Protease-activated receptor-1 stimulates Ca2+-dependent Cl- secretion in human intestinal epithelial cells
Protease-activated receptor-1 stimulates Ca2+-dependent Cl- secretion in human intestinal epithelial cells
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DOI：
10.1152/ajpgi.2001.281.2.g323
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发表时间：
2001-08-01
影响因子：
4.5
通讯作者：
MacNaughton, WK
中科院分区：
文献类型：
--
作者：
Buresi, MC;Schleihauf, E;MacNaughton, WK
凝血酶受体蛋白酶激活受体1（PAR-1）在组织中分布广泛，参与多种生理功能。由于炎症期间凝血酶存在于肠腔和粘膜中，因此我们试图确定人肠上皮细胞中 PAR-1 的表达和功能。 RT-PCR 显示 SCBN 细胞（一种非转化的十二指肠上皮细胞系）中 PAR-1 mRNA 的表达。安装在尤斯室中的汇合 SCBN 单层对 PAR-1 的激活作出反应，短路电流随 Cl 的增加而增加。 BaCl2 和 Ca2+-ATPase 抑制剂毒胡萝卜素可阻断分泌作用，但 L 型 Ca2+ 通道阻断剂维拉帕米或 DIDS（Ca2+ 依赖性 Cl- 转运的非选择性抑制剂）不会阻断分泌作用。对凝血酶和 PAR-1 激活肽的反应表现出自身脱敏和交叉脱敏。负载 Fura 2 的 SCBN 细胞在 PAR-1 激活后荧光增加，表明细胞内 Ca2+ 增加。 RT-PCR 显示 SCBN 细胞表达囊性纤维化跨膜电导调节因子 (CFTR) 和低渗激活的 Cl-通道-2 的 mRNA，但不表达 Ca2+ 依赖性 Cl-通道-1 的 mRNA。 PAR-1 激活未能增加细胞内 cAMP，表明 CFTR 通道不参与 Cl- 分泌反应。我们的数据表明 PAR-1 在人肠上皮细胞上表达并调节新的 Ca2+ 依赖性 Cl- 分泌途径。这对于凝血酶水平升高的炎症性肠道疾病可能具有临床意义。
The thrombin receptor, protease-activated receptor-1 (PAR-1), has wide tissue distribution and is involved in many physiological functions. Because thrombin is in the intestinal lumen and mucosa during inflammation, we sought to determine PAR-1 expression and function in human intestinal epithelial cells. RT-PCR showed PAR-1 mRNA expression in SCBN cells, a nontransformed duodenal epithelial cell line. Confluent SCBN monolayers mounted in Ussing chambers responded to PAR-1 activation with a Cl--dependent increase in short-circuit current. The secretory effect was blocked by BaCl2 and the Ca2+-ATPase inhibitor thapsigargin, but not by the L-type Ca2+ channel blocker verapamil or DIDS, the nonselective inhibitor of Ca2+-dependent Cl- transport. Responses to thrombin and PAR-1-activating peptides exhibited auto- and crossdesensitization. Fura 2-loaded SCBN cells had increased fluorescence after PAR-1 activation, indicating increased intracellular Ca2+. RT-PCR showed that SCBN cells expressed mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) and hypotonicity-activated Cl- channel-2 but not for the Ca2+ dependent Cl- channel-1. PAR-1 activation failed to increase intracellular cAMP, suggesting that the CFTR channel is not involved in the Cl- secretory response. Our data demonstrate that PAR-1 is expressed on human intestinal epithelial cells and regulates a novel Ca2+-dependent Cl- secretory pathway. This may be of clinical significance in inflammatory intestinal diseases with elevated thrombin levels.