PROTOZOAN PURINE PHOSPHORIBOSYLTRANSFERASES AS TARGETS TO TREAT MALARIA, AFRICAN TRYPANOSOMIASIS AND CHAGAS'S DISEASE

原生动物嘌呤磷酸核糖基转移酶作为治疗疟疾、非洲锥虫病和恰加斯病的靶标

基本信息

批准号：
9981613
负责人：
Thomas Meek
金额：
$ 102.08万
依托单位：
TEXAS A&M AGRILIFE RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-25 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9981613
关键词：
Active Sites Adopted African African Trypanosomiasis Anabolism Animal Model Aotus primate Binding Bioavailable Catalysis Cell Culture Techniques Cells Central America Chagas Disease Chemistry Complex Crystallization Cultured Cells Development Development Plans Diphosphates Disease Drug Design Drug Kinetics Electrostatics Enzyme Inhibitor Drugs Enzymes Exhibits Gene Expression Gene Silencing Generations Genes Goals Gout Guanine HPRT1 gene Human Hypoxanthine Phosphoribosyltransferase Hypoxanthines In Vitro Infection Isotopes Kinetics Lead Malaria Maps Measurement Mediating Medical Methodology Molecular Molecular Conformation Molecular Target Morbidity - disease rate Mus Nucleosides Nucleotides Outcome Parasites Pathway interactions Permeability Pharmaceutical Preparations Phenotype Physiological Plasmodium Plasmodium falciparum Prodrugs Proteins Protozoa Purine Nucleosides Purine-Nucleoside Phosphorylase Purines Purinones Reaction Recombinants Reporting Research Ribose Roentgen Rays Sleep South America Specificity Structure Synthesis Chemistry T-Lymphocyte Technology Texas Therapeutic Agents Thermodynamics Time Toxic effect Transferase Treatment Efficacy Trypanosoma Trypanosoma brucei brucei Trypanosoma brucei gambiense Trypanosoma cruzi United States National Institutes of Health Vaccines Virulent X-Ray Crystallography Xanthines analog base chemical synthesis comparative computational chemistry design drug candidate drug development efficacy testing enzyme structure frontier human disease hypoxanthine-guanine-xanthine phosphoribosyltransferase in vivo inhibitor/antagonist inorganic phosphate metabolic phenotype mouse model nanomolar neglected tropical diseases next generation novel novel therapeutics pathogen phosphonate programs quantum chemistry safety testing serinol theories xanthosine monophosphate

项目摘要

PROJECT SUMMARY/ABSTRACT Parasitic protozoa rely on purine salvage pathways for which the enzyme hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT; hereafter, purine phosphoribosyltransferase (PPRT)) is essential. The genus Trypanosoma causes debilitating human diseases of high morbidity. Neither vaccines nor useful therapies exist. Trypanosoma cruzi causes Chagas’s Disease in Central and South America, with over 40 cases recently reported in Texas. Trypanosoma brucei rhodosiense and Trypanosoma brucei gambiense cause African sleeping sickness. Parasitic protozoa including T. cruzi and T. brucei are incapable of purine biosynthesis de novo and make nucleotides and nucleosides by purine salvage pathways. PPRT catalyzes the formation of GMP, IMP, and XMP from 5-phospho-ribose 1-pyrophosphate (PRPP) and the respective bases, guanine, hypoxanthine, and xanthine. Plasmodium falciparum, causes the most virulent form of malaria, and is also a purine auxotroph for which the action of PPRT is the only physiological path for hypoxanthine incorporation into the nucleotide pool. Transition-state analogue inhibitors (TSAIs) based on transition states for related phosphoribosyltransferases are inhibitors of P. falciparum PPRT. Cell-permeable prodrugs blocked the proliferation of P. falciparum in culture and showed selectivity vs. human HGPRT, despite the high structural similarity and active-site conservation of the enzymes. This research will design, synthesize, and characterize both in vitro and in vivo novel inhibitors of the PPRTs from P. falciparum, T. brucei ssp. and T. cruzi. Transition-state methodology, quantum computational chemistry, X-ray structure-based inhibitor design and expert chemical synthesis will be used for inhibitor development. Existing lead compounds of sub-nanomolar potency for PPRT from P. falciparum will initiate and inform our inhibitor program. Crystal structures have been reported for T. cruzi PPRT, but no potent inhibitors have been defined. No inhibitor development for T. brucei has been reported, and PPRTs have not been kinetically characterized from T. brucei. The generation of new lead compounds is anticipated to proceed rapidly for P. falciparum PPRT and emerge for Trypanosoma PPRTs once the transition-state structures of these enzymes have been solved. Optimized inhibitors which bind each of the target PPRTs will be evaluated by X-ray crystallography, to provide a refinement guide for chemistry. Potent and selective (vs. human HGPRT) inhibitors of the PPRTs will be evaluated in cell cultures of P. falciparum, T. cruzi, and T. brucei ssp for parasiticidal activity. The most effective of these will be evaluated in murine models of Malaria, Chagas’s disease and African sleeping sickness. Importantly, a successful outcome from this proposal could lead to new therapeutic agents to treat three diseases which comprise unmet or under-met medical needs. This development plan uses transition state theory to meet the NIH goals of reducing the lead time for drug development.

