Most basal I(SC) in Calu-3 human airway cells is bicarbonate-dependent Cl- secretion.
Most basal I(SC) in Calu-3 human airway cells is bicarbonate-dependent Cl- secretion.
复制标题
Calu-3 人气道细胞中的大多数基础 I(SC) 是碳酸氢盐依赖性 Cl- 分泌。
作者：
M. Singh;M. Krouse;S. Moon;J. Wine
浆液细胞分泌富含抗生素的液体，但囊性纤维化患者分泌受损。我们正在研究Calu-3细胞作为浆液细胞模型。在空气界面生长的Calu-3细胞的基础短路电流（I[SC]）大约是水下培养的6倍（69 +/- 22 vs 11 +/- 10 microA/cm2）。在这两种条件下，布美他胺对基础I（SC）的还原率均仅为7 +/- 5%，而顶端酰胺、4,4'-二异硫氰二苯乙烯-2,2'-二磺酸、4,4'-二硝基二苯乙烯-2,2'-二磺酸（DNDS）或杯芳烃对SC的还原率均无影响，但n -苯基氨基苯甲酸对SC的还原率为77 +/- 18%。三种运输机制几乎占了所有的基础I（SC）。最大的成分是HCO3（-）依赖性Cl-分泌。用n -2-羟乙基哌啶- n '-2-乙磺酸缓冲溶液替代Krebs-Henseleit溶液，并将气体从95% O2-5% CO2改为空气，可使基础I（SC）降低61 +/- 10%。乙酰唑胺可降低基底I(SC) 33% +/- 6%，而乙酰唑胺+基底外侧DNDS可消除42-58%的布美他尼不敏感基底I（SC）。DNDS和乙酰唑胺在无HCO3（-）溶液中均无效果。根尖根际素是一种Na+-葡萄糖共运输的阻断剂，消除了剩余I（SC）的一半。用葡萄糖酸盐代替Cl消除了除苯酞敏感成分外的所有I（SC）。与基础I（SC）不同，80 +/- 24%的刺激I（SC）被布美他尼抑制。因此，基础分泌和刺激分泌是由不同的机制介导的。
Serous cells secrete antibiotic-rich fluid, but secretion is impaired in cystic fibrosis. We are investigating Calu-3 cells as a serous cell model. Basal short-circuit current (I[SC]) in Calu-3 cells grown at air interface had a basal I(SC) approximately six times larger than submerged cultures (69 +/- 22 vs. 11 +/- 10 microA/cm2). Basal I(SC) in either condition was reduced only 7 +/- 5% by bumetanide and was unaffected by apical amiloride, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS), or calixarene but was reduced 77 +/- 18% by N-phenylanthranilic acid. Three transport mechanisms accounted for almost all basal I(SC). The largest component is HCO3(-)-dependent Cl- secretion. Replacement of Krebs-Henseleit solution with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered solution and changing gassing from 95% O2-5% CO2 to air reduced the basal I(SC) by 61 +/- 10%. Acetazolamide decreased basal I(SC) by 33 +/- 6%, whereas acetazolamide + basolateral DNDS eliminated 42-58% of the bumetanide-insensitive basal I(SC). Neither DNDS nor acetazolamide had any effect when applied in HCO3(-)-free solution. Apical phlorizin, a blocker of Na+-glucose cotransport, eliminated one-half of the remaining I(SC). Cl- replacement with gluconate eliminated all I(SC) except the phlorizin-sensitive component. Unlike basal I(SC), 80 +/- 24% of stimulated I(SC) was inhibited by bumetanide. Thus basal and stimulated secretions are mediated by different mechanisms.