Therapeutics for Drug-Resistant Bacteria: Myxopyronins

耐药细菌的治疗方法：粘菌素

• 批准号: 8476980
• 负责人: RICHARD H. EBRIGHT
• 金额: $ 114.02万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8476980
• 关键词: Address; Adsorption; Animal Model; Anti-Bacterial Agents; Antibiotics; Antitubercular Agents; Bacterial Infections; Bacterial RNA; Binding; Binding Sites; Biological Assay; Biological Availability; Cells; Clinical; Clostridium difficile; Complex; Cysteine; DNA; DNA-Directed RNA Polymerase; Drug Kinetics; Drug Resistant Tuberculosis; Drug resistance; Drug resistance in tuberculosis; Elements; Enterobacter cloacae; Enterococcus faecalis; Evaluation; Excretory function; Exhibits; Extreme drug resistant tuberculosis; Future; Genetic Transcription; Homology Modeling; In Vitro; Infection; Kilogram; Mammalian Cell; Mediating; Metabolism; Modification; Multi-Drug Resistance; Mycobacterium tuberculosis; Preparation; Procedures; Production; Public Health; Pyrones; RNA Polymerase I; RNA Polymerase II; RNA Polymerase III; Recombinants; Resistance; Rifabutin; Rifampin; Rifamycins; Staphylococcus aureus; Streptococcus pneumoniae; Structure; Technology Transfer; Therapeutic; Toxic effect; Toxicity Tests; Water; Work; analog; base; biodefense; cytotoxicity; design; drug candidate; drug resistant bacteria; efficacy testing; in vivo; inhibitor/antagonist; interfacial; large scale production; methicillin resistant Staphylococcus aureus; mouse model; pathogen; radiochemical; rifapentine; safety testing

DESCRIPTION (provided by applicant): Myxopyronin (Myx) is an ?-pyrone antibiotic that inhibits bacterial RNA polymerase (RNAP) through interactions with the RNAP "switch region," a structural element that mediates conformational changes required for RNAP to bind and retain the DNA template in transcription. Myx does not inhibit eukaryotic RNAP I, RNAP II, or RNAP III. Myx exhibits potent antibacterial activity against Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Enterobacter cloacae, and Clostridium difficile in culture. Myx exhibits no cross-resistance with the inhibitors of bacterial RNAP in current clinical use in therapy of bacterial infection (the rifamycin antibacterial agents, rifampin, rifapentine, and rifabutin), and exhibits no or minimal cross-resistance with other inhibitors of bacterial RNAP under evaluation for future clinical use in therapy of bacterial infection. In preliminary work, we have shown that Myx functions by inhibiting bacterial RNAP through a binding site and mechanism that are different from those of rifamycin antibacterial agents. We have determined a crystal structure of a bacterial RNAP in complex with Myx, and we have constructed homology models of pathogen RNAP in complex with Myx. The crystal structure and homology models suggest alterations to the structure of Myx that are expected (i) specifically to increase potency against M. tuberculosis RNAP, exploiting a binding-site cysteine residue present in M. tuberculosis RNAP, or (ii) generally to increase potency against a broad spectrum of bacterial RNAP, exploiting a binding-site interfacial water molecule, and other structural features, present in a broad spectrum of bacterial RNAP. In further preliminary work, we have optimized procedures for total synthesis of Myx and Myx analogs, developed procedures for preparation of recombinant pathogen RNAP, and developed procedures for fluorescent and radiochemical assays of pathogen RNAP. We propose to leverage the mechanistic and structural information, synthetic procedures, and assay procedures developed in preliminary work in order to design, synthesize, and evaluate: (i) Myx analogs with increased efficacy against multidrug-resistant and extensively-drug-resistant M. tuberculosis, and (ii) Myx analogs with increased efficacy against a broad spectrum of drug-resistant pathogens. Analogs will be evaluated for inhibition of RNAP in vitro, for antibacterial activity in culture, and for cytotoxicity against mammalian cells in culture. Analogs of high promise will be evaluated for antibacterial activity in small-animal models of infection, and analogs of highest promise will be evaluated for bioavailability, pharmacokinetics, toxicity, and ability to scale synthesis. Primary target pathogens include: M. tuberculosis H37Rv and MDR/XDR, Staphylococcus aureus MSSA and MRSA, Enterococcus faecalis VSE and VRE, Streptococcus pneumoniae, Enterobacter cloacae, and Clostridium difficile. Drug-resistant bacterial infections are a major and growing threat. The proposed work is expected to provide two classes of new drug candidates: (1) antibacterial agents effective against multi-drug-resistant and extensively-drug-resistant tuberculosis, and (2) antibacterial agents effective against a broad spectrum of drug-resistant bacterial pathogens, including both public-health-relevant bacterial pathogens and biodefense-relevant bacterial pathogens.

