Egan M, Flotte T, Afione S, Solow R, Zeitlin P L, Carter B J, Guggino W B
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Nature. 1992 Aug 13;358(6387):581-4. doi: 10.1038/358581a0.
Cystic fibrosis (CF) is a lethal genetic disease resulting in a reduced Cl- permeability, increased mucous sulphation, increased Na+ absorption and defective acidification of lysosomal vesicles. The CF gene encodes a protein (the cystic fibrosis transmembrane conductance regulator, CFTR) that can function as a low-conductance Cl- channel with a linear current-voltage relationship whose regulation is defective in CF patients. Larger conductance, outwardly rectifying Cl- channels are also defective in CF and fail to activate when exposed either to cyclic AMP-dependent protein kinase A or to protein kinase C. The role of the outwardly rectifying Cl- channel in CF has been questioned. We report here that expression of recombinant CF genes using adeno-associated virus vectors in CF bronchial epithelial cells corrects defective Cl- secretion, that it induces the appearance of small, linear conductance Cl- channels, and restores protein kinase A activation of outwardly rectifying Cl- channels. These results re-establish an involvement of outwardly rectifying Cl- channels in CF and suggest that CFTR regulates more than one conductance pathway in airway tissues.
囊性纤维化（CF）是一种致命的遗传性疾病，会导致氯离子通透性降低、黏液硫酸化增加、钠离子吸收增加以及溶酶体囊泡酸化缺陷。CF基因编码一种蛋白质（囊性纤维化跨膜传导调节因子，CFTR），它可作为一种低电导氯离子通道发挥作用，具有线性电流-电压关系，而在CF患者中其调节存在缺陷。更大电导的外向整流氯离子通道在CF中也存在缺陷，并且在暴露于环磷酸腺苷依赖性蛋白激酶A或蛋白激酶C时无法激活。外向整流氯离子通道在CF中的作用一直受到质疑。我们在此报告，使用腺相关病毒载体在CF支气管上皮细胞中表达重组CF基因可纠正缺陷性氯离子分泌，诱导出现小的、线性电导的氯离子通道，并恢复蛋白激酶A对外向整流氯离子通道的激活。这些结果重新确立了外向整流氯离子通道与CF的关联，并表明CFTR在气道组织中调节不止一种电导途径。
