Polymer conjugates that adapt vancomycin to overcome resistance in Gram-negative bacteria

非技术摘要耐药细菌的迅速传播是一个严重的全球健康危机。在过去的40年里，没有新的抗生素来治疗耐药细菌感染。创建新的抗生素疗法的一个问题是革兰氏阴性细菌（如大肠杆菌）的不可渗透的外膜（OM），其阻止某些抗生素的进入。例如，万古霉素是一种有前途的抗生素的最后手段，但由于它不能穿透细菌的OM，它是不成功的革兰氏阴性细菌感染。本研究的长期目标是开发一种新的方法，将万古霉素转化为耐药革兰氏阴性菌感染的有效治疗方法。这项研究的信息将帮助研究人员制定新的规则来设计一种载体，帮助有效的药物绕过OM并到达细菌内的靶点。该研究增加了可用于治疗耐药细菌感染的抗生素数量，并显着改善患者的健康状况。拟议的研究是跨学科的。学生和博士后将学习分子设计，如何建立聚合物-抗生素对，并进行涉及聚合物化学，生物材料和微生物学的研究项目。为了促进多样性，公平性和包容性，PI接受密歇根大学本科生研究机会计划的学生。PI通过ACS POLY/PMSE学生分会外展计划与小学和中学接触。PI参加了UM的夏季研究机会计划，作为来自全国各地的代表性不足的学生的研究导师。PI还将与日本的研究团体建立国际研究合作和学生交流计划。将仅革兰氏阳性的万古霉素转化为对革兰氏阴性菌有活性的万古霉素是一种有前途的方法，以增加我们对耐药菌的新抗生素库。然而，对于大/球状糖肽万古霉素，尚未建立转化的分子规则。为此，膜活性聚合物载体将被设计为穿过外膜（OM），增加内（细胞质）膜（IM）上万古霉素的局部浓度，并将万古霉素递送至细胞分裂隔膜区域，在该区域万古霉素将最具活性。本研究的具体目标是了解聚合物-药物偶联物的结构-活性-机制关系，并确定其临床应用的治疗潜力。为了实现这些目标，将通过点击化学合成万古霉素与阳离子两亲性共聚物的共价缀合物。将研究抗微生物活性和潜在作用机制，以确定结合物渗透OM、在IM上浓缩万古霉素以及在隔膜处蓄积的能力。为了评价偶联物的治疗潜力，PI将评价偶联物对哺乳动物细胞的细胞毒性、对碳青霉烯类耐药大肠埃希菌的效力。大肠杆菌，和对其他革兰氏阴性细菌病原体的活性谱。预期的结果将为聚合物载体的分子设计提供合理且可预测的指导方针，用于将药物靶向递送到细菌内的特定膜结构。这项研究的成果也将增加我们对聚合物和细菌细胞结构之间的物理化学相互作用的理解，这可以用来提高抗生素的抗菌活性。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-technical abstractThe rapid spread of drug-resistant bacteria is a severe global health crisis. In the last 40 years, there has not been new antibiotics to treat drug-resistant bacterial infections. One issue for creating a new antibiotic therapy is the impermeable outer membrane (OM) of Gram-negative bacteria such as Escherichia coli, which prevents entry of certain antibiotics. For example, vancomycin is a promising antibiotic of last resort, but since it cannot penetrate the bacteria’s OM, it is not successful for Gram-negative bacterial infections. The long-term goal of this study is to develop a new way to convert vancomycin into an effective treatment of drug-resistant Gram-negative bacterial infections. The information from this study will help researchers create new rules to design a carrier that helps effective drugs bypass the OM and reach the target sites within bacteria. The study increases the number of antibiotics available to treat drug-resistant bacterial infections and significantly improve a patient’s health. The proposed research is interdisciplinary. Students and postdocs will learn molecular design, how to build polymer-antibiotic pairs, and conduct research projects involving polymer chemistry, biomaterials, and microbiology. To contribute to diversity, equity, and inclusion, the PI accepts students from the University of Michigan’s Undergraduate Research Opportunity Program. The PI engages primary and secondary schools through the ACS POLY/PMSE student chapter outreach program. The PI participates in the UM’s Summer Research Opportunity Program as a research mentor for under-represented students from across the country. The PI will also build international research collaborations and student exchange programs with research groups in Japan. Technical abstractConverting Gram-positive-only vancomycin to be active against Gram-negative bacteria is a promising approach to increase our arsenal of new antibiotics against drug-resistant bacteria. However, molecular rules for the conversion have not been established for the large/globular glycopeptide vancomycin. To that end, membrane-active polymer carriers will be designed to pass through the outer membrane (OM), increase the local concentration of vancomycin on the inner (cytoplasmic) membrane (IM), and deliver vancomycin to the cell division septum region, where vancomycin would be most active. The specific goals of this study are to understand the structure-activity-mechanism relationship of the polymer-drug conjugates and determine their therapeutic potential for clinical applications. To achieve these goals, covalent conjugates of vancomycin with the cationic amphiphilic copolymers will be synthesized through click chemistry. The antimicrobial activity and underlying mechanism of action will be studied to determine the abilities of conjugates to permeate the OM, concentrate vancomycin on the IM, and accumulate at the septum. To evaluate the therapeutic potential of conjugates, the PI will evaluate the cytotoxicity of conjugates to mammalian cells, potency against carbapenem-resistant E. coli, and the spectrum of activity against other Gram-negative bacterial pathogens. The expected outcomes will lead to a rational and predictable guideline for molecular design of polymer carriers for targeted drug delivery to the specific membrane structure within bacteria. The outcomes of this research will also increase our understating of the physicochemical interactions between polymer and bacterial cell structures, which can be exploited to enhance the antimicrobial activity of antibiotics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.