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Mechanistic Studies of Gyrase/Topoisomerase IV-Targeted Antibacterials

旋转酶/拓扑异构酶 IV 靶向抗菌药物的机理研究

基本信息

批准号：
10667862
负责人：
NEIL OSHEROFF
金额：
$ 66.89万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-03-23 至 2027-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10667862
关键词：
Acinetobacter baumannii Active Sites Amino Acids Anti-Bacterial Agents Aspartic Acid Bacillus anthracis Bacterial Drug Resistance Binding Bypass Cell Death Cell Death Induction Cells Ciprofloxacin Clinical Complex DNA DNA Damage DNA Double Strand Break DNA Maintenance DNA Topoisomerase IV Double Effect Drug Interactions Drug resistance Drug usage Enzyme Inhibition Enzymes Escherichia coli Fluoroquinolones Francisella tularensis Genetic Materials Genome Goals Handedness Health Human In Vitro Incidence Ions Laboratories Libraries Ligation Mediating Metals Monitor Mutation Mycobacterium tuberculosis Neisseria gonorrhoeae Neurofibrillary Tangles New Agents Oral Pharmaceutical Preparations Phase III Clinical Trials Physiological Positioning Attribute Publishing Research Resistance Role Serine Single-Stranded DNA Site Staphylococcus aureus Structure Superhelical DNA System Topoisomerase II Topoisomerase Inhibitors Toxin Water World Health Organization antimicrobial bacterial resistance cellular targeting clinical efficacy drug action fluoroquinolone resistance in vitro activity in vivo member mutant novel pathogen resistance mechanism targeted agent

项目摘要

Fluoroquinolones, such as ciprofloxacin, are among the most efficacious and broad-spectrum oral antibacterials in clinical use. The World Health Organization lists them in their five “Highest Priority Critically Important Antimicrobials,” and these drugs are the most heavily prescribed antibacterials worldwide. The cellular targets of fluoroquinolones are the bacterial type II topoisomerases, gyrase and topoisomerase IV. These essential enzymes regulate DNA under- and overwinding and remove knots and tangles from the genome by generating transient double-stranded breaks in the genetic material. Fluoroquinolones act by increasing levels of double-stranded DNA breaks generated by gyrase and topoisomerase IV, which converts these enzymes into cellular toxins that fragment the genome. Although gyrase and topoisomerase IV are both physiological targets for fluoroquinolones, their relative importance to drug action appears to be species- and drug-dependent. There is a growing crisis in antibacterial resistance and fluoroquinolone resistance is becoming prevalent. This resistance is threatening the clinical efficacy of fluoroquinolones. Initial fluoroquinolone resistance is most often associated with specific mutations in gyrase and/or topoisomerase IV that occur at a serine residue (originally described as Ser83 in the GyrA subunit of Escherichia coli gyrase) and a glutamic/aspartic acid residue 4 amino acids downstream. Based on a published structure and functional studies from the Osheroff laboratory, these residues are proposed to anchor a water-metal ion bridge that serves as the primary conduit between fluoro- quinolones and gyrase/topoisomerase IV. The identification and characterization of novel agents that act against these well-validated enzyme targets and overcome fluoroquinolone resistance could have important health ramifications. Recently, two new classes of gyrase/topoisomerase IV-targeted agents have been described that appear to overcome this resistance, Novel Bacterial Topoisomerase Inhibitors (NBTIs) and Spiropyrimidinetriones (SPTs). Members of these classes, gepotidacin (NBTI) and zoliflodacin (SPT), have advanced to Phase 3 clinical trials. NBTIs are unique, as they induce single- rather than double-stranded enzyme-generated DNA breaks. However, little is known about the actions of NBTIs and SPTs against gyrase/topoisomerase IV or the mechanism of drug resistance. There is an urgent need to identify drugs that display activity against fluoroquinolone-resistant bacteria. Thus, the goals of this project are to further define the mechanism of action of fluoroquinolones, NBTIs, and SPTs against gyrase and topoisomerase IV in vivo and in cells, to characterize the basis of target-mediated drug resistance, and to identify novel compounds that overcome resistance. Research will benefit from the broad library of wild- type and drug-resistant gyrase/topoisomerase IV available in the Osheroff laboratory, which includes enzymes from Bacillus anthracis, E. coli, Staphylococcus aureus, Mycobacterium tuberculosis, Neisseria gonorrhoeae, Francisella tularensis, and Acinetobacter baumannii. These pathogens have substantial effects on human health.

氟喹诺酮类药物，如环丙沙星，是最有效、最广谱的口服药物之一临床上使用的抗菌药物。世界卫生组织将其列为五个“最重要的优先事项” 重要的抗菌药物”，这些药物是全世界处方最多的抗菌药物。氟喹诺酮类药物的细胞靶点是细菌 II 型拓扑异构酶、旋转酶和 IV 型拓扑异构酶。这些必需的酶可调节 DNA 的缠绕和缠绕，并消除基因组中的结和缠结通过在遗传物质中产生短暂的双链断裂。氟喹诺酮类药物通过增加水平发挥作用由旋转酶和拓扑异构酶 IV 产生的双链 DNA 断裂，将这些酶转化为使基因组片段化的细胞毒素。尽管旋转酶和拓扑异构酶 IV 都是生理靶标对于氟喹诺酮类药物，它们对药物作用的相对重要性似乎取决于物种和药物。抗菌药物耐药性危机日益严重，氟喹诺酮类药物耐药性日益普遍。这耐药性正在威胁氟喹诺酮类药物的临床疗效。最初的氟喹诺酮类药物耐药性最常见与发生在丝氨酸残基处的旋转酶和/或拓扑异构酶 IV 的特定突变相关（最初大肠杆菌促旋酶 GyrA 亚基中的 Ser83）和谷氨酸/天冬氨酸残基 4 个氨基酸下游。基于 Osheroff 实验室发表的结构和功能研究，这些建议残留物锚定水-金属离子桥，作为氟-金属离子之间的主要管道。喹诺酮类和旋转酶/拓扑异构酶 IV。针对这些经过充分验证的酶靶标的新型药物的鉴定和表征克服氟喹诺酮耐药性可能会对健康产生重要影响。最近新开两个班旋转酶/拓扑异构酶 IV 靶向药物已被描述，似乎可以克服这种耐药性，新颖细菌拓扑异构酶抑制剂 (NBTI) 和螺嘧啶三酮 (SPT)。这些班级的成员， gepotidacin（NBTI）和zoliflodacin（SPT）已进入3期临床试验。 NBTI 是独一无二的，因为它们诱导单链而不是双链酶产生的 DNA 断裂。然而，人们对此知之甚少 NBTIs 和 SPTs 对旋转酶/拓扑异构酶 IV 的作用或耐药机制。迫切需要鉴定对氟喹诺酮耐药细菌具有活性的药物。因此，该项目的目标是进一步明确氟喹诺酮类药物、NBTI 和 SPT 的作用机制体内和细胞中的旋转酶和拓扑异构酶 IV，以表征靶标介导的耐药性的基础，并鉴定克服耐药性的新化合物。研究将受益于广泛的野生图书馆 Osheroff 实验室提供类型和耐药性旋转酶/拓扑异构酶 IV，其中包括酶来自炭疽杆菌、大肠杆菌、金黄色葡萄球菌、结核分枝杆菌、淋病奈瑟菌、土拉弗朗西斯菌和鲍曼不动杆菌。这些病原体对人类健康具有重大影响。