N-Thiolated Beta-Lactams

N-硫醇化β-内酰胺

基本信息

批准号：
6622863
负责人：
EDWARD TUROS
金额：
$ 32.63万
依托单位：
UNIVERSITY OF SOUTH FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-03-01 至 2007-02-28
项目状态：
已结题

项目摘要

This project focuses on a very challenging problem in the medical community, the development of treatments for drug- resistant bacterial infections. The leading cause of clinical complications in the United States is nocosomial infections caused by the drug-resistant pathogen, Staphylococcus aureus. There is currently a dire need for new drugs to be developed for controlling these infections. Towards this goal, our proposal discusses efforts to identify the biochemical and chemical basis for antibacterial activity of N-thiolated beta-lactams, a new class of antibiotics discovered in our laboratory at University of South Florida. Preliminary data on more than 50 active analogues indicates that these substances possess antimicrobial behavior selective for Staphylococcus bacteria, with enhanced activity towards multi-drug resistant strains (MRSA). Unlike all previously known beta-lactam drugs, these compounds appear to affect early developmental events during cell replication, not cell wall crosslinking. These compounds have highly unusual structure-activity profiles which need to be explored further. Electron microscopy experiments indicate that our lactams produce no morphological defects in MRSA cells, or cytotoxic effects in human fibroblasts. The compounds are stable over a wide pH range (pH 1 to 10), and are totally transparent to penicillinases as well as to most chemical reagents we have studied. Our Proposed Studies consist of three Specific Aims. Aim 1 is to study the biochemical and chemical basis for antimicrobial activity, and will include (1) electron microscopy experiments to look for morphological defects in bacterial cells due to damage by the lactams, and to identify where the drug accumulates in the cell, (2) radiolabeling to determine which of the primary cellular processes (cell wall synthesis, protein synthesis, or nucleic acid synthesis) are affected by the beta-lactams, and the means by which the drugs function chemically, and (3) studies to define whether the lactams bind covalently or non-covalently to the biological target, and to identify the cellular target. Aim 2 is to assess further whether the lactams are cytotoxic to mammalian cells. Aim 3 is to develop new approaches to solid phase synthesis of affinity resins (for experiments on isolating the cellular target) and lactam libraries (for expanded drug screening). We also aim to develop novel prodrug delivery systems for the prevention and treatment of MRSA infections. We believe that these studies will provide extraordinary opportunities to develop new therapeutics and approaches for the control of hospital-borne drug-resistant infections.

该项目着重于医学界一个非常具有挑战性的问题，即耐药细菌感染的治疗方法。美国临床并发症的主要原因是由耐药性病原体葡萄球菌金黄色葡萄球菌引起的致病性感染。目前，需要开发用于控制这些感染的新药。为了实现这一目标，我们的提案讨论了确定N-硫醇化β-内酰胺的抗菌活性的生化和化学基础的努力，这是一种在南佛罗里达大学实验室中发现的一种新的抗生素。关于50多种活性类似物的初步数据表明，这些物质对葡萄球菌具有选择性的抗菌行为，具有增强对多药抗性菌株的活性（MRSA）。与所有以前已知的β-内酰胺药物不同，这些化合物似乎会影响细胞复制过程中的早期发育事件，而不是细胞壁交联。这些化合物具有高度不寻常的结构活性曲线，需要进一步探索。电子显微镜实验表明，我们的lactam在MRSA细胞中没有形态缺陷，或者在人成纤维细胞中没有细胞毒性作用。这些化合物在宽的pH范围内是稳定的（pH 1至10），并且完全透明了青霉素酶以及我们研究过的大多数化学试剂。我们提出的研究包括三个具体目标。目的1是研究抗菌活性的生化和化学基础，并包括（1）电子显微镜实验，以查找由于乳酸氨酰胺的损害而导致细菌细胞中的形态缺陷，并确定药物在细胞中积累的位置，（2）biqualion cyleseiss of Provice of Cellular Provessiss，蛋白质合成，蛋白质合成，蛋白质合成，蛋白质合成，蛋白质合成构成合成蛋白质合成，构成了构成合成构成的合成蛋白质合成，构成了核酸含量。 β-内酰胺和药物在化学上发挥作用的手段，以及（3）研究乳酰胺的定义是共价还是非共价与生物学靶标结合并鉴定细胞靶标。目标2是进一步评估乳糖是否对哺乳动物细胞具有细胞毒性。 AIM 3是开发新方法来合成亲和力树脂（用于隔离细胞靶标的实验）和乳糖果库（用于扩展的药物筛查）。我们还旨在开发用于预防和治疗MRSA感染的新型前药输送系统。我们认为，这些研究将为开发新的治疗剂和方法来控制医院耐药的耐药性感染。