NTD Highlight Notice: Melarsoprol-pentamidine cross-resistance in African trypanosomes

NTD重点公告：非洲锥虫中Melarsoprol-喷脒脒的交叉耐药性

• 批准号: MR/K000500/1
• 负责人: David Horn
• 金额: $ 38.38万
• 依托单位: University of Dundee
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FK000500%2F1
• 关键词: NTD; Highlight; Notice; Melarsoprol; pentamidine

African trypanosomes are protozoan parasites that cause a range of important human and animal diseases. Human African Trypanosomaiasis (HAT) is typically fatal without drug treatment. Transmission is via the tsetse fly and parasites then circulate in the bloodstream and tissue fluids of their mammalian hosts. The public health situation has improved recently with increased monitoring and therapy averting more than 1.3 million DALYs (Disability-Adjusted Life Years) during 2000 and cases estimated at less than 70,000 in 2006. However, therapies suffer multiple problems including severe toxicity and increasing resistance, a major concern due to the absence of a vaccine or therapeutic alternatives. The only current HAT therapies in most cases are pentamidine, which is only suitable for the first stage of the disease prior to central nervous system involvement, and melarsoprol for advanced disease. Melarsoprol contains arsenic and causes a fatal reactive encephalopathy in around 5% of patients. This desperate situation is made worse by the current and increasing incidence of melarsoprol treatment failures; 20-30% in Uganda, the Democratic Republic of Congo, and the Sudan. This is due to the spread of drug resistance. In fact, the problem is one of multi-drug resistance to both pentamidine and melarsoprol. The applicant's group recently made a breakthrough in this area and linked a defect in water and glycerol channels (aquaglyceroporins or AQPs) to melarsoprol and pentamidine cross-resistance. Further analysis indicated a central role for one particular gene, AQP2, in cross-resistance, suggesting that natural resistance may be due to reduced AQP2 expression. There is a desperate need for research that improves our understanding of melarsoprol-pentamidine cross-resistance in African trypanosomes. Clearly, an improved understanding of the mechanisms involved will be important for human health, facilitating the development of diagnostic tools and improved therapies. In addition, an understanding of how aquaglyceroporins contribute to this phenomenon will make an important contribution to basic biomedical science. The proposal aims to improve our understanding of melarsoprol-pentamidine cross-resistance and to develop a diagnostic test. Specifically, the contribution of AQP2 to drug resistance will be assessed and exploited. The first key goal is to determine how different protein sequences in AQPs influence drug sensitivity. AQPs with different sequences will be assessed using genetic manipulation followed by drug resistance assays. This will allow drug sensitivity to be assigned to a specific protein sequence combination. These sequence combinations will then be similarly examined in AQPs found naturally to develop our understanding of the relationship between AQP function and drug resistance. The goal here is to predict and test whether natural trypanosome isolates are sensitive or resistant. Another set of experiments is designed to identify the protein sequences (zip-codes) that dictate the location of the AQPs in the cell and how this impacts on drug resistance. These results will allow us to predict the behavior of naturally occurring AQPs which will be tested experimentally. Trypanosomes that have no AQP genes will also be made. A variety of assays will then be used to assess the behavior of these cells and to address the question, are AQPs themselves promising drug targets? The new knowledge will finally be translated into a diagnostic test. The test will depend upon the use of an AQP2-specific antibody or a DNA-based diagnostic. A test for the presence of AQP2 will rapidly predict the melarsoprol-pentamidine sensitivity/resistance of clinical strains and allow for the selection of the most appropriate treatment.

