Interruption of Signaling-Mediated Bacterial Persistent Infections

中断信号介导的细菌持续感染

基本信息

批准号：
9033070
负责人：
LAURENCE G RAHME
金额：
$ 78.04万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-03-01 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9033070
关键词：
Acinetobacter baumannii Adopted Animal Model Antibiotic Resistance Antibiotic Therapy Antibiotics Bacteria Bacterial Infections Benzamides Biochemical Biological Assay Burkholderia Cell Communication Cells Chemicals Chronic Clinical Clinical Research Coupling DNA Data Development Drug Combinations Drug Kinetics Drug resistance Effectiveness Evaluation Exposure to Figs - dietary Future Gene Expression Alteration Generations Goals Gram-Negative Bacteria Health Host Defense Human In Vitro Infection Inflammatory Interruption Intervention Klebsiella pneumonia bacterium Lead Left Mediating Metabolism Microbial Biofilms Molecular Weight Mono-S Multi-Drug Resistance Pharmaceutical Preparations Phase Population Population Density Prevention Property Pseudomonas aeruginosa Publishing Refractory Relapse Resistance Ribosomes Series Signal Transduction Signaling Molecule Structure-Activity Relationship Testing Toxicology Translations Type I DNA Topoisomerases Virulence absorption antimicrobial bactericide benzimidazole analog improved in vivo inhibitor/antagonist killings mouse model mutant novel novel therapeutics pathogen preclinical study prevent quorum sensing research study response small molecule

项目摘要

DESCRIPTION (provided by applicant): Persistent and chronic infections are often refractory to antibiotics due to antibiotic tolerance of a subpopulation of cells that are not antibiotic resistant mutants, but rather are "dormant" cells that survive antibiotic killing. Our findings show that Pseudomonas aeruginosa and Burkholderia species excrete a small molecule that serves as a persistence "infochemical" that signals the accumulation of these antibiotic tolerant persister (AT/P) cells and changes that are critical for pathogen adaptation and important for chronic infection. Our aim is to achieve a paradigm shift in persistent infection interventions by introducing a treatment that disrupts the bacterial signaling that induces AT/P cell formation using compounds we have identified; to achieve this aim we will refine and validate lead compounds in vivo, using adapted mouse models of infection. Our approach is fundamentally different from traditional antimicrobial therapies as it specifically targets the AT/P subpopulation of cells that survive antibiotic treatment (and host defense killing mechanisms), and that are ultimately responsible for persistent and relapsing infections. We propose to develop this approach through experiments employing P. aeruginosa, a recalcitrant Gram-negative bacterium that defies eradication by antibiotics, forms biofilms, and exemplifies current clinical problematic pathogens. In the R21 phase Aim 1 studies, we will use structure-activity relationship (SAR) data to refine the chemical compositions of the particularly promising 1st generation compounds we have identified. The feasibility of this approach has been established by our prior generation of a series of structurally related agents that block the synthesis of a pr-AT/P signaling molecule and reduce virulence in vivo. In Aim 2, we will perform a series of microbiological, cellular, and biochemical evaluations of the 2nd generation compounds to assess their relative IC50 values and their efficacy against several clinical isolates (including pan-resistant and multi-drug resistant isolates) when used in combination with different classes of antibiotics or alone, as well as their ability to disrupt the synthesis of the signaling molecule and prevent the resultant imbalance in DNA topology and translational effects that we have demonstrated to occur in cells that have transitioned to the AT/P state. The R33 phase (Aims 3 and 4) will be undertaken if our well-defined milestones are achieved. In Aim 3, we will assess the pharmacological efficiency properties of the most promising 2nd generation compounds identified in the R21 phase. In Aim 4, the compounds' efficacies against drug resistant, tolerant pathogens that co-exist with P. aeruginosa in human infections and similarly form AT/P cells (i.e. Acinetobacter baumannii, Klebsiella pneumoniae, and Burkholderia species) will be tested in mono- and polymicrobial planktonic and biofilm settings. Combination drug assays will be performed to determine whether our lead molecules improve antibiotic clearance of biofilms. Highly prioritized advanced leads will then be validated in established mouse models that we have developed. The overall goal of these studies is to carefully assess the potential utility of lead small molecules that target AT/P cells as a new way to intervene against chronic and persistent infections that have thus far been untreatable. These anti-AT/P molecules may be combined with traditional antibiotic therapies for optimal effectiveness.

描述（由申请人提供）：持续性和慢性感染通常对抗生素耐药，因为细胞亚群具有抗生素耐受性，这些细胞亚群不是抗生素抗性突变体，而是在抗生素杀死后存活下来的“休眠”细胞。我们的研究结果表明，铜绿假单胞菌和伯克霍尔德氏菌会分泌一种小分子，作为持久性“信息化学物质”，向这些抗生素耐受性持久细胞（AT/P）的积累发出信号，并发出对病原体适应至关重要的变化，对慢性感染也很重要。我们的目标是通过引入一种治疗方法来实现持续性感染干预的范式转变，该治疗方法使用我们已鉴定的化合物来破坏诱导 AT/P 细胞形成的细菌信号传导；为了实现这一目标，我们将使用适应的小鼠感染模型在体内完善和验证先导化合物。我们的方法与传统的抗菌疗法有根本的不同，因为它专门针对在抗生素治疗（和宿主防御杀伤机制）中存活下来的 AT/P 细胞亚群，并且最终导致持续性和复发性感染。我们建议通过使用铜绿假单胞菌的实验来开发这种方法，铜绿假单胞菌是一种顽固的革兰氏阴性细菌，无法用抗生素根除，形成生物膜，并成为当前临床问题病原体的例证。在 R21 阶段目标 1 研究中，我们将使用构效关系 (SAR) 数据来完善我们已确定的特别有前途的第一代化合物的化学成分。我们上一代的一系列结构相关的试剂已证实了这种方法的可行性，这些试剂可阻断 pr-AT/P 信号分子的合成并降低体内毒力。在目标 2 中，我们将对第二代化合物进行一系列微生物学、细胞和生化评估，以评估其相对 IC50 值及其在用于多种临床分离株（包括泛耐药和多重耐药分离株）时的功效。与不同类别的抗生素组合或单独使用，以及它们破坏信号分子合成并防止由此产生的 DNA 拓扑结构失衡和翻译效应的能力，我们已证明这种失衡发生在已转变为 AT/P 的细胞中状态。如果我们明确的里程碑得以实现，则将进入 R33 阶段（目标 3 和 4）。在目标 3 中，我们将评估 R21 阶段确定的最有前途的第二代化合物的药理效率特性。在目标 4 中，这些化合物对人类感染中与铜绿假单胞菌共存且类似形成 AT/P 细胞的耐药、耐受病原体（即鲍曼不动杆菌、肺炎克雷伯菌和伯克霍尔德杆菌）的功效将在单细胞试验中进行测试。以及多种微生物浮游和生物膜环境。将进行组合药物测定，以确定我们的先导分子是否可以改善生物膜的抗生素清除率。然后，高度优先的高级线索将在我们开发的已建立的小鼠模型中得到验证。这些研究的总体目标是仔细评估针对 AT/P 细胞的先导小分子的潜在效用，作为干预迄今为止无法治疗的慢性和持续性感染的新方法。这些抗 AT/P 分子可以与传统抗生素疗法结合以获得最佳效果。