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）：病原菌中的抗生素耐药性已经上升到令人震惊的水平，需要新的策略和传统抗生素的替代品来应对这种健康威胁并破坏导致耐药性的进化军备竞赛。 “抗毒力”疗法不像传统抗生素那样破坏基本的生物过程，而是针对仅在宿主体内引起疾病的细菌系统，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菌群的不良副作用，为了开发新型替代疗法的目标，我们发现小分子硝唑尼特（NTZ）通过保守伴侣抑制菌毛生物发生。革兰氏阴性致病菌（菌毛）中的 /usher 途径是介导宿主细胞粘附和菌毛定植的毒力相关表面结构。介导的粘附对于感染的早期阶段至关重要，使细菌能够在宿主体内建立立足点。粘附到宿主组织上的能力对于定植于尿道等液体流动部位的细菌尤其重要。 细菌附着后，菌毛还可以调节宿主细胞信号通路，促进或抑制宿主细胞内的入侵，并介导细菌与细菌之间的相互作用，从而形成菌毛等群落结构，从而在宿主细胞中发挥作用。病原体相互作用以引发和维持感染，并且是有吸引力的治疗靶点，我们发现 NTZ 可以抑制尿路致病性和腹泻性大肠杆菌菌株的菌毛组装。 NTZ 的作用是由于对外膜引座蛋白的正常成熟产生特异性干扰。引座蛋白提供了菌毛组装和分泌平台，并且对于菌毛生物发生至关重要。该提案将检验 NTZ 靶向插入菌毛所需的机制的假设。外膜中的引导蛋白，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。本研究的具体目的是：1) 确定其作用机制。 NTZ 抑制菌毛生物发生；2) 识别和表征 NTZ 的直接靶点；3) 开发和测试具有改进效力和药理学特性的 NTZ 衍生物；4) 在细胞培养和动物感染模型中测试优化的化合物，重点关注泌尿道致病性。该提案开发的新型“pilicide”化合物将代表一类针对毒力因子分泌和感染的新型抗感染药物。多种革兰氏阴性抗生素威胁病原体中毒力相关表面结构的组装。