Lethal action of fluoroquinolones with non-growing Mycobacterium tuberculosis

氟喹诺酮类药物对非生长结核分枝杆菌的致死作用

• 批准号: 8062289
• 负责人: KARL A DRLICA
• 金额: $ 71.82万
• 依托单位: UNIV OF MED/DENT OF NJ-NJ MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-15 至 2012-08-20
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8062289
• 关键词: Address; Aerobic; Affect; Amino Acids; Animal Model; Antitubercular Agents; Bacteria; Binding; Biochemical; Biological Assay; Cell Culture Techniques; Cell Death; Cell-Free System; Cells; Cessation of life; Chemicals; Chloramphenicol; Chromosomes; Chronic; Colony-forming units; Complex; Cultured Cells; DNA; DNA Gyrase; DNA biosynthesis; Data; Dose; Drops; Edetic Acid; Endopeptidase K; Enzymes; Escherichia coli; Excision; Feedback; Fluoroquinolones; Generations; Genus Mycobacterium; Goals; Growth; Homologous Gene; In Vitro; Incubated; Infection; Iowa; Knowledge; Lead; Life; Link; Liquid substance; Lung; Mass Spectrum Analysis; Measurement; Measures; Mediating; Methods; Modeling; Molecular Target; Moxifloxacin; Multidrug-Resistant Tuberculosis; Mus; Mutation; Mycobacterium tuberculosis; Nalidixic Acid; Nitric Oxide; Norfloxacin; Oxygen; Pharmaceutical Preparations; Plasmids; Positioning Attribute; Predisposition; Procedures; Property; Protein Biosynthesis; Protein Synthesis Inhibition; Proteins; Quinolones; Reaction; Research; Resistance; Route; Sedimentation process; Site; Solutions; Structure; System; Testing; Therapeutic; Time; Tuberculosis; Variant; Viscosity; Work; aerosolized; cell growth; chemotherapy; crosslink; design; dimer; drug mechanism; gel electrophoresis; improved; in vitro Model; in vivo; inhibitor/antagonist; killings; mutant; programs; protective effect; quinolone resistance; respiratory; tuberculosis treatment; uptake

DESCRIPTION (provided by applicant): The long-term goal of this program is to understand how the quinolones kill Mycobacterium tuberculosis. The present proposal focuses on how these compounds behave in quinolone-gyrase-DNA complexes to cause chromosome fragmentation and rapid cell death. A goal is to identify structural features of the quinolones and gyrase that enhance lethal action, particularly with non-growing bacteria. Preliminary studies have identified structural moieties that make some quinolone derivatives exceptionally active at killing mycobacteria when protein synthesis is blocked, and work with other bacteria indicates that this lethality may arise from quinolone-induced, gyrase-mediated chromosome fragmentation. With new C-8-methoxy fluoroquinolones, neither chromosome fragmentation nor cell death requires ongoing protein synthesis, DNA replication, or aerobic growth, suggesting that these compounds may be able to kill non-growing M. tuberculosis. M. tuberculosis DNA gyrase, the molecular target of quinolones, will be purified and used to study biochemical interactions of quinolones with gyrase-DNA complexes formed with isolated chromosomes (nucleoids) and plasmids. Alteration of gyrase and quinolone structure will be used to probe the mechanism of chromosome fragmentation. Gyrase changes will focus on mutations expected to affect GyrA dimer interactions; quinolone variation will involve the quinolone core ring structure and substituents attached at the N-1, C-6, C-7, and C-8 positions. Chemical cross-linking will be used with ternary drug-enzyme-DNA complexes to characterize aspects of drug binding such as drug-gyrase orientation. Knowledge of how particular quinolone substituents destabilize drug-enzyme-DNA complexes and release lethal DNA breaks will be used to design new quinolones. The most active will be tested for the ability to kill cultured cells after growth has been halted by blocking protein synthesis, by gradual removal of oxygen, and by treatment with nitric oxide. Quinolones that are exceptionally active at fragmenting chromosomes in vitro and killing cultured cells will be examined for lethality with M. tuberculosis in a murine model of infection in which M. tuberculosis growth and growth arrest can be observed. This work is expected to provide information for the design of a new generation of quinolone characterized by rapid killing of non-growing bacterial cells, a property that may shorten treatment of tuberculosis and help limit multidrug-resistant tuberculosis.

描述（由申请人提供）：该计划的长期目标是了解喹诺酮类如何杀死结核分枝杆菌。本提案的重点是这些化合物在喹诺酮 - gyrase-DNA复合物中的行为如何引起染色体破碎和快速细胞死亡。一个目标是鉴定喹诺酮类和回酶的结构特征，从而增强致命作用，尤其是非生长细菌。初步研究已经确定了在蛋白质合成时，使某些喹诺酮衍生物异常活跃在杀死分枝杆菌方面的结构部分，并且与其他细菌一起使用表明这种致死性可能是喹诺酮诱导的旋酶介导的，陀螺酶介导的，陀螺酶介导的染色体片段。使用新的C-8甲氧基氟喹诺酮，染色体破碎和细胞死亡都不需要持续的蛋白质合成，DNA复制或有氧生长，这表明这些化合物可能能够杀死非生长的结核病。结核分枝杆菌DNA回旋酶是喹诺酮的分子靶标，将被纯化并用于研究奎诺酮与用分离的染色体（核苷）和质粒形成的Gyrase-DNA复合物的生化相互作用。回旋酶和喹诺酮结构的改变将用于探测染色体碎片的机理。回旋酶的变化将集中于预期会影响Gyra二聚体相互作用的突变。奎诺酮的变化将涉及N-1，C-6，C-7和C-8位置附加的喹诺酮核心环结构和取代基。化学交联将与三元药物 - 酶-DNA复合物一起使用，以表征药物结合的各个方面，例如药物gyrase取向。了解特定的喹诺酮取代基如何使用药物 - 酶-DNA复合物和释放致命的DNA断裂来设计新的喹诺酮。最活跃的人将通过通过阻断蛋白质合成，通过逐渐去除氧和用一氧化氮处理来阻止蛋白质合成后杀死培养细胞的能力。在体外和杀死培养的细胞中碎裂染色体方面具有异常活跃的喹诺酮，将在鼠类感染模型中检查结核分枝杆菌的致死性，其中可以观察到结核分枝杆菌生长和生长停滞。预计这项工作将为设计新一代的奎诺酮的设计提供信息，其特征在于非生长细菌细胞的快速杀死，该特性可能会缩短结核病的治疗并有助于限制耐多药的结核病。