Metabolic regulation in otitis media

中耳炎的代谢调节

• 批准号: 7697052
• 负责人: Dayle Anita Daines
• 金额: $ 32.82万
• 依托单位: MERCER UNIVERSITY MACON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-09 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7697052
• 关键词: Address; Affect; Air; Alleles; Antibiotic Therapy; Antibiotics; Antitoxins; Attenuated; Binding; Biochemical; Biological Assay; Biological Models; Cell Cycle; Child; Chinchilla (genus); Chronic; Chronic Disease; Clinical; Complex; Data; Disease; Environment; Exhibits; Factor For Inversion Stimulation Protein; Failure; Gene Family; Genes; Genetic; Growth; Haemophilus influenzae type b bacteria; Histology; Human; In Vitro; Infection; Intervention; Language Development; Lead; Life; Liquid substance; Measures; Mediating; Metabolic; Microbial Biofilms; Modeling; Molecular; Mucous Membrane; Mutate; Nontypable Haemophilus influenza; Nutrient; Operon; Organism; Otitis Media; Parasites; Parents; Pathogenesis; Pathway interactions; Patients; Peptide Hydrolases; Pharmacologic Substance; Phenotype; Plasmids; Promoter Regions; Proteins; Public Health; Recurrence; Regulation; Relative (related person); Replication Origin; Research; Ribonucleases; Stress; Testing; Time; Tissue Model; Tissues; Toxin; Transcriptional Regulation; Transmission Electron Microscopy; Treatment Failure; Upper respiratory tract; Vaccines; antimicrobial; clinically significant; deafness; ear infection; human tissue; improved; in vivo; middle ear; mutant; new therapeutic target; novel; nuclease; promoter; protein complex; public health relevance

DESCRIPTION (provided by applicant): Nonencapsulated (nontypeable) Haemophilus influenzae (NTHi) are human-adapted commensal organisms that can also cause chronic mucosal infections, particularly otitis media. Since NTHi are not susceptible to the routinely-administered Hib vaccine, these infections are usually treated with antibiotics. Many children exhibit recurrent otitis media caused by NTHi despite antibiotic treatment, and these episodes can lead to deafness and language development delays in early life. Although the ability to form biofilms has been implicated in persistent infections, the exact molecular mechanism by which NTHi causes chronic disease is not fully understood. NTHi contain a set of four highly conserved gene pairs termed toxin-antitoxin (TA) loci. Our preliminary data shows that the deletion of two of these gene pairs significantly reduces the ability of the organism to cause long-term infections in a primary human tissue model. Our hypothesis is that these four TA loci are involved in protease-mediated metabolic regulation that allows the organism to enter a state of growth arrest precipitated by stress (such as antibiotic therapy or nutrient limitation), and this enhances their ability to survive under these suboptimal conditions. Once conditions improve (e.g. cessation of antibiotic treatment, or nutrient upshift), bacterial growth resumes. Since most antibiotics target essential biosynthetic pathways that are not utilized during growth arrest, this mechanism could explain the observed clinical failure in children with recurrent otitis media, and result in new targets for the treatment of chronic infections. To investigate this, we aim to a) progressively delete all four TA loci from two different NTHi strains; b) assess the ability of these mutants to survive in long-term infections of a primary human tissue model grown at the air-liquid interface, and c) analyze the mutants that were found to be significantly attenuated for persistence in the chinchilla model of otitis media. Because TA loci appear in hundreds of different bacterial species, in addition to discovering novel targets for immunological or pharmacological intervention for those patients that exhibit chronic disease, these studies have implications for the treatment of many other organisms that persist within a host or in the environment. PUBLIC HEALTH RELEVANCE: antibiotic treatment failure in children that results in recurrent middle ear infections (otitis media). These episodes can lead to deafness as well as language development delays. Our research could lead to the identification of new targets for vaccines or pharmaceuticals that would synergize with existing treatments for those patients that exhibit chronic otitis media.

描述（由申请人提供）：非封装（不可替代的）流感嗜血杆菌（NTHI）是人适应的共生生物，也可能引起慢性粘膜感染，尤其是耳炎培养基。由于NTHI不容易受到常规化的HIB疫苗的影响，因此这些感染通常被抗生素治疗。尽管治疗抗生素治疗，许多儿童表现出由NTHI引起的复发性中耳炎，这些事件可能导致早期生活中的耳聋和语言发展延迟。尽管形成生物膜的能力已与持续感染有关，但NTHI引起慢性疾病的确切分子机制尚未完全了解。 NTHI包含一组四个高度保守的基因对，称为毒素 - 抗毒素（TA）基因座。我们的初步数据表明，其中两个基因的缺失显着降低了生物体在原发性人体组织模型中引起长期感染的能力。我们的假设是，这四个TA基因座参与了蛋白酶介导的代谢调节，该调节使生物体能够进入压力（例如抗生素治疗或营养限制）沉淀的生长停滞状态，这增强了它们在这些次次次次次次次次次次次的情况下生存的能力。一旦条件改善（例如停止抗生素治疗或营养升级），细菌生长就会恢复。由于大多数抗生素靶向生长停滞期间未利用的必需生物合成途径，因此该机制可以解释观察到的复发性中耳炎儿童的临床衰竭，并为治疗慢性感染带来新的靶标。为了调查这一点，我们旨在a）从两个不同的nthi菌株中逐渐删除所有四个TA基因座； b）评估这些突变体在空气界面上生长的原发性人体组织模型长期感染中生存的能力，以及c）分析发现在耳炎培养基的龙猫模型中发现持久性的突变体。由于TA基因座出现在数百种不同的细菌物种中，因此除了发现表现出慢性疾病的患者的免疫或药理干预措施外，这些研究对治疗许多其他宿主或环境中持续存在的生物具有影响。公共卫生相关性：儿童的抗生素治疗失败导致中耳感染（中耳炎）。这些情节可能导致耳聋以及语言发展延迟。我们的研究可能导致鉴定出针对疫苗或药物的新靶标，这些疫苗或药物将与现有的治疗方法为那些表现出慢性中耳炎的患者协同作用。