Targeting trypanosomatid deoxyhypusine synthase

项目描述。 锥虫寄生虫是人类非洲锥虫病（HAT）的病原体， 利什曼病和恰加斯病，均被世界卫生组织列为被忽视的热带病 （NTD）。总共有1800万至2000万人感染了这些寄生虫之一，但药物治疗 对所有三种疾病来说都是不够的。发现了一种可以用来对付所有人的药物靶点 三种寄生虫，虽然没有显示出对宿主的毒性，但将提供一种强大的新方法， 对抗这些疾病。真核生物普遍需要一种称为eIF5A的翻译因子来进行细胞生长。 为了具有活性，eIF5A必须在保守的赖氨酸残基上进行后修饰，以产生一种新的活性。 一种叫做羟腐胺赖氨酸的新氨基酸eIF5A的羟腐胺赖氨酸修饰由脱氧羟腐胺赖氨酸催化 合成酶（DHS）使用亚精胺作为底物。DHS是所有真核生物中的必需酶，包括 锥虫我们以前证明，从锥虫和内阿米巴DHS有 独特地进化到需要在两个旁系同源基因产物之间形成异源四聚体以产生 活性酶。这些寄生虫DHS的这种不寻常的配置表明， 确定寄生虫酶的选择性抑制剂，这些酶不抑制人类DHS。这个目标 建议是确定是否有选择性的锥虫酶的DHS药物样抑制剂 如果是，则在用于治疗HAT的导联优化程序期间推进它们。 在该提案的R21阶段，我们计划开发一种高通量筛选（HTS）兼容的检测方法 对于T.布氏锥虫DHS，并使用该测定筛选UT西南200，000化合物库中的T. 布鲁氏菌DHS抑制剂。我们将对识别出的抑制剂进行命中验证，并确定 鉴定的抑制剂显示出对人DHS的良好选择性。如果锥虫特异性DHS 与我们计划的R33阶段相比，可以确定具有良好药物样特性的抑制剂 一个命中，以导致优化至少一个系列与适当的属性，以提前为 HAT的治疗已确定的DHS抑制剂也将在命中验证期间的各个阶段进行测试 并针对T. cruzi和利什曼原虫，以确定它们是否有潜力成为 作为所有三种锥虫疾病的广谱治疗方法而开发。

Project Description. Trypanosomatid parasites are the causative agents of human African trypanosomiasis (HAT), Leishmaniasis and Chagas disease, all of which are listed by the WHO as Neglected tropical diseases (NTDs). Collectively 18-20 million people are infected with one of these parasites, yet drug therapies remain inadequate for all three diseases. Discovery of a drug-target that could be exploited against all three parasites, while not showing toxicity against the host, would provide a robust new approach to combat these diseases. Eukaryotes universally require a translation factor called eIF5A for cell growth. To be active eIF5A must be post-translationally modified on a conserved lysine reside to generate a novel amino acid called hypusine. The hypusine modification of eIF5A is catalyzed by deoxyhypusine synthase (DHS) using spermidine as a substrate. DHS is an essential enzyme in all eukaryotes including the trypanosomatids. We previously demonstrated that DHS from trypanosomatids and Entamoeba have uniquely evolved to require heterotetramer formation between two paralogous gene products to generate the active enzyme. This unusual configuration of these parasite DHSs suggests that it may be feasible to identify selective inhibitors of the parasite enzymes that don't inhibit human DHS. The goal of this proposal is to determine if drug-like inhibitors of DHS that are selective for the trypanosomatid enzymes can be identified and if so to advance them during a lead optimization program for the treatment of HAT. In the R21 phase of this proposal we plan to develop a high throughput screen (HTS) compatible assay for T. brucei DHS and to use this assay to screen the UT Southwestern 200,000 compound library for T. brucei DHS inhibitors. We will perform hit validation on identified inhibitors and determine if the identified inhibitors show good selectivity versus human DHS. If trypanosomatid specific DHS inhibitors with good drug like properties can be identified than in the R33 phase of the proposal we plan a hit to lead optimization of at least one series with appropriate properties to be advanced for the treatment of HAT. Identified DHS inhibitors will also be tested at various stages during hit validation and lead optimization against T. cruzi and Leishmania to determine if they have the potential to be developed as a broad-spectrum treatment for all three trypanosomatid-based diseases.