Expression of sap Operon in NTHI-induced Otitis Media

NTHI诱导的中耳炎中SAP操纵子的表达

• 批准号: 6692403
• 负责人: Kevin M Mason
• 金额: $ 4.81万
• 依托单位: RESEARCH INST NATIONWIDE CHILDREN'S HOSP
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6692403
• 关键词: Haemophilus influenzae; bacteria infection mechanism; bacterial genetics; chinchilla; drug resistance; flow cytometry; gene expression; gene mutation; histology; host organism interaction; microarray technology; neutrophil; operon; otitis media; postdoctoral investigator; virulence

DESCRIPTION (provided by applicant): Bacteria have evolved strategies to resist host defense mechanisms including resistance to antimicrobial peptides (APs). The sap (sensitivity to antimicrobial peptides) operon plays a significant role in this defense, as demonstrated by attenuation of sap operon mutants in animal models. The hypothesis of this proposal is that the sap operon plays a significant role in nontypeable Haemophilus influenzae (NTHI) survival in a chinchilla model of otitis media by maintaining resistance to APs in vivo and by up-regulating expression of specific AP resistance determinants. Expression of the sap operon during the disease course of otitis media or when exposed in vitro to chinchilla neutrophils or neutrophil granule extract will be analyzed by flow cytometry and histology. Mutations in the six genes of the NTHI sap operon will define the functional requirement for each gene in vivo. Finally, microarray analysis will be used to identify genes that determine resistance to APs as a result of sap operon expression. The data generated from these studies will significantly advance the field in understanding how NTHI adapt to the innate immune response in vivo in microenvironments encountered during disease progression and will identify novel virulence mechanisms resulting from sap operon expression that enable NTHI to survive and cause disease.

描述（由申请人提供）：细菌已经进化出抵抗宿主防御机制的策略，包括对抗菌肽（APs）的抗性。树液（对抗菌肽的敏感性）操纵子在这种防御中起着重要作用，正如在动物模型中树液操纵子突变体的衰减所证明的那样。该建议的假设是，果汁操纵子通过维持体内对AP的抗性和上调特异性AP抗性决定因子的表达，在不可分型流感嗜血杆菌（NTHI）在中耳炎栗鼠模型中的存活中发挥重要作用。在中耳炎发病过程中或体外暴露于栗鼠中性粒细胞或中性粒细胞颗粒提取物时，汁液操纵子的表达将通过流式细胞术和组织学进行分析。NTHI sap操纵子的六个基因的突变将决定每个基因在体内的功能需求。最后，微阵列分析将用于鉴定由于sap操纵子表达而决定APs抗性的基因。从这些研究中产生的数据将显著推动该领域了解NTHI如何适应疾病进展过程中遇到的体内微环境中的先天免疫反应，并将确定由sap操纵子表达导致的新的毒力机制，使NTHI能够存活并引起疾病。