凝血酶受体拮抗剂的研究进展

血栓栓塞性疾病严重威胁人类健康,应用抗血小板药物是当前主要的治疗手段之一。研究证明,凝血酶受体(又称蛋白酶激活受体-1,PAR-1)被凝血酶激活后,可诱导血小板活化。此外,PAR-1主要参与病理性血栓的形成,对人体正常的止血过程影响很小。因此,PAR-1已成为抗血小板药物研发的新兴靶点。目前,已有多个PAR-1拮抗剂如vorapaxar、F16618、F16357、ML161、RWJ-58259、PZ-128已上市或进入临床研究。综述了PAR-1的结构和作用机制以及小分子拮抗剂和多肽类拮抗剂的研究进展。     

FDA批准抗血小板药Zontivity用于心梗和卒中高危患者

2014年5月美国FDA批准Zontivity（vorapaxar）用于心肌梗死、卒中或外周动脉疾病患者,以减少心梗、卒中、心血管相关的死亡和冠脉血管重建的风险。PAR-1是一种可被凝血酶激活的受体,而凝血酶是一种有效的血小板激活剂。Zontivity是一种首创的蛋白酶激活受体1拮抗剂,可以抑制凝血酶诱导的血小板激活,抑制血小板聚集。     

蛋白酶激活受体-4拮抗剂的研究进展

蛋白酶激活受体-4(PAR-4)是一个由300个氨基酸经过7次跨膜形成的G蛋白偶联受体,它可通过与凝血酶的结合诱导血小板聚集,参与凝血过程。因此,PAR-4受体可以作为抗血小板药物的新靶点。近年来研究者发现了3种不同结构类型的小分子PAR-4受体拮抗剂,分别含有吲唑、吲哚和咪唑并噻二唑结构。对这几种拮抗剂的结构、药理活性等方面的研究进展进行综述。     

Vorapaxar sulfate

<正>2014年5月8日由默沙东公司开发的vorapaxar sulfate被美国食品药品监督管理局(FDA)批准上市,其商品名为Zontivity。该药是一种蛋白酶激活受体-1(PAR-1)拮抗剂,适用于有心肌梗死或有外周动脉疾病史患者中血栓性心血管事件的减低[1]。     

应用于抗血栓治疗的新凝血酶受体抑制剂SCH-530348

喜巴辛衍生物SCH-530348是蛋白酶激活受体1(PAR-1)的抑制剂,PAR-1是人血小板凝血酶最主要的一种受体。SCH-530348是第一种能抑制凝血酶诱导的血小板聚集而不影响凝血酶对胶原酶原活化能力的化合物。文中综述了SCH-530348的临床前和Ⅰ～Ⅲ期临床试验结果。这些研究表明SCH-530348具有降低缺血性事件发生风险的几率,同时不会明显增加机体出血的风险,临床上可应用于急性冠脉综合征的治疗和缺血性心血管事件的预防。     

N-取代-3-吲哚乙酰胺类α1-肾上腺素受体拮抗剂的合成及生物活性

目的设计合成新型吲哚乙酰胺类α1-肾上腺素受体拮抗剂,评价其α1-肾上腺素受体拮抗活性.方法 结合α1-肾上腺素受体拮抗剂的构效关系和计算机辅助药物设计方法所构建的药效团模型,设计合成了19个N-取代-3-吲哚乙酰胺类化合物,并测定拮抗参数pA2值.结果 18个化合物未见文献报道,其结构均经1H-NMR、IR及ESI-MS(HRMS)确证.结论 初步生物活性测试表明:所合成的目标化合物多数具有较好的α1-肾上腺素受体拮抗活性.     

凝血酶蛋白酶激活受体-1作为转移性黑色素瘤治疗潜在靶点的研究进展

黑色素瘤由于转移性强,成为皮肤癌中死亡率最高的恶性肿瘤之一,目前没有有效的治疗方法。凝血酶蛋白酶激活受体-1(PAR-1)在黑色素瘤的发病过程中起到重要作用,PAR-1通过激活肿瘤细胞黏附和侵袭以及新生血管因子生成促进黑色素瘤转移。PAR-1有望成为治疗转移性黑色素瘤药物新靶点。     

抗血小板新药vorapaxar

凝血酶受体拮抗剂vorapaxar(沃拉帕沙)为新一类抗血小板药,2014年5月8日美国食品与药品监督管理局(FDA)批准其硫酸盐(商品名:Zontivity)上市,与标准抗血小板治疗药合用作为急性冠脉综合征的二级预防,可改善心梗患者血栓性心血管事件。该药在发挥疗效的同时也需关注出血的风险。文中对其药理作用、临床研究和安全性等做一综述。     

