Chemical Methods for Ferrous Iron Dependent Drug Delivery

摘要 多重耐药革兰氏阴性病原体（特别是铜绿假单胞菌， 肺炎克雷伯菌、鲍曼不动杆菌和肠杆菌科）代表最严重的 当今传染病临床医生面临的挑战。这种情况突出表明，迫切需要新的 治疗和创新的新的治疗方法，以成功地治疗这些感染。 在这个R01项目的初期，我们开发了一种新的小分子方法，用于Fe2+依赖的 递送不同的药物（或报告基因）有效载荷。该平台现已在细胞和小鼠中得到很好的验证 疟疾和癌症的模型。在项目的下一阶段，我们将应用并优化这一策略， 靶向重要革兰氏阴性"ESKAPE"病原体。我们的假设是宿主和病原体之间的相互作用 铁资源竞争的结果提供了多种机会，以Fe2+为目标进行干预 抗生素铜绿假单胞菌单独采用的各种铁获取策略预测了靶向铁的摄取。 取决于疾病，细胞外、周质和细胞质隔室中的不稳定Fe 2+池 感染的状态和部位。 我们的研究计划要求合成Fe2+靶向抗生素缀合物，其设计用于被动（目的1）或 主动（通过铁载体介导的摄取;目的2），通过GM阴性膜，和释放室- 在与Fe 2+反应后，适当的抗生素有效载荷。研究和核实其运输方式， 激活后，我们将采用非Fe 2+反应性对照缀合物，以及一组精心选择的野生型和 具有改变的渗透性、外排泵/孔蛋白表达或铁载体/转运蛋白表达的突变菌株。 将在铁缺乏和铁充足条件下使用疾病- 相关的、环境特异性的铁源，以模拟周围宿主-病原体相互作用的微环境。 铁.将针对获得的一组GM阴性临床分离株评价最有效的结合物 不同的感染部位和疾病状态。这些研究将为铁的获取提供新的见解 途径的GM阴性细菌，并将告知有前途的线索，为进一步研究在小鼠的选择 感染模型最后，为了利用铜绿假单胞菌生物膜形成过程中产生的胞外Fe 2+，我们 将合成和表征第一个Fe2+敏感的“智能”材料（目标3）。用作涂料， 这些新型材料可以原位检测生物膜的形成，并准确地递送抗生素。 在需要的地方和时间。总之，本项目将应用见解和化学策略 在最初的R01期间发展到一个新的治疗领域，目的是引入几个新的 抗菌治疗领域的创新。

Abstract The emergence of multi-drug resistant Gram-negative pathogens (especially Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and the Enterobacteriaceae) represents the most serious challenge faced by infectious disease clinicians today. This situation highlights the urgent need for new therapeutics and innovative new therapeutic approaches to successfully treat these infections. In the initial period of this R01 project, we developed a novel small-molecule approach for the Fe2+-dependent delivery of diverse drug (or reporter) payloads. This platform has now been well validated in cells and in mouse models of malaria and cancer. In the next period of the project, we will apply and optimize this strategy to target important Gm-negative “ESKAPE” pathogens. Our hypothesis is that host-pathogen interactions resulting from competition for iron resources present multiple opportunities for intervention with Fe2+-targeted antibiotics. The various iron acquisition strategies employed by P. aeruginosa alone predict for targetable pools of labile Fe2+ in the extracellular, periplasmic, and cytoplasmic compartments, depending on disease state and site of infection. Our research plan calls for the synthesis of Fe2+-targeted antibiotic conjugates designed to passively (Aim 1) or actively (via siderophore-mediated uptake; Aim 2), transit Gm-negative membranes, and release compartment- appropriate antibiotic payloads following reaction with Fe2+. To study and verify their modes of transport and activation, we will employ non-Fe2+ reactive control conjugates, and a carefully selected panel of wild-type and mutant strains with altered permeability, efflux pump/porin expression, or siderophore/transporter expression. Susceptibility (MIC) testing will be performed under iron depleted and iron replete conditions using disease- relevant, context specific, iron sources to mimic the microenvironment of the host-pathogen interaction around iron. The most effective conjugates will be evaluated against a panel of Gm-negative clinical isolates obtained from diverse infection sites and disease states. These studies will provide new insights into the iron acquisition pathways of Gm-negative bacteria, and will inform the selection of promising leads for further study in murine infection models. Finally, to exploit the extracellular Fe2+ produced during P. aeruginosa biofilm formation, we will synthesize and characterize the first Fe2+-sensitive “smart” materials (Aim 3). Used as coatings on indwelling devices, these novel materials would detect biofilm formation in situ and deliver antibiotics exactly where and when they are needed. In summary, this project will apply the insights and chemical strategies developed during the initial R01 period to a new therapeutic area, with the aim of introducing several new innovations to the field of antibacterial therapy.