Aptamer therapeutic for safe and low-cost treatment of snake bite envenomation

在美国和世界范围内，蛇咬伤毒化是一个严重的问题，其可导致大量的发病率，甚至死亡。 死亡蛇毒含有复杂的毒素混合物，包括神经毒素和肌肉毒素，以及 破坏正常的止血并可产生致命的出血。蛇毒还包括几类消化和 蛋白水解酶是负责广泛的局部组织破坏，从蛇咬伤，可导致 永久性残疾或需要截肢。目前的抗蛇毒血清产品由马体内产生的抗体片段组成 或绵羊，并且通常对稳定毒液蛰入患者有效，然而它们具有几个局限性， 它们不是对所有种类的N.美洲毒蛇在减轻组织损伤方面， 如血清病、超敏反应和复发性凝血病的影响。此外，基于抗体的制剂具有 成本极高，每名患者的治疗费用从20，000美元到40，000美元不等。 我们建议开发一种基于高亲和力适体的新型抗蛇毒血清治疗剂，该适体由单链 寡脱氧核苷酸形成茎环结构以结合其靶标。我们专有的X-Aptamer选择 该技术利用基于珠的寡DNA组合文库，其中某些碱基含有蛋白质样侧 修饰以增强结合亲和力。在这个项目中，我们将针对一组主要的毒素类生成X-适体 发现在N。美国毒蛇，以开发新的抗蛇毒制剂，具有更好的安全性比目前的 抗体抗蛇毒血清我们的初步研究已经证明了选择能够中和 来自南太平洋响尾蛇（C. O. Helleri）在小鼠的后肢麻痹模型中。 本项目的目标是：1）制备针对五类主要N.美国 蛇毒毒素，并测量每个X-适体及其靶毒素的解离常数; 2）体内证明 X-适体对蛇毒毒素和粗毒的效力，使用出血活性、肌酸 激酶活性、后肢麻痹和致死率，以确定每种适体的有效剂量; 以及在大鼠中用混合的适体抗蛇毒血清制剂进行的毒理学研究。这些研究的完成将 证明基于适体的新型制剂的安全性和有效性，这将产生强大的影响和市场潜力 毒蛇咬伤的紧急治疗

Snake bite envenomation is a significant problem in the US and worldwide that can result in substantial morbidity and even death. Snake venom contains a complex mixture of toxins including neurotoxins and myotoxins, as well as toxins that disrupt normal hemostasis and can produce fatal hemorrhage. Snake venoms also include several classes of digestive and proteolytic enzymes that are responsible for the extensive local tissue destruction from snake bites that can result in permanent disability or require limb amputation. Current antivenom products consist of antibody fragments raised in horses or sheep and are generally effective at stabilizing envenomation patients, however they come with several limitations in that they are not effective against all species of N. American venomous snakes in mitigating tissue damage, and there are adverse effects such as serum sickness, hypersensitivity, and recurrent coagulopathy. In addition, antibody-based formulations have an extremely high cost, with the cost of the drug ranging from $20,000 to $40,000 per patient treatment. We propose to develop a novel antivenom therapeutic based on high-affinity aptamers, which consist of single-stranded oligodeoxynucleotides that form stem-loop structures to bind to their targets. Our proprietary X-Aptamer selection technology utilizes bead-based oligo DNA combinatorial libraries in which certain bases contain protein-like side modifications to enhance binding affinity. In this project, we will generate X-Aptamers against a set of major toxin classes found in N. American venomous snakes, to develop novel antivenom formulation with a better safety profile than current antibody-based antivenoms. Our preliminary studies have demonstrated selection of aptamers capable of neutralizing myotoxin from Southern Pacific rattlesnakes (C. o. helleri) in a hind limb paralysis model in mice. The project aims are: 1) Generate high-affinity oligonucleotide X-Aptamers against the five major classes of N. American snake venom toxins and measure the dissociation constant for each X-Aptamer and its target toxin; 2) Demonstrate in vivo efficacy of X-Aptamers against snake venom toxins and crude venom, using mouse models of hemorrhagic activity, creatine kinase activity, hind-limb paralysis, and lethality, to determine the effective dose for each aptamer; 3) Perform dose-ranging and toxicology studies in rats with the blended aptamer antivenom formulation. The completion of these studies will demonstrate safety and efficacy of a novel aptamer-based formulation which will have a strong impact and market potential in the emergency treatment of snake bite envenomation.