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

• 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
• 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

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，是最有效和广谱的口服药物之一。 临床应用中的抗菌药物。世界卫生组织将它们列为五大最优先事项 重要的抗菌药，“这些药物是全世界处方最多的抗菌药。 氟喹诺酮类药物的细胞靶点是细菌的II型拓扑异构酶、旋转酶和拓扑异构酶IV。 这些必需的酶调节dna的过低和过卷，并从基因组中去除打结和缠结。 通过在遗传物质中产生瞬间的双链断裂。氟喹诺酮类药物的作用水平 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 使基因组碎裂的细胞毒素。虽然旋转酶和拓扑异构酶IV都是生理靶点 对于氟喹诺酮类药物，它们对药物作用的相对重要性似乎与物种和药物有关。 细菌耐药性危机日益严重，对氟喹诺酮类药物的耐药性正在变得普遍。这 耐药性正在威胁着氟喹诺酮类药物的临床疗效。最初的氟喹诺酮耐药最常见的是 与发生在丝氨酸残基上的旋转酶和/或拓扑异构酶IV的特定突变有关(最初 描述为大肠杆菌旋转酶gyrA亚基中的Ser83)和谷氨酸/天冬氨酸残基4个氨基酸 顺流而下的酸。基于Osheroff实验室发表的结构和功能研究，这些 残基被认为是锚定水-金属离子桥的，该桥是氟和氟之间的主要通道。 喹诺酮类和旋转酶/拓扑异构酶IV。 针对这些有效的酶靶标的新型药物的鉴定和特性 克服氟喹诺酮耐药性可能会对健康产生重要影响。最近，两个新班级 已经描述了似乎可以克服这种耐药性的旋转酶/拓扑异构酶IV靶向药物，新颖 细菌拓扑异构酶抑制剂(NBTIs)和螺嘧啶三酮类(SPTS)。这些班级的成员， 吉泊达星(NBTI)和佐利洛星(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的酶产生的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。 迫切需要找出对氟喹诺酮耐药细菌有活性的药物。因此， 该项目的目标是进一步确定氟喹诺酮类药物、NBTIs和SPTS对 体内和细胞内的旋转酶和拓扑异构酶IV，以表征靶向介导的耐药性的基础， 并确定克服抗药性的新化合物。研究将受益于广泛的野生生物图书馆- Osheroff实验室提供的类型和抗药性旋转酶/拓扑异构酶IV，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、淋球菌、 和鲍曼不动杆菌。这些病原体对人类健康有重大影响。