Dual-Stimuli Responsive Antibiotic-Loaded Nanoparticles: A New Strategy to Overcome 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。我们的目标是开发一个新的类 双刺激响应性多糖包被的纳米颗粒（NP），其能够包封宽范围的 FDA批准的抗生素可有效治疗多重耐药（MDR）细菌感染。多糖 NP壳保证了良好的稳定性和较长的血液循环时间，从而导致NP在体内的高积累 通过增强的渗透和保留效果，感染的组织。此外，多糖使NP 由于对细菌凝集素的多价亲和性而物理结合病原体。独特设计的NP是 在炎症微环境中被高水平的ROS和/或低pH激活， 抗微生物聚合物和抗生素，显示出强大的协同作用，以打击MDR病原体。阳离子 聚合物可以在细菌细胞膜上诱导孔，并显著降低细菌细胞膜的固有阻力。 通过增强抗生素进入细菌的运输，并允许它们绕过外排， 泵感染组织中释放的阳离子聚合物也可以聚集病原体并形成一个 这意味着微环境捕获高水平的抗微生物材料，从而导致高的抗微生物功效。 此外，NP可以穿透细菌生物膜，并增强巨噬细胞对抗生素的摄取。 从而有效地分别消除众所周知的具有挑战性的生物膜和细胞内感染。 最后，阳离子聚合物在其主链中含有GSH-可裂解键，其可容易地在聚合物中降解。 哺乳动物细胞的胞质溶胶，从而避免了与其他阳离子的剂量限制毒性的问题 聚合物在我们成功的试点研究之后，我们将系统地优化和表征定制的NP 来治疗四种不同的MDR病原体在目标1中，我们将确定最佳的多糖NP壳，抗生素， 和用于四种MDR病原体的每一种的NP制剂。在目标2中，我们将研究候选纳米粒子的抗菌性 和生物相容性，以获得一个基本的 理解针对感兴趣的病原体的有效和安全的抗微生物NP的设计规则。在Aim中 3、我们将确定最大耐受剂量、全身毒性、免疫学后果、体内 生物分布，药代动力学，和抗微生物功效的选择纳米粒子在健康小鼠和三个 临床相关的动物感染模型。总之，这项研究将导致一类新的抗菌纳米颗粒 基于疾病特异性刺激，一种独特的双刺激响应和生物相容性阳离子聚合物， 工程，多糖靶向MDR病原体，和FDA批准的抗生素。如果成功，它将提供 一种通用、有效且安全的解决方案，可有效消除最常见的MDR病原体。

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 a new class of dual-stimuli responsive polysaccharide-coated nanoparticles (NP) capable of encapsulating a wide range of FDA-approved antibiotics to effectively treat multidrug-resistant (MDR) bacterial infections. The polysaccharide NP shell ensures good stability and long blood circulation time, thus leading to high NP accumulation in the infected tissues via the enhanced permeation and retention effect. Furthermore, polysaccharides enable the NP to physically bind the pathogens due to multivalent affinity for bacterial lectins. The uniquely engineered NP is activated by high levels of ROS and/or low pH in the inflammatory microenvironment to release both cationic antimicrobial polymers and antibiotics that show a strong synergy to combat MDR pathogens. The cationic polymers can induce pores on the bacterial cell membrane, and significantly diminish the intrinsic resistance of the pathogens by enhancing the transport of antibiotics into the bacteria and allowing them to bypass the efflux pump. The cationic polymers released in the infected tissues can also agglomerate the pathogens and shape a microenvironment entrapping a high level of antimicrobial materials, thus leading to high antimicrobial efficacy. Moreover, the NP can penetrate through bacterial biofilms, and enhance the uptake of antibiotics by macro- phages, thereby effectively eliminating notoriously challenging biofilm and intracellular infections, respectively. Finally, the cationic polymer contains GSH-cleavable bonds in its main chain, which can be readily degraded in the cytosol of mammalian cells, thereby sidestepping the problem of dose-limiting toxicity with other cationic polymers. Following on our successful pilot studies, we will systematically optimize and characterize NPs tailored to treat four different MDR pathogens. In Aim 1, we will determine the optimal polysaccharide NP shell, antibiotics, and NP formulation for each of the four MDR pathogens. In Aim 2, we will study the candidate NPs’ antimicrobial and antibiofilm efficacy, drug resistance development profile, and biocompatibility to gain a fundamental understanding of the design rules for efficacious and safe antimicrobial NP against pathogens of interest. In Aim 3, we will determine the maximum tolerated dose, systemic toxicity, immunological consequences, in vivo biodistribution, pharmacokinetics, and antimicrobial efficacy of the selected NPs in healthy mice and three clinically relevant animal infection models. Altogether, this study will lead to a new class of antimicrobial NPs based on disease-specific stimuli, a unique dual-stimuli responsive and biocompatible cationic polymer we engineered, polysaccharides targeting MDR pathogens, and FDA-approved antibiotics. If successful, it will offer a general, yet effective and safe solution to effectively eliminate the most prevalent MDR pathogens.