The role of Esx-3 in mediating drug resistance

Esx-3在介导耐药性中的作用

基本信息

批准号：
10457807
负责人：
Tanya Parish
金额：
$ 46.5万
依托单位：
SEATTLE CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-01-01 至 2024-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10457807
关键词：
Antibiotics Bacillus Bacteria Binding Biochemical Biochemistry Biological Biological Assay Cells Cessation of life Chemicals Complex Copper Drug Targeting Drug Tolerance Drug resistance ELF3 gene Future Genes Genomic approach Growth Homeostasis Human Infection Ionophores Ions Iron Lead Libraries Manganese Mediating Metals Microbiology Molecular Molecular Biology Mutation Mycobacterium tuberculosis Oxyquinoline Penetration Pharmaceutical Preparations Pharmacotherapy Phenotype Physiological Play Population Property Proteins Relapse Resistance Role Series Site Sterilization Structure-Activity Relationship System Testing Treatment Protocols Tuberculosis Work Zinc cellular targeting drug development drug discovery enolase genome sequencing interest metalloenzyme mutant new therapeutic target novel novel therapeutics overexpression pathogen prevent resistance mechanism salicylamide screening theories tuberculosis drugs tuberculosis treatment uptake whole genome

项目摘要

Tuberculosis is a major cause of human suffering worldwide, with 1.8 million deaths and 10.4 million new cases in 2015. Although effective drug regimens for the treatment of TB exist, they are lengthy and involve multiple antibiotics to achieve sterilization and prevent relapse. The current treatment for TB is complex and lengthy requiring a minimum of six months with four drugs for the simplest of cases. It is not clear why drug therapy is so prolonged, although several theories relating to the physiological state of the bacteria have been proposed; these include the existence of drug-tolerant populations during infection, the presence of non-replicating (or slowly- replicating bacilli) and the lack of drug penetration to the sites of infection. Much recent effort has been expended in phenotypic screening to identify new molecular series for drug discovery and development; alongside which a chemical genomics approach has been taken to find novel drug targets using hit compounds identified in these screens. We are interested both in developing novel drugs and in understanding how such drugs work. We have identified a common mechanism of resistance to several, chemically-unrelated series in M. tuberculosis which involves mutation in a type VII secretion system (T7SS). We have identified compounds with interesting biological activities and which appear to work via similar mechanisms, or at least resistance is engendered by the same mechanism. Our proposal aims to determine the mode of action of these compounds. We propose that mode of action is via disruption of metal ion homeostasis with additional downstream effects, which would be a novel mechanism for future drug discovery efforts. We have identified mutations in several components of the Esx-3 T7SS (EccA3, EccB3, EccC3 and EccD3) which confer resistance to three compound series. It is unlikely that the Esx-3 system is the cellular target for these compounds, since mutations were found in four different genes, including one cytosolic protein that would not form part of the complex. Therefore it seems likely that resistance arises from a mechanism distinct from loss of compound-target binding. We propose to take a number of approaches combining microbiology, molecular biology and biochemistry to (i) determine the mode of action of compound series (ii) determine how the Esx- 3 T7SS can mediate compound resistance, and (iii) identify and characterize the targets of each series.

结核病是全世界人类痛苦的主要原因，导致 180 万人死亡，10.4 人死亡。 2015 年新增病例数百万。尽管存在治疗结核病的有效药物方案，但它们疗程冗长，涉及多种抗生素以达到绝育和防止复发的目的。这目前的结核病治疗复杂且漫长，需要使用四种药物至少六个月对于最简单的情况。目前尚不清楚为什么药物治疗时间如此之长，尽管有一些已提出有关细菌生理状态的理论；这些包括感染期间耐药群体的存在，非复制（或缓慢复制）的存在复制杆菌）和缺乏药物渗透到感染部位。最近在表型筛选上投入了大量精力来鉴定新的分子系列用于药物发现和开发；与此同时，化学基因组学方法也已利用这些筛选中确定的命中化合物来寻找新的药物靶点。我们有兴趣无论是在开发新药还是在了解这些药物如何发挥作用方面。我们已经确定了一个结核分枝杆菌对几种化学上不相关的系列耐药的共同机制其中涉及 VII 型分泌系统 (T7SS) 的突变。我们已经鉴定出具有有趣生物活性的化合物，并且它们似乎通过类似的机制，或者至少是由相同的机制产生阻力。我们的建议目的是确定这些化合物的作用方式。我们建议行动方式是通过破坏金属离子稳态并产生额外的下游效应，这将是一种新颖的方法未来药物发现工作的机制。我们已鉴定出 Esx-3 T7SS 的多个组件（EccA3、EccB3、EccC3 和 EccD3)，赋予对三种化合物系列的抵抗力。 ESX-3 系统不太可能是这些化合物的细胞靶标，因为在四个不同的基因中发现了突变，包括一种不会形成复合物一部分的胞质蛋白。因此看来有可能耐药性是由一种不同于化合物-靶标结合丧失的机制产生的。我们建议采取多种结合微生物学、分子生物学和生物化学 (i) 确定化合物系列的作用模式 (ii) 确定 Esx- 3 T7SS 可以介导复合耐药性，并且 (iii) 识别和表征每个靶标系列。