Small Molecule Inhibition of Pilus Biogenesis by Pathogenic Bacteria

病原菌对菌毛生物发生的小分子抑制

• 批准号: 9185942
• 负责人: David G Thanassi
• 金额: $ 21.14万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9185942
• 关键词: Acinetobacter baumannii; Address; Adhesions; Adhesives; Adverse effects; Animal Model; Anti-Infective Agents; Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Adhesion; Bacterial Attachment Site; Bacterial Drug Resistance; Binding; Biogenesis; Biological Process; Cell Culture Techniques; Cells; Centers for Disease Control and Prevention (U.S.); Clinic; Communities; Complex; Development; Disease; Drug Kinetics; Drug resistance; Escherichia coli; Exhibits; FDA approved; Goals; Gram-Negative Bacteria; Health; Infection; Invaded; Klebsiella pneumonia bacterium; Lead; Mediating; Membrane; Membrane Proteins; Microbe; Microbial Biofilms; Modeling; Molecular Chaperones; Multi-Drug Resistance; Mus; Pathway interactions; Pharmaceutical Preparations; Pharmacology; Pharmacotherapy; Pilum; Property; Pseudomonas aeruginosa; Race; Resistance; Resistance development; Role; Signal Pathway; Signal Transduction; Site; Specificity; Structure; Surface; System; Testing; Therapeutic; Tissues; Urinary tract; Urinary tract infection; Uropathogenic E. coli; Usher Proteins; VDAC1 gene; Virulence; Virulence Factors; analog; arm; bacterial resistance; base; combat; commensal microbes; disorder prevention; efficacy testing; fluid flow; improved; inhibitor/antagonist; nitazoxanide; novel; pathogen; pathogenic bacteria; pressure; public health relevance; resistance mechanism; small molecule; small molecule therapeutics; targeted agent; therapeutic target; ward

 DESCRIPTION (provided by applicant): Rates of antibiotic resistance among pathogenic bacteria have risen to alarming levels. New strategies and alternatives to traditional antibiotics are needed to combat this health threat and derail the evolutionary arms race leading to resistance. One such alternative is the use of "anti-virulence" therapeutics. Rather than disrupting essential biological processes as for conventional antibiotics, anti-virulence approaches target bacterial systems that are only required to cause disease within the host. Thus, there should be less pressure for the development of resistance. In addition, anti-virulence strategies avoid the detrimental side effects of broad-spectrum antibiotics on the normal bacterial flora. Toward the goal of developing novel alternative therapeutics, we have discovered that the small molecule nitazoxanide (NTZ) inhibits pilus biogenesis by the conserved chaperone/usher pathway in Gram-negative pathogenic bacteria. Pili (fimbriae) are virulence- associated surface structures that mediate adhesion to host cells and colonization of host tissues. Pilus- mediated adhesion is critical for early stages of infection, allowing the bacteria to establish a foothold within the host. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where fluid flow washes away non-adherent pathogens. Following bacterial attachment, pili also modulate host cell signaling pathways, promote or inhibit invasion inside host cells, and mediate bacterial- bacterial interactions leading to formation of community structures such as biofilms. Pili thus function at the host-pathogen interface both to initiate and sustain infection, and represent attractive therapeutic targets. We have found that NTZ inhibits pilus assembly in uropathogenic as well as diarrheagenic strains of Escherichia coli. Moreover, we have determined that the inhibitory effect of NTZ is due to specific interference with proper maturation of the usher protei in the outer membrane. The usher provides the pilus assembly and secretion platform and is essential for pilus biogenesis. This proposal will test the hypothesis that NTZ targets the machinery required for insertion of the usher protein in the outer membrane, and that NTZ analogs will function as potent and specific inhibitors of pilus biogenesis by the CU pathway. The specific aims of this study are to: 1) determine the mechanism of action by which NTZ inhibits pilus biogenesis; 2) identify and characterize the direct target of NTZ; 3) develop and test NTZ-based derivatives with improved potency and pharmacological properties; and 4) test optimized compounds in cell culture and animal models of infection, focusing on uropathogenic E. coli, but also testing Klebsiella pneumoniae. The novel "pilicide" compounds developed by this proposal will represent a new class of anti-infective agents that target virulence factor secretion and the assembly of virulence-associated surface structures in multiple Gram-negative antibiotic threat pathogens.

 描述（由申请人提供）：病原菌对抗生素的耐药性已经上升到令人担忧的水平。需要新的策略和传统抗生素的替代品来对抗这种健康威胁，并破坏导致耐药性的进化军备竞赛。一种这样的替代方法是使用“抗毒性”疗法。与常规抗生素不同，抗毒力方法不是破坏基本的生物过程，而是针对仅在宿主内引起疾病所需的细菌系统。因此，产生耐药性的压力应该较小。此外，抗毒力策略避免了广谱抗生素对正常细菌植物群的有害副作用。为了开发新的替代疗法，我们发现小分子硝唑尼特（NTZ）通过革兰氏阴性病原菌中保守的伴侣/引导途径抑制菌毛生物合成。皮利（菌毛）是毒力相关的表面结构，介导与宿主细胞的粘附和宿主组织的定殖。菌毛介导的粘附对于感染的早期阶段至关重要，使细菌能够在宿主内建立立足点。粘附在宿主组织上的能力对于细菌在诸如泌尿道等液体流动的部位的定植特别重要 洗去未粘附的病原体。在细菌附着后，皮利还调节宿主细胞信号传导途径，促进或抑制宿主细胞内的侵入，并介导细菌-细菌相互作用，导致群落结构如生物膜的形成。因此，皮利在宿主-病原体界面起作用以启动和维持感染，并且代表有吸引力的治疗靶标。我们已经发现NTZ抑制尿路致病性以及致肠出血性大肠杆菌菌株中的菌毛组装。此外，我们已经确定NTZ的抑制作用是由于特异性干扰外膜中的usher蛋白的适当成熟。引导器提供菌毛组装和分泌平台，是菌毛生物发生所必需的。该提议将测试NTZ靶向将引导蛋白插入外膜所需的机制的假设，并且NTZ类似物将通过CU途径作为菌毛生物发生的有效和特异性抑制剂起作用。本研究的具体目的是：1）确定NTZ抑制菌毛生物发生的作用机制; 2）鉴定和表征NTZ的直接靶点; 3）开发和测试具有改进的效力和药理学特性的基于NTZ的衍生物;以及4）在细胞培养和动物感染模型中测试优化的化合物，重点是尿路致病性大肠杆菌。大肠杆菌，但也测试肺炎克雷伯氏菌。由该提议开发的新型“杀菌毛剂”化合物将代表一类新的抗感染剂，其靶向多种革兰氏阴性抗生素威胁病原体中的毒力因子分泌和毒力相关表面结构的组装。