Identification of preclinical drug candidates for the treatment of schistosomiasis

治疗血吸虫病的临床前候选药物的鉴定

• 批准号: 9813829
• 负责人: Pavel A Petukhov
• 金额: $ 49.07万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-01 至 2021-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9813829
• 关键词: Adolescent; Animal Model; Antioxidants; Binding; Binding Sites; Biochemical; Biochemistry; Biological Assay; Biological Availability; Cell Survival; Cells; Cessation of life; Chemicals; Chronic Disease; Clinical; Collaborations; Complement; Complex; Computer Assisted; Computer-Aided Design; Country; Crystallization; Development; Diagnostic; Disease; Drug Targeting; Drug resistance; Enzymes; Evolution; Funding; Glutathione Reductase; Human; In Vitro; Infection; International; Interruption; Libraries; Ligands; Liver Microsomes; Mammalian Cell; Mediator of activation protein; Medical; Metabolic; Molecular; Molecular Target; Morbidity - disease rate; Mus; Oral; Oxadiazoles; Oxidation-Reduction; Oxides; Parasite resistance; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacology; Pharmacotherapy; Phase; Plasma; Praziquantel; Praziquantel resistance; Prevalence; Property; RNA Interference; Recombinant Proteins; Research; Resistance; Schistosoma; Schistosome Parasite; Schistosomiasis; Selenocysteine; Seminal; Structure; Study models; TXN gene; Toxic effect; United States National Institutes of Health; Vertebrates; X-Ray Crystallography; analog; base; candidate selection; chemoproteomics; chemotherapy; cytotoxicity; design; disability; drug candidate; drug development; drug discovery; enzyme activity; glutaredoxin; high throughput screening; improved; in vivo; inhibitor/antagonist; innovation; iterative design; lead optimization; mouse model; neglect; new therapeutic target; next generation; novel; novel therapeutics; pharmacokinetics and pharmacodynamics; pre-clinical; small molecule; small molecule inhibitor; structural biology; thioredoxin reductase; transmission process

PROJECT SUMMARY/ABSTRACT Schistosome parasites infect 200 million people, resulting in significant morbidity and more than 200,000 deaths annually. Schistosomiasis control strategies rely almost exclusively on chemotherapy and tens of millions of people are treated with the only available drug, praziquantel (PZQ). There are no new drugs in the clinical pipeline. PZQ cure rates obtained in mass drug administration campaigns are typically less than 50%. Furthermore, with projected levels of PZQ use it is inevitable that PZQ-resistant parasites will evolve. Therefore, it is imperative to identify new drug targets and drugs for schistosomiasis treatment. We identified a highly promising drug target: the worm selenocysteine-containing enzyme thioredoxin glutathione reductase (TGR). We established that TGR is a central and essential mediator of antioxidant defenses in the worm. The antioxidant defenses of vertebrates are diversified to three independent enzymes, glutathione reductase, thioredoxin reductase, and glutaredoxin, whereas schistosomes rely solely on TGR. TGR is a chokepoint and its inhibition leads to rapid worm death in all developmental stages. In contrast, PZQ has poor activity against juvenile worms, often resulting in partial cures. We have shown that TGR is druggable, can be selectively targeted over human orthologous enzymes and that its inhibition in worms in an animal model of schistosomiasis leads to worm death. PZQ analogs are inactive, restricting analog development to avoid or counteract drug resistance. Unlike PZQ for which the mechanism of action is not known, TGR is a defined molecular target, active as a recombinant protein, with established biochemical assays amenable to rapid compound analysis, SAR, and optimization. We recently completed a multi-tiered HTS of a large compound library (>350,000 compounds), which identified >100 TGR inhibitors that were inactive against off-target, orthologous human enzymes and nontoxic to mammalian cells. The identification of these hits demonstrates that specific inhibitors of TGR can be obtained without off-target interactions and cytotoxicity. We have obtained both liganded and ligand-free crystal structures of TGR, allowing a structure based approach to hit optimization. We hypothesize that iterative medicinal chemistry optimization will yield potent and selective small molecule TGR inhibitors that will have in vivo worm killing activity. In the R21 phase our aims are to identify hits from the multi-tiered HTS with potent (< 5 µM) worm killing activity and to characterize the TGR binding site of these inhibitors by co-crystallization with TGR and crystal structure determination. In the R33 phase we propose to optimize these novel, potent TGR inhibitors using cutting-edge, structure and ligand- based computer-aided design and medicinal chemistry to improve potency, stability, and oral bioavailability. This will be complemented by X-ray crystallography and chemoproteomics using photoreactive probes to characterize molecular TGR-compound interactions. Medicinal chemistry will be informed by enzymatic analysis of TGR and orthologous human enzymes, metabolic stability, in vitro cell toxicity, and activity against ex vivo worms. Finally, select compounds will be assessed for PK/PD properties and efficacy against schistosome infections in mice. To accomplish these transformative aims, an innovative international collaboration of global experts with expertise in schistosome biochemistry and drug discovery, structural biology, computer-aided molecular design, and chemoproteomics has been assembled. The varied and synergistic expertise of the team will facilitate overcoming critical barriers to drug development. Completion of the project will identify preclinical drug-like compounds, suitable for candidate selection for schistosomiasis treatment.

