ATP release triggered by activation of the Ca2+-activated K+ channel in human airway Calu-3 cells
ATP release triggered by activation of the Ca2+-activated K+ channel in human airway Calu-3 cells
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DOI：
10.1165/rcmb.2003-0184oc
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发表时间：
2004-03-01
影响因子：
6.4
通讯作者：
Kume, H
中科院分区：
文献类型：
--
作者：
Ito, Y;Son, M;Kume, H
气道粘膜纤毛清除受气道上皮细胞释放的细胞外核苷酸的自分泌/旁分泌调节。本研究旨在寻找生理条件下极化的人气道上皮细胞（Calu-3）中ATP释放的有效调节剂。无论是异丙肾上腺素，毛喉素，也不离子霉素增强细胞外ATP释放荧光素酶检测。然而，1-乙基-2-苯并咪唑啉酮（1-EBIO，1 mM）和氯唑沙宗（CZ，1 mM）直接激活人中间电导，Ca 2+激活的K+通道（hIK-1）主要在顶端室增加ATP释放。fluo-3信号的测量显示，I-EBIO和CZ刺激的胞浆Ca 2+动员被MRS-2179（一种特异性P2 Y（1）受体拮抗剂）抑制。hlK-1介导的ATP释放被hlk-1阻断剂（Charybdotoxin）和Na+-K+-2Cl（-）共转运阻断剂（布美他尼）抑制，而不被GdCl 3（牵张激活的非选择性阳离子（SA）通道的抑制剂）或格列本脲（囊性纤维化跨膜传导调节因子（CFTR）的阻断剂）中断。这些结果表明，通过hlk-1介导的KCl损失导致的细胞体积减小以及通过Nal（+）-K+-2Cl（-）转运蛋白诱导的调节体积增加可能触发ATP的释放，这通过与CFTR和SA通道无关的机制引起P2 Y（1）介导的Ca 2+动员。
Airway mucociliary clearance is subject to the autocrine/paracrine regulation of extracellular nucleotides released from the airway epithelial cells. The present study was performed in pursuit of effective modulators of ATP release under physiologic conditions in polarized human airway epithelial cells (Calu-3). Neither isoproterenol, forskolin, nor ionomycin augmented extracellular ATP release detected by luciferase assay. However, direct activation of the human intermediate conductance, Ca2+-activated K+ channel (hlK-1) by 1-ethyl-2-benzimdazolinone (1-EBIO, 1 mM) and chlorzoxazone (CZ, 1 mM) increased ATP release predominantly in the apical compartment. Measurement of fluo-3 signals revealed that I-EBIO-and CZ-stimulated cytosolic Ca2+ mobilization was suppressed by the presence of MRS-2179, a specific P2Y(1) receptor antagonist. The hlK-1-mediated ATP release was inhibited by a hlk-1 blocker (charybdotoxin), and an Na+-K+-2CI(-) cotransport blocker (bumetanide) without interruption by GdCl3, an inhibitor of stretch-activated nonselective cation (SA) channels, or glybenclamide, a blocker of the cystic fibrosis transmembrane conductance regulator (CFTR). These results suggest that a cell volume decrease via the hlk-1-mediated KCl loss and the resultant induction of a regulatory volume increase via the Nal(+)-K+-2Cl(-) transporter may trigger release of ATP, which causes P2Y(1)-mediated Ca2+ mobilization, through mechanisms unrelated to the CFTR and SA channels.