Ruth and Bruce Rappaport Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Sciences, TechnionIsrael Institute of Technology, Haifa, Israel.
Ann N Y Acad Sci. 2010 Feb;1188:68-77. doi: 10.1111/j.1749-6632.2009.05085.x.
Because previous findings showed that in human embryonic stem cell-derived cardiomyocytes (hESC-CM) the machinery for Ca2+-induced release of calcium is immature, we tested the hypothesis that hESC-CM contain functional 1,4,5-inositol triphosphate (IP3)-operated intracellular Ca2+ ([Ca2+]i) stores. We investigated the effects of angiotensin II (AT-II) and endothelin 1 (ET-1), which activate the 1,4,5-IP3 pathway, on [Ca2+]i transients and contractions in hESC-CM. Our major findings were that in hESC-CM, both AT-II (10(-9)-10(-7) M) and ET-1 (10(-9)-10(-7) M) exert inotropic and lusitropic effects. The involvement of 1,4,5-IP3-dependent intracellular Ca2+ release in AT-I-induced effects was supported by these findings: the effects of AT-II were blocked by 2-aminoethoxyphenyl borate (2-APB, a 1,4,5-IP3 receptor blocker) and U73122 (a phosopholipase C blocker); and hESC-CM express AT-II type 1 and IP3 type I and II receptors as determined by fluorescence immunostaining. In conclusion, hESC-CM exhibit functional AT-II and ET-1 signaling pathways, as well as 1,4,5-IP3-operated releasable Ca2+ stores.
由于先前的研究结果表明，在人类胚胎干细胞衍生的心肌细胞（hESC-CM）中，钙诱导钙释放的机制尚未成熟，因此我们测试了以下假设：hESC-CM 中含有功能性的 1,4,5-三磷酸肌醇（IP3）操作的细胞内 Ca2+（[Ca2+]i）库。我们研究了血管紧张素 II（AT-II）和内皮素 1（ET-1）的作用，这两种物质激活 1,4,5-IP3 途径，对 hESC-CM 的 [Ca2+]i 瞬变和收缩产生影响。我们的主要发现是，在 hESC-CM 中，AT-II（10(-9)-10(-7) M）和 ET-1（10(-9)-10(-7) M）均具有正性肌力和正性松弛作用。AT-I 诱导作用中涉及 1,4,5-IP3 依赖性细胞内 Ca2+释放的发现支持了这一观点：AT-II 的作用被 2-氨基乙氧基苯硼酸（2-APB，1,4,5-IP3 受体阻滞剂）和 U73122（一种磷脂酶 C 阻滞剂）阻断；荧光免疫染色表明 hESC-CM 表达 AT-II 型 1 和 IP3 型 1 和 2 受体。总之，hESC-CM 表现出功能性的 AT-II 和 ET-1 信号通路，以及 1,4,5-IP3 操作的可释放 Ca2+库。
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