Stimuli-Responsive Polymer-Drug Conjugates: A New Strategy to Fight Antimicrobial Resistance

项目摘要 由于抗生素耐药性（AMR）的增加，传染病对公共卫生的威胁日益严重， 新抗生素开发停滞。如果不加以控制，每年可归因于AMR的死亡人数为 估计到2050年将达到1000万人，超过癌症和糖尿病造成的死亡人数。因此，迫切需要 我们需要制定创新办法来应对这一严重的全球危机。 我们的目标是开发创新的、高效的、生物相容的pH或ROS响应性抗菌聚合物， 药物（即，抗生素）缀合物（PDCs），可以有效治疗严重的感染性疾病， AMR，同时确保高生物相容性。我们将利用现有的FDA批准的抗生素来实现这一目标， 疾病特异性刺激，和一个独特的工程生物相容性阳离子聚合物。阳离子聚合物可以是 有效的抗生素载体，因为它们可以在细菌壁/膜上诱导孔，从而显著增强 将抗生素转运到细菌中，并使它们绕过细菌中的外排泵， 膜的阳离子PDCs也可以（1）粘附在细菌表面，从而作为药物储存库， 局部释放药物，和（2）有效地渗透细菌生物膜，从而导致更深的抗生素渗透。 阳离子聚合物和抗生素之间的强协同效应降低了微生物的固有抗性。 病原体，从而导致显著增强的抗微生物功效，特别是对于AMR病原体。 抗生素将通过pH或ROS响应性接头缀合到阳离子聚合物上，作为炎性聚合物。 感染组织中的微环境具有低pH水平和高水平的活性氧（ROS）。 此外，我们设计了一种GSH可裂解和电荷反转的阳离子聚合物，可以大大降低其 全身毒性以及哺乳动物细胞的细胞毒性。最后，PDC能够刺激（疾病特异性）- 由于渗透增强，药物控释可优先在感染组织处累积 和保留（EPR）作用，从而进一步降低全身毒性，同时实现高抗微生物功效。 在目标1中，我们将设计，合成和表征pH和ROS响应的PDCs。我们将首先调查 许多游离的（即，结合前）FDA批准的抗生素和我们独特的 设计的刺激响应和电荷反转生物相容性阳离子聚合物。在目标2中，抗微生物剂和 薄膜功效、耐药性发展概况和所得刺激物的生物相容性- 将在多种细菌物种中评价响应性PDC。在目标3中，我们将系统地确定 最大耐受剂量、体内生物分布、抗微生物功效和潜在全身毒性 在三种临床相关的细菌感染小鼠模型中选择PDC。 这项研究将创建一个新的类PDCs的基础上，我们设计的独特的生物相容性阳离子聚合物， 各种FDA批准的抗生素，以及一些刺激响应连接体，可以有效地对抗 普遍存在的耐药性危机，并提供一种通用、有效且安全的解决方案来治疗多种类型的感染。

PROJECT SUMMARY Infectious diseases are a growing threat to public health owing to increasing antimicrobial resistance (AMR) and stagnation in new antibiotic development. Left unchecked, the annual number of deaths attributable to AMR is estimated to reach 10 million by 2050, exceeding deaths due to cancers and diabetes. Thus, there is an urgent need to develop innovative approaches to tackle this serious global crisis. We aim to develop innovative, highly efficient, and biocompatible pH- or ROS-responsive antimicrobial polymer- drug (i.e., antibiotics) conjugates (PDCs), which can effectively treat serious infectious diseases and overcome AMR while ensuring high biocompatibility. We will accomplish this goal utilizing existing FDA-approved antibiotics, disease-specific stimuli, and a uniquely engineered biocompatible cationic polymer. Cationic polymers can be effective antibiotic carriers as they can induce pores on the bacterial wall/membrane, thus significantly enhancing the transport of antibiotics into the bacteria and allowing them to bypass the efflux pump in the bacterial membrane. Cationic PDCs can also (1) stick to the bacteria’s surface, thereby serving as a drug reservoir to release drug locally, and (2) effectively infiltrate bacterial biofilms, thereby leading to deeper antibiotic penetration. The strong synergistic effects between cationic polymers and antibiotics diminish the intrinsic resistance of the pathogens, thus leading to significantly enhanced antimicrobial efficacy, especially for AMR pathogens. Antibiotics will be conjugated onto the cationic polymer via pH- or ROS-responsive linkers as the inflammatory microenvironment in infected tissues have low pH levels and high levels of reactive oxygen species (ROS). Furthermore, we engineered a GSH-cleavable and charge-reversal cationic polymer that can greatly reduce its systemic toxicity as well as cellular toxicity for mammalian cells. Lastly, PDC capable of stimuli (disease-specific)- controlled drug release can accumulate preferentially at the infected tissues due to the enhanced permeation and retention (EPR) effect, thereby further reducing systemic toxicity while achieving high antimicrobial efficacy. In Aim 1, we will design, synthesize and characterize pH- and ROS-responsive PDCs. We will first investigate the synergy between a number of free (i.e., before conjugation) FDA-approved antibiotics and our uniquely designed stimuli-responsive and charge-reversal biocompatible cationic polymer. In Aim 2, the antimicrobial and antibiofilm efficacies, drug resistance development profiles, and biocompatibilities of the resulting stimuli- responsive PDCs will be evaluated in multiple bacteria species. In Aim 3, we will systematically determine the maximum tolerated dose, in vivo biodistribution, antimicrobial efficacy, and potential systemic toxicity of the selected PDCs in three clinically relevant bacterial infection mouse models. This study will create a new class of PDCs based on the unique biocompatible cationic polymer we engineered, various FDA-approved antibiotics, and a number of stimuli-responsive linkers, which can effectively combat the prevalent AMR crisis and offer a general, yet effective and safe, solution to treat many types of infections.