项目摘要/摘要 血块寄生虫感染了2亿人，导致了大量发病率，超过200,000 每年死亡。血吸虫病控制策略几乎完全依赖于化学疗法和数十个 数以百万计的人接受了唯一可用的药物Praziquantel（PZQ）的治疗。没有新药 临床管道。大众药物管理运动中获得的PZQ治疗率通常小于50％。 此外，随着PZQ的预计水平，不可避免的是PZQ抗性寄生虫会发展。 因此，必须确定新的药物靶标和血吸虫病治疗的药物。我们确定了一个 高度有希望的药物靶标：蠕虫硒吻氨酸半胱氨酸酶硫氧还蛋白谷胱甘肽还原酶还原酶 （TGR）。我们确定TGR是蠕虫中抗氧化剂防御的中心和必不可少的介体。 脊椎动物的抗氧化剂防御能力多样化为三种独立的酶，谷胱甘肽还原， 硫氧还蛋白还原和谷蛋白，而血吸虫仅依赖于TGR。 TGR是一个扼流口， 它的抑制作用导致所有发育阶段的快速蠕虫死亡。相比之下，PZQ的活性较差 少年蠕虫，通常会导致部分治愈。我们已经证明TGR是可吸毒的，可以有选择地 针对人类直系同源酶，并且它在蠕虫中的抑制作用 血吸虫病导致蠕虫死亡。 PZQ类似物是不活跃的，限制了模拟发展以避免或 抵抗耐药性。与不知道作用机理的PZQ不同，TGR是定义的 分子靶标，作为重组蛋白的活性 复合分析，SAR和优化。我们最近完成了大型化合物的多层HTS 库（> 350,000种化合物），鉴定出> 100个TGR抑制剂，它们不参与脱离目标， 直系同源的人酶和对哺乳动物细胞的无毒。这些命中的识别证明了 TGR的特定抑制剂可以在没有靶标相互作用和细胞毒性的情况下获得。我们有 获得了TGR的配体和无配体晶体结构，从而允许基于结构的方法击中 优化。我们假设迭代药物化学优化将产生潜力和选择性 小分子TGR抑制剂将具有体内蠕虫杀伤活性。在R21阶段，我们的目标是 从具有潜在的（<5 µm）蠕虫杀伤活动的多层HTS中识别命中率，并表征TGR 通过与TGR和晶体结构确定共结晶的结合位点。在R33中 我们建议使用尖端，结构和配体 - 基于计算机辅助设计和医学化学，以提高效力，稳定性和口服生物利用度。 这将通过X射线晶体学和化学蛋白质组学使用光反应性问题来完成 表征了分子TGR-COMPOUND相互作用。药物化学将通过酶法告知 分析TGR和直系同源的人酶，代谢稳定性，体外细胞毒性以及对活性 前体内蠕虫。最后，将评估某些化合物的PK/PD特性和效率 小鼠中的血吸虫感染。为了实现这些变革性目标，创新的国际 全球专家的合作与黑素生物化学和药物发现方面的专业知识，结构性合作 已经组装了生物学，计算机辅助分子设计和化学蛋白质组学。变化和 团队的协同专业知识将促进克服药物开发的关键障碍。完成 该项目将识别类似临床前药物的化合物，适用于候选血吸虫病的选择 治疗。