作用抑制 FXIIa对一组相关的蛋白酶具有高效价和显著的选择性。不仅如此，而且每一位 这两种抑制剂还呈剂量依赖性地延长凝血时人体血浆的凝血时间 通过内在途径启动，这进一步支持了它们功能的特殊性。因此，这两个 FXIa和FXIIa的抑制剂作为有效和潜在安全的抗凝剂显示出非常有希望的特征，但 它们的药用和药理性能需要进一步改进。因此，我特别致力于； 1)化学合成先进的Fxia磺化变构抑制剂文库并对其进行评价 生化和生物潜力作为抗凝剂和2)化学合成一个先进的文库 以苯甲酰胺为基础的FXIIa邻位构型抑制剂及其生物化学和生物学潜力 抗凝剂。这项提议具有创新性，因为i)它提出了一种新的方法来克服 当前血栓治疗的局限性；ii)它采用了一种高度整合的多学科方法，涉及 合成药物化学、酶动力学、分子模拟和人体血浆试验 调查具体目标；以及iii)引入具有专有结构和机械的新技术 方面。该项目还具有重要意义，因为它将确定2-4种有效的和选择性的 血栓形成和出血动物模型中未来评估的内源性凝血途径。

SUMMARY Anticoagulants are clinically used to prevent and/or treat thrombotic diseases. Yet, all current anticoagulants are associated with a significant risk of internal bleeding which subsequently limits their effective use in various patient populations. The long-term goal of research in this area is to introduce effective anticoagulants that do not cause bleeding complications so as to be safely used for a wider range of thrombotic patients. Thus, this project aims at developing effective and safe anticoagulants by targeting procoagulant proteases in the intrinsic pathway of coagulation, particularly factor XIa (FXIa) and/or factor XIIa (FXIIa). Clinically used anticoagulants inhibit directly or indirectly thrombin and/or factor Xa of the common pathway of coagulation. This is the reason why they are clinically effective, but it is also the reason why they cause bleeding. The central hypothesis is that inhibiting human FXIa or FXIIa of the intrinsic pathway will result in effective protection against both arterial and venous thromboses without causing bleeding. Inhibitors of FXIa or FXIIa will primarily prevent thrombosis and will leave the hemostatic process essentially intact. In preliminary studies, I identified a sulfonated peptidomimetic that allosterically inhibits FXIa with moderate potency and significant selectivity over thrombin and factor Xa. I also identified a benzamide that orthosterically inhibits FXIIa with high potency and significant selectivity over a panel of related proteases. Not only that but each of these two inhibitors also dose-dependently prolongs the clotting time of human plasma when coagulation is initiated through the intrinsic pathway which further supports their specificity of function. Therefore, the two inhibitors of FXIa and FXIIa exhibit very promising profiles as effective and potentially safe anticoagulants, yet their pharmaceutical and pharmacological properties require further improvement. Thus, I specifically aim to; 1) chemically synthesize an advanced library of sulfonated allosteric inhibitors of FXIa and evaluate their biochemical and biological potential as anticoagulants and 2) chemically synthesize an advanced library of benzamide-based orthosteric inhibitors of FXIIa and evaluate their biochemical and biological potential as anticoagulants. The proposal is innovative because i) it puts forward a novel approach to overcome the limitations of current thrombosis treatment; ii) it exploits a highly integrated, multidisciplinary approach involving synthetic medicinal chemistry, enzyme kinetics, molecular modeling, and testing in human plasmas to investigate the specific aims; and iii) it introduces new technologies with proprietary structural and mechanistic aspects. The project is also significant because it will identify 2-4 potent and selective inhibitors of the intrinsic coagulation pathway for future evaluation in animal models of thrombosis and bleeding.