2,4-二芳基-1,3-二氧戊环化合物的合成和iNOS/PAF双重抑制活性

目的合成既拮抗PAF受体又抑制iNOS活性的化合物 ,期望能获得治疗败血性休克及有关炎症疾病的新型药物。方法以PAF受体拮抗剂 2 ,4 二芳基 1,3 二硫戊环为先导物 ,合成其生物电子等排体二氧戊环化合物 ,并在其 2位芳环上引入有iNOS抑制活性的基团 ,测定所得化合物的iNOS抑制活性和PAF受体拮抗活性。结果与结论共制备了 2 2个未见文献报道的目标化合物 ,对其中 15个进行iNOS抑制活性测试 ,发现有 3个活性与正在Ⅲ期临床研究的氨基胍相当 ,另有 3个活性强于氨基胍。对上述 6个化合物进行PAF受体抑制活性测定 ,发现 2个活性较强 ,其IC50 分别为 2 2 9× 10 -6mol/L和 2 5 7× 10 -6mol/L。     

目前和未来良性前列腺增生的药物治疗

治疗良性前列腺增生的药物有5α-还原酶抑制剂非那雄胺和α1肾上腺素能受体拮抗剂。非选择性α1-肾上腺素能受体拮抗剂原作为抗高血压药，主要副作用为低血压，可用降低峰浓度如使用每天一次的阿夫唑嗪或用尿道选择性α1-肾上腺素能受体拮抗剂坦洛新来减轻。一般不用雄激素受体拮抗剂，因其副作用较大。正在开发的较新药物有选择性α1A-肾上腺素能受体拮抗、5α-还原酸加α-肾上腺素能受体拮抗剂和Ⅰ，Ⅱ混合型5α-还原酶抑制剂。治疗良性前列腺增生的新靶标有内皮素、生长因子、雌激素和磷酸二酯酶同工酶。     

Vorapaxar: a novel protease-activated receptor-1 inhibitor

INTRODUCTION: Platelet activation and reactivity are pivotal for both acute and chronic atherothrombotic event occurrences. AREAS COVERED: Only 20% relative risk (～ 2% absolute risk) reduction associated with newer P2Y(12) receptor blocker therapy such as prasugrel and ticagrelor compared with clopidogrel indicates that dual antiplatelet therapy may be associated with a ceiling effect in attenuating platelet-mediated ischemic event occurrence and that residual ischemic event occurrences are mediated by other pathways that are unblocked by current antiplatelet therapy. Therefore, inhibition of the thrombin-protease-activated receptor (PAR)-1 interaction may provide additional benefits in attenuating ischemic event occurrence in selected patients. There are two major PAR-1 blockers are under investigations - vorapaxar and atopaxar. In preclinical and Phase I - II studies, inhibition of thrombin-mediated platelet activation by a PAR-1 inhibitor, in general, has added to the antithrombotic efficacy of aspirin and clopidogrel without increasing bleeding. However, intracranial hemorrhage in patients with a history of stroke associated with vorapaxar and hepatic toxicity associated with atopaxar are important concerns. EXPERT OPINION: At this time, the specific role of PAR-1 inhibitor in the settings of percutaneous coronary intervention and acute coronary syndrome, both during the acute setting and as a long-term therapeutic agent, is not clear. Although the PAR-1 inhibitors are associated with less bleeding, its effectiveness as an antithrombotic agent and also side effects are major concerns. Future large-scale trials with goals addressing these concerns are needed to define the specific role of PAR-1 receptor inhibitor.     

Thrombin receptor antagonists; recent advances in PAR-1 antagonist development

The receptor for the serine protease thrombin, the protease-activated receptor-1 (PAR-1), has been recently characterized. Its key roles in thrombin-stimulated human platelet activation, vascular endothelial and smooth muscle proliferation, inflammatory responses and neurodegeneration suggest receptor involvement in various disorders such as arterial thrombosis, atherosclerosis, restenosis, inflammation and myocardial infarction. It has been established that thrombin elicits the majority of its effects via PAR-1. PAR-1 has a novel mechanism of activation. The receptor, a member of the seven-transmembrane domain receptor family, is cleaved by thrombin at a specific site on the N-terminal extension, and a newly exposed N-terminus acts as a tethered ligand to activate the receptor itself. The need for development of a PAR-1 antagonist that may be valuable as a therapeutic agent has been recognized. An intriguing challenge is the necessity of the antagonist to compete with an intramolecular ligand while showing no intrinsic activity. The lead compounds were found to be synthetic peptides containing N-terminal hexapeptide or pentapeptide (Ser-Phe-Leu-Leu-Arg-Asn, Ser-Phe-Leu-Leu-Arg) or modified sequences (TRAPs; thrombin receptor-activating peptides), which exhibit full PAR-1 agonist activity. Selective PAR-1 antagonists have already been synthesized. Though their potency is still not enough to justify therapeutic use, it is clear that future progress will bring a novel class of drugs-thrombin receptor antagonists. The emphasis of this review, therefore, will be placed on advances in the discovery of potent and selective PAR-1 antagonists.     

