Department of Pharmacology, Nanjing Medical University, 140 Han Zhong Rd., Nanjing, Jiangsu 210029, PR China.
Eur J Pharm Sci. 2012 Apr 11;45(5):552-8. doi: 10.1016/j.ejps.2011.12.001. Epub 2012 Jan 21.
Platelets play a key role in hemostasis and in the initiation and propagation of thrombus formation. New peptide pGlu-Asn-Trp (pENW), initially extracted from snake venom, shows a concentration-dependent antithrombotic activity, significantly attenuated thrombus formation in the arterial and venous vessel systems. This study was designed to further reveal the mechanisms underlying its antithrombotic effect by focusing on its in vitro antiplatelet effect after precluding its influence on coagulation factors. It showed that pENW concentration-dependently inhibited ADP-, collagen- and platelet activating factor (PAF)-induced platelet aggregation, inversely depending upon the intensity of stimulation induced by agonists. Furthermore, data obtained by ELISA and flow cytometry presented that pENW also suppressed ADP-mediated serotonin secretion and P-selectin expression in a concentration-dependent manner. As shown by Western blot assay, ADP-induced platelet Akt phosphorylation was attenuated by the priming incubation with pENW, demonstrating the influence on platelet intracellular signaling. It provided the explaining information for its activity of inhibiting platelet activation in vitro. These results suggested pENW attenuated thrombus formation in part by inhibiting platelet activation instead of coagulation factors, presented evidence of pENW interfering intracellular signaling system in the process of platelet activation and indicated the possibility that pENW could potentially be developed as a novel therapeutic agent in the prevention and treatment of thrombotic disorders.
血小板在止血以及血栓形成的启动和传播中起着关键作用。最初从蛇毒中提取的新肽 pGlu-Asn-Trp（pENW）表现出浓度依赖性的抗血栓活性，可显著减弱动脉和静脉血管系统中的血栓形成。本研究旨在通过关注其在排除对凝血因子影响后的体外抗血小板作用，进一步揭示其抗血栓作用的机制。结果表明，pENW 浓度依赖性地抑制 ADP、胶原和血小板激活因子（PAF）诱导的血小板聚集，其抑制强度取决于激动剂诱导的刺激强度。此外，ELISA 和流式细胞术获得的数据表明，pENW 还可呈浓度依赖性地抑制 ADP 介导的 5-羟色胺分泌和 P-选择素表达。Western blot 检测结果表明，pENW 通过预孵育可减弱 ADP 诱导的血小板 Akt 磷酸化，表明其对血小板细胞内信号转导的影响。这些结果为其体外抑制血小板激活的活性提供了解释信息。这些结果表明，pENW 通过抑制血小板激活而不是凝血因子来减轻血栓形成，为 pENW 在血小板激活过程中干扰细胞内信号系统提供了证据，并表明 pENW 有可能作为预防和治疗血栓性疾病的新型治疗剂。
