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，有令人信服的证据表明两个不同的临床阶段：氧化阶段（早期 CF）和厌氧阶段（慢性、晚期 CF）。在 CF 气道内衬的浓稠粘液中，细菌以“生物膜”的形式生长，这种发育形式使生物体能够增强对抗生素和杀菌剂的抵抗力。早期氧化阶段是基于中性粒细胞快速而剧烈地流入上呼吸道，这是由细菌感染引发的事件。当受到刺激时，这些专业吞噬细胞会产生强大的“呼吸爆发”，这是一种抗菌产物，其中产生过氧化氢（H2O2）。事实上，中性粒细胞可以在吞噬溶酶体液泡内产生毫摩尔水平的H2O2。相比之下，血液中的 H2O2 水平低了近 1000 倍。令人惊讶的是，主要 CF 病原体铜绿假单胞菌的突变体缺乏 H2O2 响应反式激活因子 OxyR，对 H2O2 极其敏感，并且即使在血液 H2O2 水平（微摩尔范围）存在的情况下，细菌也会死亡。如果 OxyR 在人类感染过程中受到损害，细菌将无法引发全身感染，因为它们会通过 H2O2 介导的杀伤作用而死亡。因此，本提案的目标是确定铜绿假单胞菌的 OxyR 是否可以作为各种铜绿假单胞菌感染期间的药物靶点。该提案的目标是 (i) 定义 OxyR 在动物毒力和对人类中性粒细胞的抗性中的作用，(ii) 定义在 OxyR 突变体中引起对 H2O2 高度敏感性的病变，以及 OxyR 控制的基因产物对最大程度发挥作用的贡献。或最低限度的保护，以及(iii)确定OxyR对于生物膜细菌对H 2 O 2 和氨基糖苷类的存活是否至关重要。