Mechanism of glibenclamide inhibition of cystic fibrosis transmembrane conductance regulator Cl- channels expressed in a murine cell line
Mechanism of glibenclamide inhibition of cystic fibrosis transmembrane conductance regulator Cl- channels expressed in a murine cell line
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DOI：
10.1111/j.1469-7793.1997.333bh.x
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发表时间：
1997-09-01
影响因子：
5.5
通讯作者：
Robinson, KA
中科院分区：
文献类型：
--
作者：
Sheppard, DN;Robinson, KA
1.磺脲类药物格列本脲是一种广泛使用的囊性纤维化跨膜传导调节因子（CFTR）抑制剂。为了研究格列本脲如何抑制CFTR，我们使用从表达野生型人CFTR的细胞中切除的由内而外的膜贴片研究了CFTR Cl-通道。向细胞内溶液中加入格列本脲（10-100 μ M），导致CFTR Cl-通道开放时间呈浓度依赖性减少，但关闭时间没有变化。这表明格列本脲是CFTR的开放通道阻滞剂。3.格列本脲是一种弱有机酸。细胞内溶液的酸化缓解了格列本脲对CFTR的抑制，表明格列本脲的阴离子形式抑制CFTR。为了开始鉴定CFTR中的格列本脲结合位点，我们研究了格列本脲是否与MgATP或Cl-离子竞争共同结合位点。格列本脲对CFTR的抑制不受CFTR的核苷酸依赖性刺激的影响，表明格列本脲和细胞内MgATP在不同位点与CFTR相互作用。格列本脲对CFTR的抑制是电压依赖性的，当外部Cl-浓度降低时，抑制作用增强。数据表明，格列本脲和Cl-离子可能竞争位于CFTR孔的一部分的大细胞内前庭内的共同结合位点。
1. The sulphonylurea drug glibenclamide is a widely used inhibitor of the cystic fibrosis transmembrane conductance regulator (CFTR). To investigate how glibenclamide inhibits CFTR, we studied CFTR Cl- channels using excised inside-out membrane patches from cells expressing wild-type human CFTR.2. Addition of glibenclamide (10-100 mu M) to the intracellular solution caused a concentration-dependent decrease in the open time of CFTR Cl- channels, but closed times did not change. This suggests that glibenclamide is an open-channel blocker of CFTR.3. Glibenclamide is a weak organic acid. Acidification of the intracellular solution relieved glibenclamide inhibition of CFTR, suggesting that the anionic form of glibenclamide inhibits CFTR.4. To begin to identify the glibenclamide binding site in CFTR, we investigated whether glibenclamide competes with either MgATP or Cl- ions for a common binding site. Glibenclamide inhibition of CFTR was unaffected by nucleotide-dependent stimulation of CFTR, suggesting that glibenclamide and intracellular MgATP interact with CFTR at distinct sites.5. Glibenclamide inhibition of CFTR was voltage dependent and enhanced when the external Cl- concentration was decreased. The data suggest that glibenclamide and Cl- ions may compete for a common binding site located within a large intracellular vestibule that is part of the CFTR pore.