Role of OxyR in P. aeruginosa Biofilm Resistance to H202

OxyR 在铜绿假单胞菌生物膜 H2O2 抗性中的作用

• 批准号: 6831086
• 负责人: DANIEL J. HASSETT
• 金额: $ 30.31万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6831086
• 关键词: Pseudomonas aeruginosa; aminoglycoside antibiotics; bacterial disease; bacterial genetics; bacterial proteins; biofilm; cystic fibrosis; disease /disorder model; drug resistance; host organism interaction; human subject; hydrogen peroxide; laboratory mouse; leukocyte oxidative burst; microorganism disease chemotherapy; mutant; neutrophil; patient oriented research; protein structure function; transcription factor; virulence

DESCRIPTION (provided by applicant): In cystic fibrosis (CF) airway disease, there is compelling evidence for two distinct clinical stages, an oxidative phase (early-stage CF) and an anaerobic phase (chronic, late-stage CF). Within the thick mucus lining the CF airways, the bacteria grow as a "biofilm," a form of development that affords organisms the luxury of enhanced resistance to antibiotics and biocides. The early oxidative phase is based upon a rapid and dramatic influx of neutrophils to the upper airways, an event triggered by bacterial infection. When stimulated, these professional phagocytes mount a potent "respiratory burst," an antimicrobial product from which is hydrogen peroxide (H202). In fact, neutrophils can generate millimolar levels of H202 within the phagolysomal vacuole. In contrast, H202 levels in blood are nearly 1000-fold lower. Surprisingly, a mutant of the major CF pathogen, Pseudomonas aeruginosa, lacking the H202-responsive transactivator, OxyR, is exquisitely sensitive to H202 and the bacteria perish even in the presence of blood H202 levels (micromolar range). Were OxyR to be compromised during human infection, bacteria would be unable to elicit a systemic infection because they would die via H202-mediated killing. Therefore, the goal of this proposal is to determine if OxyR of P. aeruginosa could serve as a drug target during various P. aeruginosa infections. The goals of this proposal are to (i) define a role for OxyR in animal virulence and resistance to human neutrophils, (ii) define the lesions that evoke exquisite sensitivity to H202 in the OxyR mutant and what OxyR-controlled gene products contribute to maximal or minimal protection, and (iii) determine whether OxyR is critical for survival of biofilm bacteria to H202 and aminoglycosides.

描述（由申请人提供）：在囊性纤维化（CF）气道疾病中，有令人信服的证据证明两个不同的临床阶段，一个氧化相（早期CF）和一个厌氧相（慢性，晚期CF）。在CF气道衬砌的浓稠粘液中，细菌作为“生物膜”生长，这种发育形式可为生物提供增强对抗生素和杀菌剂的耐药性的奢侈。早期氧化阶段基于中性粒细胞的快速而急剧流向上呼吸道，这是由细菌感染触发的事件。当受到刺激时，这些专业的吞噬细胞会安装有效的“呼吸爆发”，这是一种抗菌产物，从中是过氧化氢（H202）。实际上，嗜中性粒细胞可以在吞噬性液泡中产生毫米水平的H202。相比之下，血液中的H202水平低接近1000倍。令人惊讶的是，缺乏H202响应反式激活器Oxyr的主要CF病原体的铜绿假单胞菌的突变体对H202非常敏感，即使存在血液H202水平（Micrololar范围），细菌即使存在。如果在人类感染期间被oxyr被损害，细菌将无法引起全身感染，因为它们会通过H202介导的杀伤而死。因此，该提案的目的是确定在各种铜绿假单胞菌感染期间是否可以用作药物靶标。该提案的目标是（i）定义oxyr在动物毒力中的作用和对人嗜中性粒细胞的抗性，（ii）定义了对Oxyr突变体中对H202的敏感性的病变，以及oxyr控制的基因产物的最大或最小保护性的BACTER的氧化物以及（III）是否有助于HAF，以及（iii）是否存活，以及（iii III）。氨基糖苷。