Ca2+-sensing receptors in intestinal epithelium
Ca2+-sensing receptors in intestinal epithelium
复制标题
DOI：
10.1152/ajpcell.1997.273.4.c1168
复制
发表时间：
1997-10-01
影响因子：
5.5
通讯作者：
Breitwieser, GE
中科院分区：
文献类型：
--
作者：
Gama, L;BaxendaleCox, LM;Breitwieser, GE
用逆转录聚合酶链式反应(RT-PCR)和Northern blotting方法检测了几种人肠上皮细胞系(T84、HT-29和Caco-2)和大鼠肠上皮细胞中钙敏感受体(CAR)的表达。聚合酶链式反应产物的限制性内切酶图谱与人和鼠序列预测的大小一致。CAR激动剂(Ca~(2+)、多聚L-精氨酸、鱼精蛋白)介导了细胞内Ca~(2+)的增加(通过Fura-2荧光的变化来监测)，这依赖于从thapsigargin敏感的存储区释放的钙。磷脂酰肌醇-磷脂酶C抑制剂U-73122可消除CAR激动剂引起的细胞内钙升高，而其失活类似物U-73343则无此作用。百日咳毒素预处理对CAR激动剂介导的细胞内钙调节无影响。综上所述，这些研究表明，CAR在肠上皮细胞中表达，并与细胞内钙离子的动员相结合。肠上皮细胞中CAR的存在为研究细胞外钙离子在调节肠上皮细胞分化和跨上皮钙转运中的作用提供了一个新的研究场所(S)。
Expression of Ca2+-sensing receptors (CaR) was demonstrated in several human intestinal epithelial cell lines (T84, HT-29, and Caco-2) and in rat intestinal epithelium by both reverse transcriptase-polymerase chain reaction (PCR) and Northern blotting of RNA. Restriction patterns of the PCR products were of the sizes predicted by the human and rat sequences. CaR agonists (Ca2+, poly-L-arginine, prot amine) mediated an increase in intracellular Ca2+ in HT-29-18-C1 cells (monitored by changes in fura 2 fluorescence), which was dependent on release from thapsigargin-sensitive stores. U-73122, an inhibitor of phosphatidylinositol-phospholipase C, eliminated the CaR agonist-mediated rise in intracellular Ca2+, whereas its inactive analog, U-73343, had no effect. Pertussis toxin pretreatment had no effect on CaR agonist-mediated modulation of intracellular Ca2+. Taken together, these studies demonstrate that CaR are expressed in intestinal epithelial cells and couple to mobilization of intracellular Ca2+. The presence of CaR in intestinal epithelial cells presents a new locus for investigations into the role(s) of extracellular Ca2+ in modulating intestinal epithelial cell differentiation and transepithelial Ca2+ transport.