非洲锥虫是一种原虫寄生虫，可引起一系列重要的人类和动物疾病。非洲人类锥虫病（HAT）在没有药物治疗的情况下通常是致命的。通过采采蝇和寄生虫传播，然后在其哺乳动物宿主的血液和组织液中循环。公共卫生状况最近有所改善，加强了监测和治疗，2000年期间避免了130多万残疾调整生命年（DALYs）， 2006年的病例估计不到7万。然而，治疗方法存在多种问题，包括严重毒性和日益增加的耐药性，这是由于缺乏疫苗或治疗替代品而引起的一个主要问题。在大多数病例中，目前唯一的HAT治疗方法是喷他脒，它只适用于中枢神经系统受累前的疾病第一阶段，而美拉胂醇适用于晚期疾病。美拉胂醇含有砷，在大约5%的患者中导致致命的反应性脑病。目前越来越多的美拉胂醇治疗失败使这种绝望的情况变得更糟；乌干达、刚果民主共和国和苏丹的比例为20-30%。这是由于耐药性的扩散。事实上，问题是对喷他脒和美拉胂醇的多重耐药。申请人小组最近在该领域取得了突破，并将水和甘油通道（aquaglyceroporins或AQPs）中的缺陷与美拉胂醇和喷他脒的交叉抗性联系起来。进一步的分析表明，一个特定的基因AQP2在交叉抗性中起着核心作用，这表明自然抗性可能是由于AQP2表达减少所致。迫切需要进行研究，以提高我们对非洲锥虫对美拉胂prol-pentamidine交叉耐药的理解。显然，更好地了解所涉及的机制对人类健康非常重要，有助于开发诊断工具和改进治疗方法。此外，了解水甘油oporins是如何导致这种现象的，将对基础生物医学科学做出重要贡献。该建议旨在提高我们对美拉索prol-pentamidine交叉耐药的理解，并开发一种诊断测试。具体而言，将评估和利用AQP2对耐药的贡献。第一个关键目标是确定aqp中不同的蛋白质序列如何影响药物敏感性。不同序列的AQPs将通过基因操作进行评估，然后进行耐药性分析。这将允许将药物敏感性分配给特定的蛋白质序列组合。然后，这些序列组合将在自然发现的AQP中进行类似的检查，以加深我们对AQP功能与耐药性之间关系的理解。目的是预测和测试天然分离的锥虫是敏感的还是耐药的。另一组实验旨在确定决定aqp在细胞中位置的蛋白质序列（邮政编码），以及这对耐药性的影响。这些结果将使我们能够预测自然发生的aqp的行为，并将进行实验测试。没有AQP基因的锥虫也会被制造出来。然后将使用各种检测方法来评估这些细胞的行为，并解决aqp本身是否有希望成为药物靶点的问题？这些新知识最终将转化为诊断测试。该测试将取决于使用aqp2特异性抗体或基于dna的诊断。检测AQP2的存在将快速预测临床菌株对美拉胂醇-喷他脒的敏感性/耐药性，并允许选择最合适的治疗方法。

项目成果

Genetic dissection of drug resistance in trypanosomes.

• DOI: 10.1017/s003118201300022x
• 发表时间: 2013-10
• 期刊: Parasitology
• 影响因子: 2.4
• 作者: Alsford S;Kelly JM;Baker N;Horn D
• 通讯作者: Horn D

How Antiparasitic Drugs Work-And Sometimes Stop Working!

• DOI: 10.1371/journal.ppat.1005430
• 发表时间: 2016-05
• 期刊: PLoS pathogens
• 影响因子: 6.7
• 作者: Horn D

Chimerization at the AQP2-AQP3 locus is the genetic basis of melarsoprol-pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates.

• DOI: 10.1016/j.ijpddr.2015.04.002
• 发表时间: 2015-08
• 期刊: INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE
• 影响因子: 4
• 作者: Graf, Fabrice E.;Baker, Nicola;Munday, Jane C.;de Koning, Harry P.;Horn, David;Maeser, Pascal
• 通讯作者: Maeser, Pascal

Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense.

• DOI: 10.1007/s00018-016-2173-6
• 发表时间: 2016-09
• 期刊: Cellular and molecular life sciences : CMLS
• 作者: Graf FE;Ludin P;Arquint C;Schmidt RS;Schaub N;Kunz Renggli C;Munday JC;Krezdorn J;Baker N;Horn D;Balmer O;Caccone A;de Koning HP;Mäser P
• 通讯作者: Mäser P

Antiparasitic chemotherapy: from genomes to mechanisms.

• DOI: 10.1146/annurev-pharmtox-011613-135915
• 发表时间: 2014
• 期刊: Annual review of pharmacology and toxicology
• 影响因子: 12.5
• 作者: Horn D;Duraisingh MT
• 通讯作者: Duraisingh MT