Zavyalova Elena, Samoylenkova Nadezhda, Revishchin Alexander, Golovin Andrey, Pavlova Galina, Kopylov Alexey
Chemistry Department of Lomonosov Moscow State University, Moscow, Russian Federation; 'APTO-PHARM' LTD, Moscow, Russian Federation.
'APTO-PHARM' LTD, Moscow, Russian Federation; Institute of Gene Biology of Russian Academy of Sciences, Moscow, Russian Federation.
PLoS One. 2014 Sep 5;9(9):e107113. doi: 10.1371/journal.pone.0107113. eCollection 2014.
Aptamers are nucleic acid based molecular recognition elements with a high potential for the theranostics. Some of the aptamers are under development for therapeutic applications as promising antithrombotic agents; and G-quadruplex DNA aptamers, which directly inhibit the thrombin activity, are among them. RA-36, the 31-meric DNA aptamer, consists of two thrombin binding pharmacophores joined with the thymine linker. It has been shown earlier that RA-36 directly inhibits thrombin in the reaction of fibrinogen hydrolysis, and also it inhibits plasma and blood coagulation. Studies of both inhibitory and anticoagulation effects had indicated rather high species specificity of the aptamer. Further R&D of RA-36 requires exploring its efficiency in vivo. Therefore the development of a robust and adequate animal model for effective physiological studies of aptamers is in high current demand. This work is devoted to in vivo study of the antithrombotic effect of RA-36 aptamer. A murine model of thrombosis has been applied to reveal a lag and even prevention of thrombus formation when RA-36 was intravenous bolus injected in high doses of 1.4-7.1 µmol/kg (14-70 mg/kg). A comparative study of RA-36 aptamer and bivalirudin reveals that both direct thrombin inhibitors have similar antithrombotic effects for the murine model of thrombosis; though in vitro bivalirudin has anticoagulation activity several times higher compared to RA-36. The results indicate that both RA-36 aptamer and bivalirudin are direct thrombin inhibitors of different potency, but possible interactions of the thrombin-inhibitor complex with other components of blood coagulation cascade level the physiological effects for both inhibitors.
适配体是基于核酸的分子识别元件，在治疗诊断学方面具有很高的潜力。一些适配体正在开发用于治疗应用，作为有前景的抗血栓药物；直接抑制凝血酶活性的G-四链体DNA适配体就在其中。RA-36是一种31聚体DNA适配体，由两个通过胸腺嘧啶接头连接的凝血酶结合药效基团组成。早期研究表明，RA-36在纤维蛋白原水解反应中直接抑制凝血酶，并且还抑制血浆和血液凝固。对其抑制和抗凝作用的研究表明，该适配体具有相当高的物种特异性。RA-36的进一步研发需要探索其在体内的效率。因此，目前迫切需要开发一种强大且合适的动物模型，用于对适配体进行有效的生理学研究。这项工作致力于对RA-36适配体的抗血栓作用进行体内研究。当以1.4 - 7.1 μmol/kg（14 - 70 mg/kg）的高剂量静脉推注RA-36时，已应用血栓形成的小鼠模型来揭示血栓形成的延迟甚至预防。对RA-36适配体和比伐卢定的比较研究表明，这两种直接凝血酶抑制剂对血栓形成的小鼠模型具有相似的抗血栓作用；尽管在体外，比伐卢定的抗凝活性比RA-36高几倍。结果表明，RA-36适配体和比伐卢定都是不同效力的直接凝血酶抑制剂，但凝血酶 - 抑制剂复合物与凝血级联反应其他成分的可能相互作用使两种抑制剂的生理效应趋于平衡。
