The Evolution of Malerial Antifiolate Resistance

男性抗丝虫药物耐药性的演变

• 批准号: 7356015
• 负责人: Daniel L HARTL
• 金额: $ 31.73万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7356015
• 关键词: Africa; African; Alleles; Amino Acids; Antimalarials; Apicomplexa; Attention; Automobile Driving; Binding; Biochemical; Biological Assay; Child; Class; Clinical Management; Coupled; Data; Depth; Development; Dihydrofolate Reductase; Dihydropteroate Synthase; Disease; Dissection; Drug Delivery Systems; Drug Design; Drug resistance; Drug usage; Effectiveness; Enzymes; Escherichia coli; Event; Evolution; Falciparum Malaria; Folate; Folic Acid Antagonists; Frequencies; Future; Genealogy; Genes; Genetic; Health; In Vitro; Individual; Infection; Knowledge; Laboratory culture; Lactamase; Language; Lead; Light; Malaria; Mediating; Medical Surveillance; Methodology; Methods; Missense Mutation; Modeling; Molecular; Molecular Biology; Monobactams; Mutation; Natural Selections; Numbers; Organism; Outcome; Parasites; Pathway interactions; Pattern; Pharmaceutical Preparations; Phenotype; Plasmodium falciparum; Probability; Process; Property; Proteins; Protocols documentation; Reagent; Research; Research Personnel; Research Project Grants; Resistance; Saccharomyces cerevisiae; Sampling; Structure; System; Systems Biology; Work; base; combinatorial; design; epidemiological model; fitness; improved; in vivo; innovation; insight; interest; mortality; mutant; novel; programs; protein folding; protein structure function; resistance mechanism; response; structural biology; tool; Africa; African; Alleles; Amino Acids; Antimalarials; Apicomplexa; Attention; Automobile Driving; Binding; Biochemical; Biological Assay; Child; Class; Clinical Management; Coupled; Data; Depth; Development; Dihydrofolate Reductase; Dihydropteroate Synthase; Disease; Dissection; Drug Delivery Systems; Drug Design; Drug resistance; Drug usage; Effectiveness; Enzymes; Escherichia coli; Event; Evolution; Falciparum Malaria; Folate; Folic Acid Antagonists; Frequencies; Future; Genealogy; Genes; Genetic; Health; In Vitro; Individual; Infection; Knowledge; Laboratory culture; Lactamase; Language; Lead; Light; Malaria; Mediating; Medical Surveillance; Methodology; Methods; Missense Mutation; Modeling; Molecular; Molecular Biology; Monobactams; Mutation; Natural Selections; Numbers; Organism; Outcome; Parasites; Pathway interactions; Pattern; Pharmaceutical Preparations; Phenotype; Plasmodium falciparum; Probability; Process; Property; Proteins; Protocols documentation; Reagent; Research; Research Personnel; Research Project Grants; Resistance; Saccharomyces cerevisiae; Sampling; Structure; System; Systems Biology; Work; base; combinatorial; design; epidemiological model; fitness; improved; in vivo; innovation; insight; interest; mortality; mutant; novel; programs; protein folding; protein structure function; resistance mechanism; response; structural biology; tool

DESCRIPTION (provided by applicant): Since 1990 mortality from Plasmodium falciparum malaria has increased, due primarily to the spread of drug-resistant parasites. Although antifolates are affordable and still clinically effective, their use has been compromised by the evolution of drug resistance. Resistance results from a small number of amino acid replacements in two enzymes for folate synthesis: dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS). An understanding of the likely order in which these mutations were selected, as well as the resistance phenotypes of the intermediates and the biophysical basis of the resistance, would be important in prolonging the useful therapetic lifetime of antifolates and in developing novel and more effective antifolates. We have developed and verified a method for inferring the likely sequence of events in the evolution of drug resistance. The method also reveals the molecular mechanisms of resistance. We construct all possible combinations of relevant mutations, and assay each allele for its effect on the drug resistance phenotype of the organism and for its biochemical and biophysical properties. These data reveal the probability of each individual step in all possible genealogies of drug resistance, and hence the overall probability of each evolutionary pathway. Our previous work in another experimental system indicates that most of the probability comes from a small number of evolutionary pathways. Our experimental approach is ideally suited for dissecting the evolutionary pathways and biophysical basis' of the multiple antifolate mutations in DHFR. We therefore propose to construct all possible combinations of clinically important P. falciparum DHFR mutations. The resistance phenotype of each mutant combination will be assayed using the expression system in S. cerevisiae, and the biochemical and biophysical properties of each protein determined. Based on these data, a systems-level model will be developed that relates increased drug resistance to the biochemical and biophysical properties of the evolutionary intermediates. For future work, we will also take steps to develop an analogous DHPS system. This research has the potential to improve methods of resistance surveillance in the field, to provide basic information required for improved epidemiological modeling and drug deployment protocols, and to contribute fundamental insights1- into the rational design of novel antifolate drugs. LAY LANGUAGE SUMMARY: Drug-resistant malaria is an ever increasing problem. This year about 1.5 million African children will die from the disease. This research project will uncover why certain mutations in a particular gene contribute to resistance to a key affordable class of antimalaria drugs, the antifolates. The research may prolong the effectiveness of present antifolates, and help in the development of new ones.

描述（由申请人提供）：自1990年以来，恶性疟原虫疟疾的死亡率已增加，这主要是由于抗药性寄生虫的传播。尽管抗染料是负担得起的，并且仍然在临床上有效，但耐药性的演变却损害了它们的使用。耐药性是由两种酶中的少量氨基酸替代物进行的叶酸合成：二氢叶酸还原酶（DHFR）和二氢翅目合成酶（DHPS）。对选择这些突变的可能顺序以及中间体的耐药表型和抗性的生物物理基础的理解对于延长有用的抗样物的有用治疗寿命以及发展新颖和更有效的抗染料将很重要。我们已经开发并验证了一种推断耐药性进化中可能事件序列的方法。该方法还揭示了抗性的分子机制。我们构建了相关突变的所有可能组合，并测定每个等位基因对生物体耐药性表型及其生化和生物物理特性的影响。这些数据揭示了在耐药性的所有可能谱系中，每个单个步骤的概率，因此揭示了每个进化途径的总体概率。我们以前在另一个实验系统中的工作表明，大多数概率来自少数进化途径。我们的实验方法非常适合于DHFR中多个抗叶酸突变的进化途径和生物物理基础。因此，我们建议构建临床上重要的恶性疟原虫DHFR突变的所有可能组合。将使用酿酒酵母中的表达系统以及确定每种蛋白质的生化和生物物理特性测定每个突变体组合的抗性表型。基于这些数据，将开发系统级模型，该模型将耐药性增加与进化中间体的生化和生物物理特性有关。对于将来的工作，我们还将采取步骤开发类似的DHP系统。这项研究有可能改善该领域的耐药性监视方法，提供改善流行病学建模和药物部署方案所需的基本信息，并为新型抗叶酸药物的合理设计提供基本的见解1。外行语言摘要：耐药疟疾是一个越来越多的问题。今年，大约有150万非洲儿童将死于这种疾病。该研究项目将揭示为什么特定基因中的某些突变有助于对关键的负担得起的抗疟疾药物，抗冻剂的抗性。该研究可能会延长当前抗臭虫的有效性，并有助于开发新的抗臭虫。