Hepatocyte growth factor inhibits amiloride-sensitive Na+ channel function in cystic fibrosis airway epithelium in vitro
Hepatocyte growth factor inhibits amiloride-sensitive Na+ channel function in cystic fibrosis airway epithelium in vitro
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DOI：
10.1006/pupt.1999.9999
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发表时间：
1999-01-01
影响因子：
3.2
通讯作者：
Mrsny, RJ
中科院分区：
文献类型：
--
作者：
Shen, BQ;Widdicombe, JH;Mrsny, RJ
囊性纤维化（CF）气道上皮细胞具有降低的cAMP依赖性Cl-传导通道（CFTR）功能，但阿米洛利敏感性Na+通道（ENaC）活性水平增加。最近，ENaC蛋白复合物的α-亚基的表达被证明通过细胞外信号调节蛋白激酶（ERK）途径的激活而下调。在本研究中，我们研究了ERK途径的有效调节剂重组人肝细胞生长因子（rhHGF）对CF气道细胞和SV 40转化的CF鼻上皮细胞系（JME CF/15）的原代培养物的汇合，极化单层ENaC功能的作用。用100 ng/ml及以上浓度的rhHGF处理JME/CF 15细胞，发现显著降低阿米洛利敏感的Na+转运活性。这种效应需要基底侧暴露的细胞因子。在JME/CF 15细胞中加入100 ng/ml rhHGF可降低I-eq，t（1/2）约为18 h，36 h时最大抑制率约为90%。48小时，刺激与rhHGF诱导下调其受体，c-met，在这些细胞中表达。去除rhHGF后，JME/CF 15单层的I-eq降低不会立即逆转。用rhHGF处理似乎不影响单层电阻，也不影响由介质如异丙肾上腺素、组胺或缓激肽诱导的Cl-电流。CF气道细胞片原代培养物的研究表明，rhHGF添加后，阿米洛利敏感电流抑制的敏感性和时程特性相当。这些观察结果与细胞外信号分子（如细胞因子HGF）可能用于降低CF气道细胞中观察到的阿米洛利敏感性Na+离子通道的异常高活性一致。(C)北京：科学出版社.
Cystic fibrosis (CF) airway epithelial cells have a reduced cAMP-dependent Cl- conductance channel (CFTR) function but an increased level of amiloride-sensitive Na+ channel (ENaC) activity. Recently, expression of the alpha-subunit of the ENaC protein complex was shown to be down-regulated by activation of the extracellular signal-regulated protein kinase (ERK) pathway. In the present study we have examined the actions of a potent regulator of the ERK pathway, recombinant human hepatocyte growth factor (rhHGF), on the function of ENaC in confluent, polarized monolayers of both primary cultures of CF airway cells and an SV40-transformed CF nasal epithelial cell line (JME CF/15). Treatment of JME/CF 15 cells with rhHGF at concentrations of 100 ng/ml and above was found to dramatically decrease the activity of amiloride-sensitive Na+ transport. This effect required basolateral exposure of the cytokine. Addition of 100 ng/ml rhHGF to JME/CF 15 cells decreased I-eq with a t(1/2) of similar to 18 h, with a maximal inhibition of similar to 90% by 36 h. By 48 h, stimulation with rhHGF induced a down-regulation of its receptor, c-met, expressed in these cells. The decrease in I-eq of JME/CF 15 monolayers was not immediately reversed upon removal of rhHGF. Treatment with rhHGF did not appear to affect monolayer resistances nor Cl- currents induced by mediators such as isoproterenol, histamine or bradykinin. Studies with primary cultures of CF airway cell sheets demonstrated comparable sensitivity and time-course properties for the inhibition of amiloride-sensitive currents following rhHGF addition. These observations are consistent with the possible application of an extracellular signalling molecule, such as the cytokine HGF, to reduce the abnormally high activity of amiloride-sensitive Na+ ion channels observed in CF airway cells. (C) 1999 Academic Press.