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（由适用提供）：致病细菌之间的抗生素抗性速率已提高到令人震惊的水平。需要采取新的策略和替代抗生素的替代品来应对这种健康威胁并脱轨，从而导致抵抗。这样的选择是使用“抗病毒”疗法。抗病毒方法不是破坏基本生物学过程，而是针对仅在宿主内引起疾病的细菌系统的方法。这是阻力发展的压力应该较小。此外，抗病毒策略避免了广谱抗生素对正常细菌菌群的有害副作用。为了开发新的替代疗法的目的，我们发现小分子硝酸分子（NTZ）通过革兰氏阴性的致病细菌中保守的伴侣/usher途径抑制菌毛生物发生。 pili（fimbriae）是与宿主细胞中位粘附和宿主组织定植的病毒相关的表面结构。 PILUS介导的粘合剂对于感染的早期阶段至关重要，从而使细菌在宿主内建立了立足点。粘附于托管组织的能力对于殖民地（例如尿路）的细菌尤其重要，其中流体流动 洗去非粘附的病原体。细菌附着后，PILI还调节宿主细胞信号通路，促进或抑制宿主细胞内的注射，并介导细菌相互作用，从而导致形成社区结构（例如生物膜）。因此，PILI在宿主 - 病原体界面上起启动和维持感染的功能，并代表有吸引力的治疗靶标。我们发现，NTZ抑制了大肠杆菌的尿道病和腹泻菌株中的吡咯组装。此外，我们已经确定了NTZ的抑制作用是由于特异性干扰了外膜在外膜中的适当成熟。 Usher提供了pyrus组装和分泌平台，对于pyrus生物发生至关重要。该建议将检验以下假设：NTZ靶向插入Usher蛋白在外膜中所需的机械，并且NTZ类似物将充当CU途径的Pyrus生物发生的潜在和特定抑制剂。这项研究的具体目的是：1）确定NTZ抑制Pyrus生物发生的作用机理； 2）识别并表征NTZ的直接目标； 3）开发和测试基于NTZ的衍生物具有提高的效力和药物特性； 4）在感染的细胞培养和动物模型中测试优化的化合物，重点是肝癌大肠杆菌，但还测试了肺炎克雷伯氏菌。该提案开发的新型“硫化剂”化合物将代表一类新的抗感染剂，这些抗感染剂靶向病毒因子分泌和在多种革兰氏阴性抗生素威胁病原体中与病毒相关的表面结构组装。