描述（由申请人提供）：霉菌蛋白（Myx）是一种？ - 吡咯酮抗生素，通过与RNAP“开关区域”相互作用来抑制细菌RNA聚合酶（RNAP），这是一种结构性元素，它介导了RNAP所需的构象变化，以粘结和保留DNA在转录中的DNA模板。 Myx不会抑制真核RNAP I，RNAP II或RNAP III。 MYX具有针对结核分枝杆菌，金黄色葡萄球菌，肺炎链球菌，粪便肠球菌，肠杆菌和艰难梭状芽孢杆菌的有效抗菌活性。 MYX在当前在细菌感染治疗中的临床用途中没有与细菌RNAP的抑制剂表现出任何交叉抗性（利福米霉素抗菌剂，利福平，利福平和利福丁蛋白），并且没有或最小的交叉抗性，可与其他抑制剂进行细菌的临床疗法临床疗法，从而表现出任何或最少的交叉抑制作用。在初步工作中，我们已经通过结合位点抑制细菌RNAP和机制，与利福米霉素抗菌剂不同。我们已经确定了与Myx复合物中细菌RNAP的晶体结构，并且我们构建了与Myx复合物中病原体RNAP的同源模型。晶体结构和同源模型表明，预期的（i）专门提高了针对结核分枝杆菌RNAP的效力的变化，从而利用了结核分枝杆菌RNAP中存在的结合位置的半胱氨酸残基，或（ii）通常增加了针对广泛的效力，并增加了与细菌rnap的广泛效力，并相互利用了构造的分子群体群体插图群体互联网群体互联网群体群体群体互联网，细菌RNAP的光谱。在进一步的初步工作中，我们采用了用于完全合成MYX和MYX类似物的程序，开发了准备重组病原体RNAP的程序，并开发了用于病原体RNAP的荧光和放射化学测定的程序。我们建议在初步工作中开发的机械和结构信息，合成程序和测定程序，以设计，合成和评估：（i）对抗多药和广泛毒品抗性的M. perberculisosis和（II）对毒品的抗性疗效的Myx类似物提高了抗性和广泛毒品的耐药性。将评估类似物在体外抑制RNAP，培养中的抗菌活性以及培养中针对哺乳动物细胞的细胞毒性。在小动物的感染模型中，将评估高希望的类似物的类似物，并将评估具有最高诺言的类似物的生物利用度，药代动力学，毒性和缩放合成能力。主要的靶病原体包括：结核杆菌H37RV和MDR/XDR，金黄色葡萄球菌MSSA和MRSA，MRSA，Faecalis肠球菌VSE和VRE，肺炎链球菌，肠杆菌，肠杆菌肠杆菌和障碍。耐药的细菌感染是主要的威胁。预计该提议的工作将提供两类新药候选者：（1）抗菌剂有效抗多药耐药性和广泛的药物耐药性结核病，以及（2）抗菌剂，抗菌剂可抗药物耐药性细菌病原体，包括两种公共健康型培养基，包括抗毒性的细菌症状。