Airway epithelical Cl channel regulation by iNOS gene

越来越多的证据表明，一氧化氮（NO）在气道中合成和释放，从而在气道的多种功能中发挥作用。在本实验中，为了确定上皮来源的NO是否参与调节Cl分泌，从而调节水分泌到气道管腔，我们在体外研究了分离的人支气管上皮细胞。膜片钳对离体气道上皮的研究表明，细胞内添加高钙溶液加慢激肽，或NO供体s -硝基乙酰-n -青霉胺和硝普塞可增加Cl选择电流和腔内Cl通道打开概率。这种效应伴随着NO选择电流的相应增加，通过使用NO选择电极的极谱测量，并诱导组成型NO合成酶（cNOS）样免疫反应的存在。另一方面，大肠杆菌内毒素、白细胞介素-1β、肿瘤坏死因子-α或干扰素-γ刺激细胞均增加了Cl电导和单Cl通道电流。这种影响同样伴随着培养基中NO浓度的增加，但根据northern分析和免疫细胞化学，这些刺激上调了iNOS mRNA和iNOS蛋白的表达。此外，这些作用被14元大环内酯和糖皮质激素剂量依赖性地抑制。因此，大环内酯类药物和类固醇可能是治疗炎症气道高分泌的潜在治疗方法。

There is increasing evidence that nitric oxide (NO) is synthesized and released in the airways, thereby playing a role in a variety of airway functions. In the present experiment, to determine whether epithelium-derived NO is involved in the regulation of Cl secretion and, hence, water secretion into the airway lumen, we studied isolated human bronchial epithelial cells in vitro. Patch clamp studies of isolated airway epithelium showed that intracellular adition of high calcium solution plus bradykinin, or the NO donors S-nitroacetyl-N-penicillamine and nitroprusside caused an increase in Cl-selective current and open probability of luminal Cl channel. This effect was accompanied by the corresponding increase in NO-selective electrical current, as measured by a polarography using an NO-selective electrode, and induction of the presence of constitutive NO synthase (cNOS)-like immunoreactivities. On the other hand, stimulation of the cells with endotoxin from E. coli, interleukin-1β, tumor necrosis factor-α, or interferon-γ each increased Cl conductance and single Cl channel current. This effect was likewise accompanied by the increase in NO concentration in the medium, but, based on Nothern analysis and immunocytochemistry, expressions of iNOS mRNA and iNOS protein were upregulated by these stimuli. Futhermore,these effects were dose-dependently inhibited by 14-membered macrolides and glucocorticosteroids. Therefore, macrolides and steroids may be therapeutic potential for the treatment of airway hypersecretion in the inflamed airways.