S-NITROSOTHIOL BREAKDOWN BY AIRWAY EPITHELIAL CELLS

S-亚硝基硫醇被气道上皮细胞分解

• 批准号: 6343600
• 负责人: Benjamin Gaston
• 金额: $ 19.57万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6343600
• 关键词: acivicin; asthma; bronchodilators; bronchospasm; dexamethasone; glutathione; gold thioglucose; guinea pigs; hemoglobin; interleukin 4; nitric oxide; nitric oxide synthase; nitrogen metabolism; nitroso compounds; oxidative stress; respiratory epithelium; thiols; tissue /cell culture; vasoactive intestinal peptide

S-Nitrosothiols (SNOs) in general - and S-nitrosoglutathione (GSNO) in particular - are stable, potent bronchodilators which also have immune regulatory functions and are present in the normal human airway. Asthmatic bronchospasm is associated with paradoxically low airway SNO levels - and undetectable GSNO levels - despite relatively high concentrations of nitric oxide ( NO) in expired air and upregulation of inducible-nitric oxide synthase. This paradox may be best explained by considering GSNO to be a reservoir of bioactive nitrogen oxides in the airway - as it is in brain and other tissues - the breakdown of which is accelerated in asthma. In this sense, airway SNO catabolism may contribute both to high expired NO concentrations and to bronchospasm in asthmatic patients. This project will test the hypotheses that 1) airway epithelial cells catabolize SNO; 2) the SNO catabolic activity of airway epithelial cells is altered by stimulants relevant to asthma pathophysiology; and 3) airway epithelial cell-mediated SNO catabolism inhibits airway smooth muscle relaxation. A new methodology will be used to study the conversion of SNO to NO in the presence of airway cells. Preliminary data using this system suggest that there are epithelial cell proteins which catalyze GSNO breakdown. These proteins will be characterized with regard to size, sequence, reactant and product stoichiometry and kinetics. Further, the effects of interleukin 4, vasoactive intestinal peptide, dexamethasone, acivicin, aurothioglucose and hemoglobin on epithelial GSNO catabolism and nitrogen oxide transport will be investigated. Finally, the relevance of epithelial GSNO breakdown will be studied in a bioassay of guinea-pig airway smooth muscle relaxation. In summary, this project will test the overall hypothesis that GSNO-mediated relaxation of airway smooth muscle is inhibited in the presence of airway epithelial cells by a regulated protein which catalyzes GSNO catabolism. If this hypothesis is proven, prevention of GSNO catabolism may define new asthma therapies.

一般 S-亚硝基硫醇 (SNO) - 以及 S-亚硝基谷胱甘肽 (GSNO) 特别是 - 是稳定、有效的支气管扩张剂，也具有免疫功能 调节功能并存在于正常人体气道中。 哮喘性支气管痉挛与反常的低气道 SNO 相关 水平 - 以及无法检测到的 GSNO 水平 - 尽管相对较高 呼出气中一氧化氮 (NO) 浓度和上调 诱导型一氧化氮合酶。 这个悖论可以最好地解释为 考虑到 GSNO 是生物活性氮氧化物的储存库 气道 - 就像在大脑和其他组织中一样 - 其破裂 哮喘时会加速。 从这个意义上说，气道 SNO 分解代谢可能 导致高呼出一氧化氮浓度和支气管痉挛 在哮喘患者中。 该项目将测试以下假设：1) 气道上皮细胞分解代谢 SNO； 2) SNO分解代谢活性 气道上皮细胞的数量被与哮喘相关的兴奋剂改变 病理生理学； 3) 气道上皮细胞介导的 SNO 分解代谢 抑制气道平滑肌松弛。 一种新的方法论将是 用于研究在气道存在的情况下 SNO 转化为 NO 细胞。 使用该系统的初步数据表明， 催化 GSNO 分解的上皮细胞蛋白。 这些蛋白质 将在尺寸、顺序、反应物和 产品化学计量和动力学。 此外，白细胞介素的作用 4、血管活性肠肽、地塞米松、阿西维星、 金硫葡萄糖和血红蛋白对上皮 GSNO 分解代谢的影响 将研究氮氧化物的传输。 最后，相关性 将通过豚鼠生物测定研究上皮 GSNO 分解的情况 气道平滑肌松弛。 总而言之，该项目将测试 总体假设 GSNO 介导的气道平滑肌松弛 在气道上皮细胞存在的情况下受到调节的抑制 催化 GSNO 分解代谢的蛋白质。 如果这个假设被证明， 预防 GSNO 分解代谢可能会定义新的哮喘治疗方法。