New perspectives in antiplatelet therapy

Platelet activation is a complex mechanism of response to vascular injury and atherothrombotic disease, leading to thrombus formation. A wide variety of surface receptors -integrins, leucine-rich family receptors, G protein coupled receptors, tyrosine kinase receptors- and intraplatelet molecules support and regulate platelet activation. They are potential targets of antiplatelet therapy for the prevention and treatment of arterial thrombosis. Despite the overall clinical benefit of established antiplatelet drugs targeting cyclooxigenase-1 (COX-1), glycoprotein integrin αIIbβ3, and the purinergic P2Y(12) receptor of adenosine diphosphate, a significant proportion of treated patients continue to experience recurrent ischaemic events. This may be in partly attributed to insufficient inhibition of platelet activation. In addition, it should not be underestimated that these drugs are not immune from bleeding complications. The substantial progress in understating the regulation of platelet activation has played a key role in the development of novel antiplatelet agents. Current examples of drug under development and evaluation include: novel P2Y(12) receptor inhibitors (prasugrel, ticagrelor, cangrelor, and elinogrel), thrombin receptor PAR-1 antagonists (vorapaxar, atopaxar), new integrin glycoprotein IIb/IIIa inhibitors, and inhibitors targeting the thromboxane receptor (TP), phosphodiesterases, the collagen receptor glycoprotein VI, and intraplatelet signalling molecules. This review summarizes the mechanisms of action and current clinical evaluation of these novel antiplatelet agents.     

PAR-1 Inhibitors: A Novel Class of Antiplatelet Agents for the Treatment of Patients with Atherothrombosis

Stroke and myocardial infarction are leading causes of death and disability worldwide. Typically, these events are triggered by the rupture or erosion of "vulnerable" atherosclerotic plaque, a phenomenon termed atherothrombosis.Three platelet activation pathways are presumed to be particularly important in the genesis of atherothrombosis and are triggered by 1) cyclo-oxygenase (COX)-1 mediated thromboxane A2 (TXA2) synthesis and activation via the TXA2 receptor, 2) adenosine diphosphate (ADP) via the P2Y12 receptor, and 3) thrombin via the protease activated receptor (PAR)-1.Despite the efficacy of aspirin and of a growing family of P2Y12 receptor antagonists on the first 2 pathways, major cardiovascular events continue to occur in patients with coronary and cerebrovascular disease, suggesting that thrombin-mediated platelet activation may contribute to these adverse events.Recently, a novel class of antiplatelet agents able to inhibit thrombin-mediated platelet activation has been developed, PAR-1 inhibitors. In this chapter, we will discuss the rationale underlying the development of this novel class of agents focus on the two drugs in the most advanced stages of development: vorapaxar (SCH530348) and atopaxar (E5555).     

Therapeutic potential of protease-activated receptor-1 antagonists

The serine protease thrombin (EC 3.4.21.5) is central to the maintenance of haemostatic balance through its coagulant, anticoagulant and platelet activating properties. In addition, this enzyme affects numerous cellular responses in a wide variety of cells, such as cell proliferation, cytokine and growth factor release, lipid metabolism and tissue remodelling. A family of Gproteincoupled protease-activated receptors (PARs) mediates these cellular actions of thrombin. While thrombin can activate three of the four PAR family members, PAR-1 represents the primary thrombin-responsive receptor in human cells. The expression of PAR-1 in platelets, the vasculature and myocardium, in cells within atherosclerotic plaque and tissues after vascular injury, indicates that this receptor plays an important role during the response to tissue injury and associated inflammatory processes. With the development of PAR-deficient mice and small-molecule antagonists, it is now clear that intervening in processes mediated by PAR-1 presents a new approach to treating a variety of disorders dependent on thrombin generation, including thrombosis and restenosis. The full potential of PAR-1 antagonists has yet to be realised, but the promise of novel therapeutics that modulate receptor function rather than thrombin’s proteolytic activity, provides an alternative and, perhaps, more desirable means to dampen the pathological effects of thrombin.     

