Expression of the chloride channel ClC-2 in the murine small intestine epithelium
Expression of the chloride channel ClC-2 in the murine small intestine epithelium
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DOI：
10.1152/ajpcell.2000.279.6.c1787
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发表时间：
2000-12-01
影响因子：
5.5
通讯作者：
Bear, CE
中科院分区：
文献类型：
--
作者：
Gyömörey, K;Yeger, H;Bear, CE
氯离子通道 ClC-2 与新生儿气道氯离子分泌有关。为了评估其在小肠分泌中的作用，我们评估了其在小鼠回肠段中的亚细胞表达，并研究了该组织的氯离子转运特性。在尤斯室中以负短路电流（I-sc）评估小鼠回肠段粘膜上的氯离子分泌。如果 ClC-2 有助于氯离子分泌，我们根据之前的研究预测，粘膜浴稀释会刺激负 I-sc，并且这种反应将取决于氯离子，并且会被氯离子通道阻滞剂 5-硝基-2-(3-苯基丙氨基)苯甲酸阻断，但不会被 DIDS 阻断。事实上，粘膜低渗性确实刺激了 I-sc 的氯化物依赖性变化，其药理学特性与 ClC-2 一致。这种分泌反应不太可能是由囊性纤维化跨膜电导调节器（CFTR）通道介导的，因为它也在 CFTR 敲除动物中观察到。通过共聚焦和电子显微镜对小鼠肠上皮细胞中 ClC-2 蛋白的天然表达模式进行评估表明，ClC-2 表现出一种新的分布，这种分布模式对于参与氯离子分泌的通道来说有些出乎意料。免疫标记的 ClC-2 主要在相邻肠上皮细胞之间的紧密连接复合物中检测到。
The chloride channel ClC-2 has been implicated in neonatal airway chloride secretion. To assess its role in secretion by the small intestine, we assessed its subcellular expression in ileal segments obtained from mice and studied the chloride transport properties of this tissue. Chloride secretion across the mucosa of murine ileal segments was assessed in Ussing chambers as negative short-circuit current (I-sc). If ClC-2 contributed to chloride secretion, we predicted on the basis of previous studies that negative I-sc would be stimulated by dilution of the mucosal bath and that this response would depend on chloride ion and would be blocked by the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid but not by DIDS. In fact, mucosal hypotonicity did stimulate a chloride-dependent change in I-sc that exhibited pharmacological properties consistent with those of ClC-2. This secretory response is unlikely to be mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) channel because it was also observed in CFTR knockout animals. Assessment of the native expression pattern of ClC-2 protein in the murine intestinal epithelium by confocal and electron microscopy showed that ClC-2 exhibits a novel distribution, a distribution pattern somewhat unexpected for a channel involved in chloride secretion. Immunolabeled ClC-2 was detected predominantly at the tight junction complex between adjacent intestinal epithelial cells.