Potent and Safe Inhibitors of B. anthracis Lethal Factor

炭疽芽孢杆菌致死因子的有效且安全的抑制剂

• 批准号: 7102270
• 负责人: Maurizio Pellecchia
• 金额: $ 62.08万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7102270
• 关键词: antibiotics; apoptosis; cell death; emotions; endopeptidases; enzymes; human; lead; macrophage; play; proteins; role; spores; tissue /cell culture; toxin

DESCRIPTION (provided by applicant): Potent and safe inhibitors of anthrax lethal factor: Anthrax is primarily a disease of herbivores caused by gram-positive, aerobic, spore-forming B. anthracis. Humans are accidental hosts and cases of anthrax have been reported from almost every country. The existence of antibiotic resistant bacterial strains that arise either naturally or through deliberate engineering further emphasizes the need for alternative therapeutic approaches. Vaccines are typically problematic for prophylactic treatment of large civilian groups, because the inevitable side-effects must somehow be weighed against the chances of epidemics. The progression of anthrax depends on a secreted toxin, LF (lethal factor), a protease that plays a key role in inducing apoptosis of macrophages by cleaving the specific human cell signaling proteins. Anti-toxin approaches that treat infection therapeutically by targeting LF should therefore provide a promising alternative or complement to antibiotics and vaccines. However, further research on the role of LF for the development of Anthrax therapies is hampered by the lack of potent and selective pharmacological tools. Based on these observations, a central hypothesis in our research proposal is that small organic molecules capable of blocking or reducing the activity of LF would render B. anthracis avirulent, making Anthrax disease treatable in combination with conventional antibiotics. We propose here to develop a novel series of LF inhibitors based on a multidisciplinary approach that involves fragment-based lead design, medicinal chemistry and iterative structure-based optimizations. In vitro and finally in vivo efficacy studies will be conducted on the most promising agents. Our three specific aims are: (I) To accomplish structure-based design of potent inhibitors capable of selectively blocking the LF cleavage activity without affecting human MMP enzymes. (II) To increase, through derivatizations and iterations, the selectivity, potency and safety of the selected inhibitor scaffolds. (Ill) To test the effectiveness of fine-tuned compounds in protecting the cultured cells and to identify the drug-like lead inhibitors of LF for continued drug refinement, and in vivo efficacy studies. Relevance: Inhaling B. anthracis spores causes inhalation anthrax, the most deadly form of the disease. As the disease progresses, the spores, engulfed by alveolar macrophages, germinate to generate the bacteria, which spread through the lymph nodes to the bloodstream, eventually leading to systemic fatal shock. To successfully accomplish invasion, B. anthracis has to weaken the host immune system. LF (lethal factor) is a secreted toxin that plays a key role in inducing apoptosis (cell-death) of macrophages by cleaving the specific human cell signaling proteins. Conversely, specific inhibition of LF should prevent macrophage cell-death and promote termination of the disease. The inhibitors of LF we will develop, most likely when used in combination with antibiotics, should facilitate and assure the recovery of patients who harbor the disease.

描述（由申请人提供）：炭疽致死因子的有效和安全抑制剂：炭疽主要是由革兰氏阳性、需氧、孢子形成B引起的食草动物疾病。炭疽病人类是偶然的宿主，几乎每个国家都报告了炭疽病例。天然或通过故意工程产生的抗生素抗性细菌菌株的存在进一步强调了对替代治疗方法的需要。疫苗对于大规模平民群体的预防性治疗通常是有问题的，因为不可避免的副作用必须以某种方式与流行病的可能性进行权衡。炭疽的进展取决于分泌的毒素LF（致死因子），LF是一种蛋白酶，通过切割特定的人类细胞信号蛋白在诱导巨噬细胞凋亡中起关键作用。因此，通过靶向LF治疗感染的抗毒素方法应该为抗生素和疫苗提供有希望的替代或补充。然而，由于缺乏有效和选择性的药理学工具，对LF在炭疽治疗发展中的作用的进一步研究受到阻碍。基于这些观察结果，我们的研究建议中的一个中心假设是，能够阻断或降低LF活性的小有机分子将呈现B。炭疽菌无毒，使得炭疽病可以与常规抗生素联合治疗。我们建议在这里开发一个新的系列LF抑制剂的基础上，涉及基于片段的铅设计，药物化学和迭代的基于结构的优化的多学科方法。将对最有前途的药物进行体外和最终的体内疗效研究。我们的三个具体目标是：（I）完成能够选择性阻断LF切割活性而不影响人MMP酶的有效抑制剂的基于结构的设计。(II)通过衍生化和迭代，提高所选抑制剂支架的选择性、效力和安全性。(Ill)测试微调化合物在保护培养细胞方面的有效性，并鉴定LF的药物样先导抑制剂，以进行持续的药物改进和体内功效研究。 相关性：吸入B。炭疽孢子导致吸入性炭疽病，这是最致命的疾病形式。随着疾病的发展，被肺泡巨噬细胞吞噬的孢子发芽产生细菌，细菌通过淋巴结扩散到血液中，最终导致全身致命性休克。为了成功地完成入侵，B.炭疽病会削弱宿主的免疫系统LF（致死因子）是一种分泌型毒素，其通过切割特定的人类细胞信号蛋白而在诱导巨噬细胞凋亡（细胞死亡）中起关键作用。相反，特异性抑制LF应防止巨噬细胞死亡，促进疾病的终止。我们将开发的LF抑制剂，最有可能与抗生素联合使用时，应促进并确保患有该疾病的患者的康复。