Himbacine-Derived Thrombin Receptor Antagonists: C7-Spirocyclic Analogues of Vorapaxar

相似文献   

Therapeutic potential of protease-activated receptor-1 antagonists

The serine protease thrombin (EC 3.4.21.5) is central to the maintenance of haemostatic balance through its coagulant, anticoagulant and platelet activating properties. In addition, this enzyme affects numerous cellular responses in a wide variety of cells, such as cell proliferation, cytokine and growth factor release, lipid metabolism and tissue remodelling. A family of G-protein-coupled protease-activated receptors (PARs) mediates these cellular actions of thrombin. While thrombin can activate three of the four PAR family members, PAR-1 represents the primary thrombin-responsive receptor in human cells. The expression of PAR-1 in platelets, the vasculature and myocardium, in cells within atherosclerotic plaque and tissues after vascular injury, indicates that this receptor plays an important role during the response to tissue injury and associated inflammatory processes. With the development of PAR-deficient mice and small-molecule antagonists, it is now clear that intervening in processes mediated by PAR-1 presents a new approach to treating a variety of disorders dependent on thrombin generation, including thrombosis and restenosis. The full potential of PAR-1 antagonists has yet to be realised, but the promise of novel therapeutics that modulate receptor function rather than thrombin's proteolytic activity, provides an alternative and, perhaps, more desirable means to dampen the pathological effects of thrombin.     

Oral administration of the thrombin receptor antagonist E5555 (atopaxar) attenuates intimal thickening following balloon injury in rats

Thrombin is a powerful agonist for a variety of cellular responses including platelet aggregation and vascular smooth muscle cell (SMC) proliferation. These actions are mediated by a thrombin receptor known as protease-activated receptor-1 (PAR-1). Recently we discovered that 1-(3-tert-butyl-4-methoxy-5-morpholinophenyl)-2-(5,6-diethoxy-7-fluoro-1-imino-1,3-dihydro-2H-isoindol-2-yl)ethanone hydrobromide (E5555, atopaxar) is a potent and selective thrombin receptor antagonist. This study characterized the pharmacological effects of E5555 on SMC proliferation in vitro and in a rat model of intimal thickening after balloon injury in vivo. E5555 selectively inhibited rat aortic SMC proliferation induced by thrombin and thrombin receptor-activating peptide (TRAP) with half maximal inhibitory concentration (IC(50)) values of 0.16 and 0.038 μM, respectively. E5555 did not inhibit rat SMC proliferation induced by basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) at concentrations up to 1μM. In addition, E5555 inhibited human aortic SMC proliferation induced by thrombin at concentrations of 0.3 and 3units/ml with IC(50) values of 0.028 and 0.079 μM, respectively, whereas it did not affect bFGF-induced proliferation at concentrations up to 1μM. Repeated oral administration of 30 mg/kg E5555 (once daily for 16 days) significantly reduced neointimal formation in the balloon-injured rat arterial model. These results suggested that a PAR-1 antagonist could be effective for treating restenosis following vascular intervention in addition to preventing thrombus formation. E5555 could thus have therapeutic potential for restenosis and chronic atherothrombotic disease.     

Proteinase-activated receptors

Proteinase-activated receptors are a recently described, novel family of seven-transmembrane G-protein-coupled receptors. Rather then being stimulated through ligand receptor occupancy, activation is initiated by cleavage of the N terminus of the receptor by a serine protease resulting in the generation of a new tethered ligand that interacts with the receptor within extracellular loop-2. To date, four proteinase-activated receptors (PARs) have been identified, with distinct N-terminal cleavage sites and tethered ligand pharmacology. In addition to the progress in the generation of PAR-1 antagonists, we describe the role of thrombin in such processes as wound healing and the evidence implicating PAR-1 in vascular disorders and cancer. We also identify advances in the understanding of PAR-1-mediated intracellular signaling and receptor desensitization. The cellular functions, signaling events, and desensitization processes involved in PAR-2 activation are also assessed. However, other major aspects of PAR-2 are highlighted, in particular the ability of several serine protease enzymes, in addition to trypsin, to function as activators of PAR-2. The likely physiological and pathophysiological roles for PAR-2 in skin, intestine, blood vessels, and the peripheral nervous system are considered in the context of PAR-2 activation by multiple serine proteases. The recent discovery of PAR-3 and PAR-4 as additional thrombin-sensitive PARs further highlights the complexity in assessing the effects of thrombin in several different systems, an issue that remains to be fully addressed. These discoveries have also highlighted possible PAR-PAR interactions at both functional and molecular levels. The future identification of other PARs and their modes of activation are an important future direction for this expanding field of study.