School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China.
J Cell Physiol. 2012 Jun;227(6):2519-30. doi: 10.1002/jcp.22990.
Embryonic stem cells (ESCs) can self-renew indefinitely and differentiate into all cell lineages. Calcium is a universal second messenger which regulates a number of cellular pathways. Previous studies showed that store-operated calcium channels (SOCCs) but not voltage-operated calcium channels are present in mouse ESCs (mESCs). In this study, store-operated calcium entry (SOCE) was found to exist in mESCs using confocal microscopy. SOCC blockers lanthanum, 2-aminoethoxydiphenyl borate (2-APB) and SKF-96365 reduced mESC proliferation in a concentration-dependent manner, suggesting that SOCE is important for ESC proliferation. Pluripotent markers, Sox-2, Klf-4, and Nanog, were down-regulated by 2-APB, suggesting that self-renewal property of mESCs relies on SOCE. 17β-estradiol (E2) enhanced mESC proliferation. This enhanced proliferation was associated with an increment of SOCE. Both stimulated proliferation and increased SOCE could be reversed by SOCC blockers suggesting that E2 mediates its stimulatory effect on proliferation via enhancing SOCE. Also, cyclosporin A and INCA-6, inhibitors of calcineurin [phosphatase that de-phosphorylates and activates nuclear factor of activated T-cells (NFAT)], reversed the proliferative effect of E2, indicating that NFAT is involved in E2-stimulated proliferation. Interestingly, E2 caused the nuclear translocation of NFATc4, and this could be reversed by 2-APB. These results suggested that NFATc4 is the downstream target of E2-induced SOCE. The present investigation provides the first line of evidence that SOCE and NFAT are crucial for ESCs to maintain their unique characteristics. In addition, the present investigation also provides novel information on the mechanisms of how E2, an important female sex hormone, affects ESC proliferation.
胚胎干细胞（ESCs）可以无限自我更新并分化为所有细胞谱系。钙是一种普遍的第二信使，调节许多细胞途径。先前的研究表明，储存操作钙通道（SOCCs）而不是电压操作钙通道存在于小鼠胚胎干细胞（mESCs）中。在这项研究中，使用共聚焦显微镜发现 mESCs 中存在储存操作钙内流（SOCE）。SOCC 阻断剂镧、2-氨基乙氧基二苯硼酸盐（2-APB）和 SKF-96365 以浓度依赖的方式减少 mESC 增殖，表明 SOCE 对 ESC 增殖很重要。多能标记物 Sox-2、Klf-4 和 Nanog 被 2-APB 下调，表明 mESC 的自我更新特性依赖于 SOCE。17β-雌二醇（E2）增强了 mESC 的增殖。这种增强的增殖与 SOCE 的增加有关。SOCC 阻断剂可逆转刺激增殖和增加 SOCE，表明 E2 通过增强 SOCE 介导其对增殖的刺激作用。此外，环孢菌素 A 和 INCA-6，钙调神经磷酸酶[磷酸酶，使激活 T 细胞的核因子（NFAT）去磷酸化并激活]的抑制剂，逆转了 E2 的增殖作用，表明 NFAT 参与了 E2 刺激的增殖。有趣的是，E2 导致 NFATc4 的核转位，这可以被 2-APB 逆转。这些结果表明 NFATc4 是 E2 诱导的 SOCE 的下游靶标。本研究首次提供证据表明，SOCE 和 NFAT 对于 ESCs 维持其独特特性至关重要。此外，本研究还提供了有关 E2（一种重要的女性性激素）如何影响 ESC 增殖的机制的新信息。
