Abstract：
Current treatment of snakebite relies on immunoglobulin-rich antivenoms. However, production of these antivenoms is complicated and costly. Aptamers - single-stranded DNAs or RNAs with specific folding structures that bind to specific target molecules - represent excellent alternatives or complements to antibody-based therapeutics. However, no studies have systematically assessed the feasibility of using aptamers to mitigate venom-induced toxicity in vivo. β-bungarotoxin is the predominant protein responsible for the toxicity of the venom of Bungarus multicinctus, a prominent venomous snake inhabiting Taiwan. In this study, we reported the screening and optimization of a DNA aptamer against β-bungarotoxin and tested its utility in a mouse model. After 14 rounds of directed evolution of ligands by exponential enrichment, an aptamer, called BB3, displaying remarkable binding affinity and specificity for β-bungarotoxin was obtained. Following structural prediction and point-modification experiments, BB3 underwent truncation and was modified with 2\'-O-methylation and a 3\'-inverted dT. This optimized aptamer showed sustained, high-affinity binding for β-bungarotoxin and exhibited remarkable nuclease resistance in plasma. Importantly, administration of this optimized aptamer extended the survival time of mice treated with a lethal dose of β-bungarotoxin. Collectively, our data provide a compelling illustration of the potential of aptamers as promising candidates for development of recombinant antivenom therapies.
摘要：
目前毒蛇咬伤的治疗依赖于富含免疫球蛋白的抗血清。然而,这些抗蛇毒血清的生产既复杂又昂贵。适体-具有与特定靶分子结合的特定折叠结构的单链DNA或RNA-代表了基于抗体的疗法的极好的替代或补充。然而,尚未有研究系统地评估使用适体减轻毒液体内毒性的可行性.β-银环蛇毒素是导致银环蛇毒液毒性的主要蛋白质，居住在台湾的一种突出的毒蛇。在这项研究中,我们报道了针对β-银环蛇毒素的DNA适体的筛选和优化，并测试了其在小鼠模型中的实用性。在通过指数富集对配体进行14轮定向进化后，适体,称为BB3，对β-银环蛇毒素具有显着的结合亲和力和特异性。在结构预测和点修饰实验之后，BB3经历了截断，并用2'-O-甲基化和3'-反向dT修饰。这种优化的适体显示出持续的，对β-银环蛇毒素的高亲和力结合，并在血浆中表现出显着的核酸酶抗性。重要的是,这种优化的适体的施用延长了用致死剂量的β-银环蛇毒素治疗的小鼠的存活时间。总的来说，我们的数据为适体作为开发重组抗蛇毒血清疗法的有希望的候选者提供了令人信服的例证.
