Nitrothiazolides:Broad-Spectrum Category B Anti-parasitic/bacterial Therapeutics

硝基噻唑类：广谱 B 类抗寄生虫/细菌治疗药物

• 批准号: 7471459
• 负责人: PAUL Stokes HOFFMAN
• 金额: $ 50.1万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7471459
• 关键词: Acetyl Coenzyme A; Adverse effects; Animal Model; Animals; Anions; Bacteria; Biochemical; Biological; Biological Assay; Biological Availability; Bioterrorism; Campylobacter jejuni; Categories; Cell Line; Chemical Structure; Chemicals; Chemistry; Class; Clinic; Clinical Trials; Clostridium; Clostridium difficile; Clostridium perfringens; Collection; Complex; Cryptosporidium; Cryptosporidium parvum; Crystallography; Data; Development; Dose; Drug Kinetics; Drug resistance; Entamoeba histolytica; Enteral; Enzymatic Biochemistry; Enzymes; Escherichia coli EHEC; Evaluation; Event; Exhibits; Ferredoxin; Flavodoxin; Food; Generations; Generic Drugs; Giardia lamblia; Goals; Hamsters; Human; In Vitro; Industry; Infection; Inhibitory Concentration 50; Intestines; Kinetics; Knowledge; Laboratories; Lead; Legal patent; Mammalian Cell; Measures; Medicine; Metabolic; Metabolism; Metronidazole; Metronidazole resistance; Microbiology; Modeling; Modification; Mutation; National Institute of Allergy and Infectious Disease; Newborn Infant; Organism; Oxidation-Reduction; Oxidoreductase; Pan Genus; Parasites; Parasitology; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phase; Process; Prodrugs; Production; Property; Prophylactic treatment; Propionibacterium acnes; Protocols documentation; Publishing; Pyruvate; Pyruvate synthase; Pyruvates; Range; Research; Research Personnel; Screening procedure; Site; Staging; Testing; Therapeutic; Therapeutic Corynebacterium Parvum; Therapeutic Index; Thiamine Pyrophosphate; Thiazoles; Titrations; Toxic effect; Toxicology; Treatment Efficacy; United States Food and Drug Administration; Universities; Variant; Virginia; Virulence; Water; Work; X-Ray Crystallography; Yeasts; base; biodefense; cofactor; commercialization; cytotoxicity; design; drug development; drug metabolism; enteric pathogen; enteroaggregative Escherichia coli; fitness; improved; inhibitor/antagonist; mecarzole; mouse model; nitazoxanide; novel; pathogen; pre-clinical; programs; pyruvate dehydrogenase; resistance mechanism; salicylate; scale up; tool

DESCRIPTION (provided by applicant): The research focus of the proposed work is to develop second generation broad spectrum 5-nitrothiazolide therapeutics against Category B priority food and water borne pathogens Cryptosporidium parvum, Entamoeba histolytica, Giardia intestinalis, Campylobacter jejuni and Clostridium spp. All of these human pathogens share a common and essential metabolic enzyme of central metabolism, pyruvate ferredoxin oxidoreductase (PFOR) that is recognized as a good druggable target. Our published and preliminary studies establish that generic drug nitazoxanide (NTZ), a 5-nitrothiazolide which is FDA approved for treatment of infections caused by C. parvum and G. intestinalis, selectively inhibits PFOR in all of the target pathogens by a novel mechanism. Mechanistic studies show that the nitrothiazolide anion dissociates the pyruvate-thiamine pyrophosphate transition intermediate and thereby blocking formation of acetyl-CoA and reducing power. In the process, NTZ is protonated to an inactive form. The biological activity of nitazoxanide is highly pH dependent and the goal of the proposed studies is to develop derivatives which are more potent at lower pH. The pipeline approach to developing second generation broad spectrum therapeutics includes the following specific aims: (i) synthesize new lead compounds driven by knowledge of pKa and structural data from X-ray crystallography and screen for inhibitory activity in medium throughput PFOR 96 well assay (IC50 and Ki); (ii)screen active leads for biological activity against target pathogens in vitro (MIC, MBC, MLC); (iii) determine therapeutic efficacy of potent leads in animal infection models; and (iv) progress viable candidate drugs through product development, toxicology and scale up for clinical trials. Two unexpected caveats of this novel target and inhibitory mechanism are (i) low likelihood for development of drug resistance and (ii) weak activity against the NAD-pyruvate dehydrogenase of enteric pathogens - loss of fitness and colonization efficiency. Successful completion of these studies will produce second generation broad spectrum nitrothiazolide therapeutics with increased bioavailability and potency against Category B intestinal parasites and bacteria (broad spectrum anti-diarrheal agent) that can be evaluated clinically for prophylaxis against and primary treatment of infections caused by bioterrorism activities or natural events.

描述（由申请人提供）： 拟议工作的研究重点是开发第二代广谱 5-硝基噻唑烷疗法，针对 B 类优先食品和水源性病原体小隐孢子虫、溶组织内阿米巴、肠贾第虫、空肠弯曲杆菌和梭状芽胞杆菌。所有这些人类病原体都有一种共同且重要的中央代谢酶，即丙酮酸铁氧还蛋白氧化还原酶（PFOR），它被认为是良好的药物靶标。我们已发表的初步研究表明，仿制药硝唑尼特 (NTZ) 是一种 5-硝基噻唑烷，已被 FDA 批准用于治疗微小念珠菌和肠杆菌引起的感染，通过一种新机制选择性抑制所有目标病原体中的 PFOR。机理研究表明硝基噻唑阴离子解离丙酮酸-硫胺素焦磷酸过渡中间体，从而阻止乙酰辅酶A的形成并降低功率。在此过程中，NTZ 被质子化为非活性形式。硝唑尼特的生物活性高度依赖于 pH 值，本研究的目标是开发在较低 pH 值下更有效的衍生物。开发第二代广谱治疗药物的管道方法包括以下具体目标：（i）通过 X 射线晶体学的 pKa 知识和结构数据合成新的先导化合物，并在中等通量 PFOR 96 孔测定中筛选抑制活性（IC50 和 Ki）； (ii) 筛选活性先导化合物的体外针对目标病原体的生物活性（MIC、MBC、MLC）； (iii) 确定强效先导化合物在动物感染模型中的治疗效果； (iv) 通过产品开发、毒理学和临床试验规模化，开发可行的候选药物。这种新的靶点和抑制机制有两个意想不到的警告：(i) 产生耐药性的可能性很低，(ii) 针对肠道病原体的 NAD-丙酮酸脱氢酶的活性较弱——适应性和定植效率的损失。这些研究的成功完成将产生第二代广谱硝基噻唑类药物，该药物具有更高的生物利用度和对抗 B 类肠道寄生虫和细菌的效力（广谱止泻剂），可用于临床评估，用于预防和初步治疗生物恐怖活动或自然事件引起的感染。