CFTR Expression and Function in Human Neutrophils

CFTR 在人中性粒细胞中的表达和功能

• 批准号: 7676843
• 负责人: GUOSHUN WANG
• 金额: $ 34.27万
• 依托单位: LSU HEALTH SCIENCES CENTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7676843
• 关键词: Affect; Anions; Bacteria; Caucasians; Caucasoid Race; Cells; Chloride Channels; Chloride Ion; Chlorides; Cyclic AMP; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Data; Defect; Epithelial Cells; Genes; Hereditary Disease; Human; Hydrogen Peroxide; Hypochlorous Acid; Knowledge; Life; Link; Organelles; Oxidants; Oxidases; Peroxidases; Phagocytes; Phagocytosis; Phagolysosome; Play; Production; Publications; Reaction; Regulation; Rest; Role; base; chlorination; cystic fibrosis patients; effective therapy; killings; microbicide; neutrophil; pathogen

DESCRIPTION (provided by applicant): Neutrophilic polymorphonuclear leukocytes (PMNs or neutrophils), the main phagocytes responsible for elimination of pathogens and cell debris, synthesize and maintain abundant myeloperoxidase (MPO). This special oxidase converts hydrogen peroxide and chloride anion to hypochlorous acid (HOCI), one of the most potent oxidants for bacterial killing. Even though this reaction can occur extracellularly if MPO is secreted or leaked out, it is largely contained within PMN phagolysosomes. Our preliminary data and publication have demonstrated that cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP- regulated chloride channel, is expressed in neutrophils and their phagolysosomes. Importantly, the gene defects in PMNs from cystic fibrosis (CF) patients have an impaired HOCI production in phagolysosomes. Such a deficiency affects the chlorination and killing of phagocytosed bacteria. Based on these findings, we hypothesize that CFTR plays a pivotal role in regulating chloride levels in phagolysosomes. Therefore, a dysfunctional CFTR in CF may affect the chloride availability to this organelle, thus compromising the bacterial killing capacity of the PMNs. The long-term objective of this proposal is to confirm CFTR expression in PMNs and its function in chloride secretion to phagolysosomes. We put forward four specific aims: 1) to identify the subcellular localization of CFTR in resting neutrophils from normal subjects and CF patients; 2) to characterize CFTR function in isolated phagolysosomes from normal and CF neutrophils; 3) to examine the role of CFTR in regulation of phagolysosomal chloride concentration in live neutrophils; and 4) to compare the microbicidal abilities of normal, CF and MPO-deficient neutrophils. By completion of the four specific aims, we will understand the importance of CFTR in secretion of chloride anion to phagolysosomes. Such studies will extend our current understanding of the role played by CFTR in non-epithelial cells and establish the link of a dysfunctional chloride channel function with the neutrophil bacterial killing capacity. Apparently, the obtained knowledge is highly relevant to searching effective therapies for the treatment of CF, the most fatal genetic disease in Caucasians.

性状（由申请方提供）：嗜中性多形核白细胞（PMN或中性粒细胞）是负责消除病原体和细胞碎片的主要吞噬细胞，合成并维持丰富的髓过氧化物酶（MPO）。这种特殊的氧化酶将过氧化氢和氯阴离子转化为次氯酸（HOCI），这是杀死细菌的最有效的氧化剂之一。即使这种反应可以发生在细胞外，如果MPO分泌或泄漏出来，它主要包含在PMN吞噬溶酶体。我们的初步数据和出版物表明，囊性纤维化跨膜传导调节因子（CFTR），一种cAMP调节的氯离子通道，在中性粒细胞及其吞噬溶酶体中表达。重要的是，囊性纤维化（CF）患者PMN中的基因缺陷使吞噬溶酶体中的HOCI产生受损。这种缺陷会影响氯化和杀灭被吞噬的细菌。基于这些发现，我们假设CFTR在调节吞噬溶酶体中的氯离子水平中起着关键作用。因此，CF中功能失调的CFTR可能会影响该细胞器的氯化物可用性，从而损害PMNs的细菌杀伤能力。这项建议的长期目标是确认CFTR在中性粒细胞中的表达及其在吞噬溶酶体的氯化物分泌中的功能。我们提出了四个具体目标：1）确定CFTR在正常受试者和CF患者的静息中性粒细胞中的亚细胞定位; 2）表征CFTR在正常和CF中性粒细胞的分离吞噬溶酶体中的功能; 3）检查CFTR在调节活中性粒细胞中吞噬溶酶体氯化物浓度中的作用; 4）比较正常、CF和MPO缺陷中性粒细胞的杀微生物能力。通过完成这四个具体目标，我们将了解CFTR在分泌氯阴离子到吞噬溶酶体中的重要性。这些研究将扩展我们目前对CFTR在非上皮细胞中所起作用的理解，并建立功能失调的氯离子通道功能与中性粒细胞细菌杀伤能力的联系。显然，获得的知识是高度相关的寻找有效的治疗CF，最致命的遗传性疾病的白人。