S-Nitrosothiol Breakdown by Airway Epithelial Cells

描述（由申请人提供）：S-亚硝基硫醇是一氧化氮和半胱氨酸硫醇的内源性加合物。 越来越多地认识到，S-亚硝基化反应可能导致翻译后蛋白质修饰。 这些修饰与可能被调节至生理优势的环GMP-独立的生物活性相关。 例如，蛋白质可以通过与S-亚硝基化肽如S-亚硝基谷胱甘肽的转亚硝化反应来修饰，其浓度似乎是酶促调节的。 事实上，现在有几种酶被认为可以调节S-亚硝基谷胱甘肽的催化活性，包括谷胱甘肽依赖性甲醛脱氢酶和γ-谷氨酰转肽酶。 S-亚硝基硫醇生物化学可能参与气道中广谱生物活性的调节，包括离子通道传导性、炎性细胞凋亡和气道平滑肌松弛。 值得注意的是，我们最近观察到S-亚硝基谷胱甘肽增加了囊性纤维化跨膜调节蛋白（CFTR）最常见的突变形式deltaF 508的表达和成熟。 在囊性纤维化和哮喘患者的气道中，S-亚硝基硫醇的水平似乎较低，部分原因是S-亚硝基谷胱甘肽分解代谢酶的活性增加。 事实上，如果不是S-亚硝基谷胱甘肽催化剂的加速作用，S-亚硝基谷胱甘肽替代疗法可以被设想为囊性纤维化和哮喘的新疗法。 在本项目中，我们计划1）表征S-亚硝基谷胱甘肽催化剂在囊性纤维化和哮喘气道上皮中的调节; 2）确定S-亚硝基谷胱甘肽和其他S-亚硝基硫醇可增加kF 508 CFTR成熟的机制; 3）评估S-亚硝基谷胱甘肽催化剂可能被规避以在气道中实现有益生物活性的机制，包括增加CFTR成熟。 我们预计，该项目将为理解囊性纤维化和哮喘的细胞生物学提供新的工具，并可能导致这两种疾病的新疗法的开发。

DESCRIPTION (provided by applicant): S-Nitrosothiols are endogenous adducts of nitric oxide and cysteine thiols. Increasingly, it is appreciated that S-nitrosylation reactions may result in post-translational protein modifications. These modifications have been associated with cyclic GMP-independent bioactivities that may be regulated to physiological advantage. For example, proteins may be modified by transnitrosation reactions with S-nitrosylated peptides such as S-nitrosoglutathione, concentrations of which appear to be enzymatically regulated. Indeed, several enzymes are now appreciated to regulate the catabolism of S-nitrosoglutathione, including glutathione-dependent formaldehyde dehydrogenase and gamma-glutamyl transpeptidase. S-nitrosothiol biochemistry may be involved in the regulation of a broad spectrum of bioactivities in the airway, including ion channel conductivity, inflammatory cell apoptosis, and airway smooth muscle relaxation. Of note, we have recently observed that S-nitrosoglutathione increases the expression and maturation of the most common mutant form of cystic fibrosis transmembrane regulatory protein (CFTR), deltaF508. Levels of S-nitrosothiols appear to be low in the airways of patients with both cystic fibrosis and with asthma, in part because of increased activity of S-nitrosoglutathione catabolic enzymes. Indeed, if it was not for accelerated S-nitrosoglutathione catabolism, S-nitrosoglutathione replacement therapy could be envisioned as a novel therapy for both cystic fibrosis and asthma. In this project, we plan to 1) characterize the regulation of S-nitrosothiol catabolism in the cystic fibrosis and asthmatic airway epithelium; 2) define the mechanism by which S-nitrosoglutathione and other S-nitrosothiols may increase the maturation of kF508 CFTR; and 3) evaluate mechanisms by which S-nitrosoglutathione catabolism might be circumvented to achieve salutary bioactivities in the airways, including increased CFTR maturation. We anticipate that this project will provide new tools for understanding the cell biology of cystic fibrosis and asthma, and that it may lead to the development of new therapies for both diseases.