Inhibitors of Anthrax Lethal Factor Metalloproteinase

描述（由申请人提供）：炭疽致死因子（LF）是一种在炭疽杆菌感染期间引入哺乳动物宿主细胞的金属蛋白酶。LF破坏由MAPKK介导的细胞内信号传导途径，导致细胞毒性、败血症、呼吸衰竭和快速死亡。虽然在症状出现后的前48小时内给予抗生素治疗是有效的，但如果在这个狭窄的治疗窗口后开始，它不能预防死亡。虽然接触这种病原体的程度有限，但炭疽孢子作为生物恐怖主义武器的致命性在2001年通过美国邮件进行的袭击中得到了证明。需要能够抑制LF毒性作用的新疗法来对抗晚期疾病。目前的治疗方法，如抗生素，疫苗和生物疗法的发展，遭受显着的缺点。它们的共同点是无法保护细胞免受LF的直接影响。这些疗法也容易受到利用LF毒性的下一代转基因武器的攻击。直接靶向LF活性可能与目前的治疗方法产生协同作用，并且是唯一提出的可以在晚期感染期间提供拯救的炭疽治疗方法。LF抑制剂的使用最近已在动物中被验证为治疗方法。然而，迄今为止，没有报道的LF抑制剂具有能够在大规模生物恐怖主义炭疽袭击事件中保护普通人群的药物所需的特性。夏威夷生物技术公司目前的战略是，(HBI)使用设计用于鉴定在炭疽感染动物模型中具有良好PK性质和功效的有效LF抑制剂的测定法，采用三层筛选级联。实现这一目标将需要继续优化药物化学的抑制剂在HBI发现，以及新的铅系列的识别。在HBI开发的计算高通量对接协议，并专门针对LF定制，将用于发现新的抑制剂作为我们当前线索的备份。化合物的体外特征分析以评估LF的效力和选择性，沿着先导系列的分子建模将指导效力优化。HBI制备的一组独特的LF突变体也将用于指导新型LF抑制剂的设计和优化。将确定强效抑制剂的理化性质、PK和ADMET特征，以选择最佳候选药物进行体内试验。最后，将在已建立的炭疽感染动物模型中证明潜在临床前候选药物的疗效。在第二阶段更新中提出的工作将建立在HBI的LF作为药物靶点的专业知识的基础上，目标是确定一种口服生物可利用的临床前候选药物，该药物在炭疽致死因子中毒的暴露后动物模型中显示出体内疗效。2001年的生物恐怖主义袭击通过美国邮件传递炭疽孢子，导致11例确诊病例，5人死亡。目前缺乏有效的治疗接触炭疽热的方法，使这种不幸的悲剧重演成为真实的可能性。这项研究的目的是确定一种药物，将保护公众免受任何未来的生物恐怖主义行为使用炭疽作为武器。

DESCRIPTION (provided by applicant): Anthrax Lethal Factor (LF) is a metalloproteinase introduced into the cells of mammalian hosts during infection by the bacterium Bacillus anthracis. LF disrupts intracellular signaling pathways mediated by the MAPKKs, resulting in cell toxicity, sepsis, respiratory failure and rapid death. While antibiotic therapy is effective if given in the first 48 h after symptoms appear, it cannot prevent death if initiated after this narrow therapeutic window. Although exposure to this pathogen is limited in nature, the lethality of anthrax spores as a bioterrorism weapon was demonstrated in the 2001 attacks through the US mail. Novel therapeutics capable of inhibiting the toxic effects of LF are needed to combat late-stage disease. Current treatment methods such as antibiotics, vaccines, and biologic therapies in development, suffer from significant drawbacks. Common to each is an inability to protect cells from the direct effects of LF. These therapies are also vulnerable to next generation genetically modified weapons exploiting LF toxicity. Directly targeting LF activity may allow synergy with current therapies and is the only proposed method of anthrax therapy that may provide rescue during late-stage infection. Use of an LF inhibitor has recently been validated in animals as a therapeutic approach. To date, however, no reported LF inhibitors possess the characteristics needed for a drug capable of protecting the general population in the event of a large scale bioterrorism anthrax attack. The current strategy at Hawaii Biotech Inc. (HBI) employs a three tiered screening cascade using assays designed to identify potent LF inhibitors with good PK properties and efficacy in animal models of anthrax infection. Achievement of this goal will require the continued medicinal chemistry optimization of inhibitors discovered at HBI as well as the identification of new lead series. Computational high throughput docking protocols developed at HBI and tailored specifically towards LF will be used to discover new inhibitors as backups to our current leads. In vitro profiling of compounds to assess potency and selectivity for LF along with molecular modeling of lead series will guide potency optimization. A unique panel of LF mutants prepared at HBI will also be used to guide the design and optimization of novel LF inhibitors. The physicochemical properties, PK, and ADMET characteristics of potent inhibitors will be determined to allow selection of the best candidates for in vivo testing. Finally, the efficacy of potential pre-clinical candidates will be demonstrated in established animal models of anthrax infection. The work proposed in this Phase II Renewal will build on HBI's expert knowledge of LF as a drug target with the goal of identifying an orally bioavailable preclinical candidate that demonstrates in vivo efficacy in a post-exposure animal model of anthrax lethal factor intoxication. The 2001 bioterrorism attack which delivered anthrax spores through the US mail resulted in eleven confirmed cases of the disease and led to five deaths. The current lack of an effective treatment for exposure to anthrax makes a repeat this unfortunate tragedy a real possibility. The goal of this research is to identify a drug which will protect the general public from any future acts of bioterrorism using anthrax as a weapon.