BIOLOGY OF NITRIC OXIDE DERIVED FROM AIRWAY EPITHELIUM

呼吸道上皮分泌松弛因子(S)，这可能是重要的 控制呼吸道张力。这些物种的化学鉴定还没有 被很好地刻画出来了。一氧化氮是一种强大的平滑肌松弛剂 牵涉到血压和胃肠的调节 能动性。然而，药理学文献阐述其在 作为一种来自上皮细胞的松弛因子， 尤其是，是有争议的。此外，一个人面临着一个重大的 肺中的悖论，即NO的生物活性需要 与其在富氧环境中已有的毒性相一致。 我们提出，悖论的答案在于NO的氧化还原化学， 特别是它与氨基酸和蛋白质形成加合物的能力 硫醇。这些S-亚硫醇(RSNO)是耐氧反应的 并具有平滑肌松弛活性。的中心假说 这一建议是，上皮细胞是一氧化氮的丰富来源， 与硫醇基团的反应在其细胞内起着关键作用 生物化学和呼吸道药理学。 该项目的具体目标是： 1)进行免疫组织化学、生化和分子生物学研究 呼吸道上皮型一氧化氮合酶特性研究(S)； 2)对内源氮氧化物进行鉴定和化学表征 呼吸道上皮细胞合成的RSNO种类； 3)确定RSNO形成和代谢的生化途径。 呼吸道上皮细胞；以及 4)测定上皮源性NO和RSNO对呼吸道的影响 在选定的动物模型、正常人类呼吸道和状态下的功能 呼吸道高反应性。 通过证明一氧化氮在呼吸道上皮细胞中的生理重要性， 上皮细胞中形成的加合物的化学特征和 分泌到他们的环境中，并定义了支气管扩张剂的活性 内源性NO物种，我们希望确定新的药理作用 以呼吸道为特征的疾病的治疗方法 高反应性。

The airway epithelium secretes relaxing factor(s) that may be important in control of airway tone. The chemical identify of these species has not been well characterized. Nitric oxide is a powerful smooth muscle relaxant implicated in the regulation of blood pressure and gastrointestinal motility. However, the pharmacological literature addressing its role in the airways in general, and as a relaxing factor derived from epithelium, in particular, is controversial. Moreover, one is faced with a major paradox in the lung, namely, that the biological activity of NO needs to be reconciled with its established toxicity in an oxygen-rich environment. We have proposed that answers to paradox lie in the redox chemistry of NO, specifically its capacity to form adducts with both amino acid and protein thiols. These S-nitrosothiols (RSNO) are resistant to reaction with oxygen and possess smooth muscle relaxant activity. The central hypothesis of this proposal is that the epithelium is a rich source of NO, and that reactions with thiol groups play a critical role in its cellular biochemistry and airway pharmacology. The Specific Aims of this project are: 1) to undertake the immunohistochemical, biochemical and molecular characterization of the airway epithelial NO synthase(s); 2) to identity and chemically characterize the endogenous nitrogen oxides and RSNO species synthesized by airway epithelium; 3) to define the biochemical pathways of RSNO formation and metabolism in airway epithelial cells; and 4) to determine the effects of epithelial-derived NO and RSNO on airway function in selected animal models, normal human airways and states of airway hyperreactivity. By demonstrating the physiological importance of NO in airway epithelium, chemically characterizing the adducts formed in epithelial cells and secreted into their environment and defining the bronchodilator activities of endogenous NO species, we expect to identify novel pharmacological approaches for treatment of diseases characterized by airway hyperreactivity.