Small Molecule Inhibitors of C. perfringens Epsilon-Toxin

说明(申请人提供)：C.产气荚膜菌表型毒素(ETX)是一种潜在的生物武器，包括在B类优先制剂清单中。这项建议的总体目标是识别并在体内测试新的ETX抑制剂，使用一种由Innovative Biologics，Inc.开发的用于灭活成孔毒素的新方法。该方法基于用与孔本身具有相同对称性的分子封闭目标孔。我们的SBIR第一阶段项目的结果表明，设计用于阻断epsilon毒素形成的跨膜通道的β-环糊精衍生物可以在低微摩尔浓度下抑制其细胞毒性。在成功完成这项可行性研究的基础上，我们建议设计、合成和筛选用于epsilon毒素活性抑制剂的β-环糊精衍生物文库，并在小鼠身上测试选定的先导化合物。本研究第二阶段的具体目的是：(1)优化β-环糊精衍生物抑制产气荚膜梭菌表观毒素细胞毒活性的检测方法。(2)结合药物化学利用初始测试数据来设计和合成对epsilon毒素孔具有增强亲和力的β-环糊精衍生物的偏向文库。(3)用细胞为基础的方法筛选文库，筛选出最有效的抑制剂，并测试它们对ETX形成的孔道的阻断能力。(4)使用至少三种化合物对小鼠进行毒性、药代动力学和药效试验，以选择体内有效的线索。从长远来看，后续的临床前和临床研究将导致针对产气荚膜梭菌epsilon毒素的新药的开发。与公共卫生相关：由产气荚膜梭菌产生的Epsilon毒素是最致命的细菌毒素之一。它被视为一种潜在的生物武器，并被列入B类优先制剂清单。目前，对5-毒素介导的中毒尚无有效的治疗方法，因此，迫切需要开发针对这种生物防御毒素的治疗方法。

DESCRIPTION (provided by applicant): C. perfringens epsilon-toxin (ETX) is a potential biological weapon included in the list of category B priority agents. The overall goal of this proposal is to identify and perform in vivo testing of new inhibitors of ETX using a novel approach for the inactivation of pore-forming toxins developed at Innovative Biologics, Inc. It is based on the blocking of the target pore with molecules having the same symmetry as the pore itself. Results from our SBIR Phase I project demonstrated that beta-cyclodextrin derivatives designed to block the transmembrane channel formed by epsilon-toxin can inhibit its cytotoxicity at low micromolar concentrations. Based on the successful completion of this feasibility study, we propose to design, synthesize and screen a library of beta-cyclodextrin derivatives for inhibitors of epsilon-toxin's activity and test selected lead compounds in mice. The specific aims of this Phase II study are: (1) Optimize the assay for testing the ability of beta-cyclodextrin derivatives to inhibit the cytotoxic activity of C. perfringens epsilon-toxin. (2) Utilize initial testing data in concert with pharmaceutical chemistry to design and synthesize a biased library of beta- cyclodextrin derivatives with an enhanced affinity to the epsilon-toxin pore. (3) Screen the library using the cell-based assay to select the most potent inhibitors and test their ability to block the pore formed by ETX. (4) Perform toxicity, pharmacokinetic and efficacy tests in mice challenged with epsilon-toxin using at least three compounds to select in vivo validated leads. In the long-term, subsequent pre-clinical and clinical studies will lead to the development of a new drug against C. perfringens epsilon-toxin. PUBLIC HEALTH RELEVANCE: Epsilon toxin produced by Clostridium perfringens is one of the most lethal bacterial toxins. It is regarded as a potential biological weapon and is included in the list of category B priority agents. Currently, there is no effective treatment for the 5-toxin-mediated intoxication; therefore, a great need exists for the development of therapeutics against this biodefense toxin.