Targeting PAR4 in Thrombotic Disorders:Pharmacogenomic Approach

项目摘要 虽然在过去的40年里，心脏病和中风的死亡率急剧下降，但这些血栓性疾病的发生率仍然很高。 疾病仍然是我们最大的杀手。这项资助的总体目标是开发一种新的抗血小板药物 用于管理血栓形成的风险和治疗的化合物。血小板在血栓形成中起关键作用， 死亡和发病的主要原因。急性冠状动脉综合征与脑血管病的内科治疗 抗血小板疗法是治疗创伤的中心。凝血酶是蛋白酶激活受体的必需激活剂 (PAR)用于产生止血栓。人血小板同时具有PAR1，即高亲和力的 血管壁止血基础的凝血酶受体和低亲和力凝血酶受体PAR 4 其在凝块中被缓慢激活，因为其需要大量的凝血酶积累。我们的指导假设 PAR4是血栓形成和脑血管损伤中抗血小板治疗的有吸引力的靶点，因为 它在3D凝块的位置的局部激活，因为更多的凝血酶积聚。我们假设PAR4 拮抗作用可能使血管中的凝块积聚最小化，但不会有效地影响止血， 减少出血副作用，成为更好的抗血小板治疗靶点。黑人有一个显著的 心脏病和中风的发病率更高，生存率更低。最近，一个过度活跃的PAR4等位基因被发现， 在63%的黑人中发现并发现发生，但只有16%的白人。我们使用了HTS和药物 化学方法以获得阻断两个等位基因的PAR 4的nM和pM亲和拮抗剂。我们建议优化 我们的先导分子对这两种PAR4等位基因的生物利用度、效力和选择性，并在 血栓形成的狒狒分流模型。我们将1）使用文库优化最佳系列的PAR 4拮抗剂 方法，2）确定化合物的选择性和效力，并将具有不同 3）确定这些药物的药代动力学、代谢和处置 PAR 4拮抗剂在狒狒和人中的体外试验和在狒狒中的体内试验，和4）在哺乳动物中测试优化的化合物。 流动下的人血小板和狒狒血栓形成分流模型。这些目标的实现将为 在血栓形成的灵长类动物模型中的证据表明PAR 4拮抗作用是安全有效的。长期目标是 证明PAR 4作为预防和治疗性抑制病理性 血栓形成对过度活跃的PAR 4等位基因有活性的拮抗剂可能具有以下潜力： 发展成为一种理想的抗血小板药物，可以减少血栓性疾病结局的种族差异， 事件

PROJECT SUMMARY Though deaths from heart disease and stroke have fallen dramatically in the last 40 years, these thrombotic diseases are still our largest killer. The overall goal of this grant is to develop a new class of anti-platelet compounds for managing the risk and treatment of thrombosis. Platelets play a critical role in thrombosis, the major cause of mortality and morbidity. Medical management of acute coronary syndrome and cerebrovascular injury is centered on anti-platelet therapies. Thrombin is an essential activator of protease activated receptors (PAR) in platelets for generation of a hemostatic plug. Human platelets have both PAR1, the high-affinity thrombin receptor that underlies hemostasis at the vessel wall, and PAR4, the low-affinity thrombin receptor which is activated slowly in the clot because it requires substantial thrombin build up. Our guiding hypothesis is that PAR4 is an attractive target for anti-platelet therapy in thrombosis and cerebrovascular injury, because of its local activation at the site of the 3D clot as more thrombin builds up. We hypothesize that PAR4 antagonism might minimize clot build-up in the vessel, but not affect hemostasis as potently and thus may decrease bleeding side effects and be a better therapeutic anti-platelet target. Blacks have a significantly higher incidence of heart disease and stroke and worse survival. Recently, a hyperactive PAR4 allele was discovered and found to occur in 63% of blacks but only 16% of whites. We have used HTS and medicinal chemistry to obtain nM and pM affinity antagonists of PAR4 which block both alleles. We propose to optimize bioavailability, potency, and selectivity of our lead molecules for both of these PAR4 alleles and test them in a baboon shunt model of thrombosis. We will 1) optimize the best series of PAR4 antagonists using a library approach, 2) determine selectivity and potency of compounds, and carry forward compounds that have diverse modes of action to maximize safety 3) determine the pharmacokinetics, metabolism and disposition of these PAR4 antagonists in vitro in baboon and human and in vivo in baboon, and 4) test the optimized compound in human platelets under flow and in a baboon shunt model of thrombosis. Completion of these aims will provide evidence in primate models of thrombosis that PAR4 antagonism is safe and efficacious. The long-term goal is to demonstrate PAR4 as an alternative target for preventive and therapeutic suppression of pathologic thrombus formation. An antagonist that is active against the hyperactive PAR4 allele may have the potential to develop into an ideal anti-platelet agent that can decrease the racial disparity of outcomes of thrombotic events.