项目摘要/摘要寄生原生动物依赖于购买酶低黄嘌呤 - 黄甘氨酸 - 黄甘氨酸的拯救途径磷酸贝糖基转移酶（HGXPRT; Herelafter，嘌呤磷脂基转移酶（PPRT））至关重要。这锥虫属导致高发病率的人类疾病使人衰弱。疫苗也不有用存在疗法。克鲁兹锥虫在中美洲和南美引起chagas病，超过40 最近在德克萨斯州报告的案件。 Brucei Rhodosiense和Brucei gambiense锥虫瘤导致非洲昏睡病。寄生原生动物，包括克鲁齐和布鲁氏菌，无能力从头开始生物合成，并通过纯净的挽救途径使核苷酸和核苷。 PPRT催化从5-磷酸 - 核糖1-磷酸盐（PRPP）和各个碱基的GMP，IMP和XMP形成鸟嘌呤，低黄嘌呤和黄嘌呤。恶性疟原虫会引起最毒的疟疾形式，是这也是PPRT作用的嘌呤合子，是甲明氨酸的唯一物理路径掺入核苷酸池。基于过渡状态的过渡状态模拟抑制剂（TSAI）对于相关的磷酸贝糖基转移酶是恶性疟原虫PPRT的抑制剂。细胞渗透的前药被阻塞恶性疟原虫在培养中的扩散，并显示了选择性与人类HGPRT，dospite高酶的结构相似性和主动位置保守。这项研究将设计，合成和表征体外和体内新型PPRT的抑制剂来自P. falciparum，T。BruceiSsp。和T. Cruzi。过渡状态方法，量子计算化学，基于X射线结构的抑制剂设计和专家化学合成将用于抑制剂发展。恶性疟原虫的PPRT的现有铅化合物将启动并通知我们的抑制剂计划。据报道了Cruzi Pprt的晶体结构，但没有潜在的抑制剂已定义。尚未报告针对布鲁氏菌的抑制剂开发，并且PPRT尚未动力学从T. Brucei表征。预计新的铅化合物的产生将继续一旦成为过渡状态的结构这些酶已经解决。将评估结合每个目标PPRT的优化抑制剂通过X射线晶体学，为化学提供了改进指南。有力和选择性（与人类 HGPRT）PPRT的抑制剂将在恶性疟原虫，T。Cruzi和T. Brucei SSP的细胞培养物中进行评估用于寄生活性。这些最有效的方法将在Chagas的疟疾鼠模型中进行评估疾病和非洲昏睡病。重要的是，该提议的成功结果可能导致新的治疗药物治疗三种疾病，包括未满足或未满足的医疗需求。这发展计划使用过渡状态理论来满足减少毒品交货时间的NIH目标发展。