Calcium dependent mechanisms of neutrophil dysfunction that contribute to cystic fibrosis pathobiology

 描述（由申请人提供）：囊性纤维化（CF）是一种常染色体隐性遗传疾病，由囊性纤维化跨膜传导调节因子（cftr）基因突变引起，特征为上皮细胞离子转运异常、粘液粘稠、慢性细菌感染和气道炎症加重。引起肺部感染的细菌，包括新洋葱伯克霍尔德氏菌（B. cenocepacia）对CF患者是致命的威胁。B。新洋葱虫对抗生素有抗性，宿主吞噬细胞不能清除感染，导致严重的炎症。中性粒细胞在控制肺部感染和炎症中发挥重要作用，然而在CF患者中;中性粒细胞不能根除细菌并促进炎症。CFTR是已知调节肺中上皮液体转运的氯离子通道。CFTR在吞噬细胞中的功能，以及CFTR缺乏如何影响吞噬细胞的炎症活性尚不清楚。CFTR突变已被证明直接改变气道上皮细胞中的钙（Ca 2+）稳态，但该突变对中性粒细胞Ca 2+依赖性功能的影响仍有待确定。在CF中性粒细胞中，我们发现Ca 2+信号沿着Ca 2+通道TRPM 2增加，而活性氧（ROS）的产生和NETosis不足。因此，我们假设CFTR突变导致细胞质中Ca 2+释放增加。改变的Ca 2+稳态反过来正调节Ca 2+依赖性炎性中性粒细胞功能，但下调NADPH活性，导致中性粒细胞缺陷性细菌杀伤。为了验证这个假设，我们将：1）。确定CFTR突变如何影响中性粒细胞中的钙信号通路2）。定义轴TRPM 2/NADPH氧化酶如何影响人类和小鼠CF中性粒细胞的抗菌功能。该提案的成功完成将显著增加我们对中性粒细胞如何促进CF病理生物学的理解，并将有助于通过靶向调节CFTR和NADPH氧化酶的Ca+2信号通路来确定新的治疗策略，以控制CF患者的感染和炎症。

 DESCRIPTION (provided by applicant): Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (cftr) gene and characterized by abnormal epithelial ion transport, viscous mucus, chronic bacterial infection, and exaggerated airway inflammation. Opportunistic bacteria that cause lung infection, including Burkholderia cenocepacia (B. cenocepacia), are lethal threat to CF patients. B. cenocepacia is resistant to antibiotics, and host phagocytes fail to clear the infection causing severe inflammation. Neutrophils play essential roles in controlling lung infection and inflammation, however in CF patients; neutrophils cannot eradicate bacteria and promote inflammation. CFTR is a chloride ion channel known to regulate epithelial fluid transport in the lung. The function of CFTR in phagocytes, and how CFTR deficiency affects the inflammatory activities of phagocytic cells is unknown. CFTR mutation has demonstrated to alter directly calcium (Ca2+) homeostasis in airway epithelia, but the impact of this mutation on neutrophil Ca2+-dependent functions remains to be determined. In CF neutrophils, we have found that Ca2+ signaling along with the Ca2+ channel TRPM2 are increased, whereas the production of reactive oxygen species (ROS), and NETosis are deficient. Hence, we hypothesize that CFTR mutation results in increased cytosolic release of Ca2+. Altered Ca2+ homeostasis in turn, positively regulates Ca2+-dependent inflammatory neutrophil functions, but down regulates NADPH activity contributing to neutrophil defective bacterial killing. To test this hypothesis we will: 1). Determine how CFTR mutation impacts calcium signaling pathways in neutrophils 2). Define how the axis TRPM2/NADPH oxidase affects antimicrobial functions of human and mouse CF neutrophils. The successful completion of this proposal will significantly increase our understanding of how neutrophils contribute to CF pathobiology, and will help define novel therapeutic strategies by targeting Ca+2 signaling pathways that modulate CFTR and NADPH oxidase to control infection and inflammation in CF patients.