Store-operated Ca(2+) entry is not required for fertilization-induced Ca(2+) signaling in mouse eggs.
Store-operated Ca(2+) entry is not required for fertilization-induced Ca(2+) signaling in mouse eggs.
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DOI：
10.1016/j.ceca.2017.02.004
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发表时间：
2017-07
期刊：
影响因子：
4
通讯作者：
Williams CJ
中科院分区：
文献类型：
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作者：
Bernhardt ML;Padilla-Banks E;Stein P;Zhang Y;Williams CJ
由于内质网（ER）周期性释放Ca 2+，导致细胞质Ca 2+的重复振荡驱动哺乳动物受精后的胚胎发育。持续的Ca 2+振荡需要细胞外Ca 2+内流来支持ER储存的重新填充，但这种Ca 2+内流的机制存在争议。尽管钙池操纵的钙离子进入（SOCE）是一种有吸引力的候选机制，但几个研究小组就卵母细胞和卵子中SOCE的重要性得出了相互矛盾的结论。为了明确解决这个问题，在缺乏SOCE的主要成分、ER Ca 2+传感器STIM蛋白和质膜Ca 2+通道ORAI 1的卵母细胞和卵中评估Ca 2+内流。我们产生了刺激1和刺激2的卵母细胞特异性条件性敲除（cKO）小鼠，还产生了刺激1/2双cKO小鼠。缺乏一个或两个STIM蛋白的女性是肥沃的，他们的排卵卵显示正常模式的Ca 2+振荡受精后。此外，没有观察到损害ER Ca 2+商店或Ca 2+流入后商店耗尽。对来自全球缺乏ORAI 1的小鼠的卵进行了类似的研究;未观察到异常。此外，自发Ca 2+内流是正常的卵母细胞从刺激1/2 cKO和ORAI 1-null小鼠。最后，我们测试了TRPM 7样通道是否可以支持自发性Ca 2+内流，并发现它在很大程度上被TRPM 7特异性抑制剂NS 8593阻止。受精诱导的Ca 2+振荡也受到NS 8593的损害。结合起来，这些数据有力地表明，SOCE是不需要支持适当的Ca 2+信号在小鼠卵母细胞和卵子，TRPM 7样通道可能有助于Ca 2+流入，这是以前归因于SOCE。
Repetitive oscillations in cytoplasmic Ca2+ due to periodic Ca2+ release from the endoplasmic reticulum (ER) drive mammalian embryo development following fertilization. Influx of extracellular Ca2+ to support the refilling of ER stores is required for sustained Ca2+ oscillations, but the mechanisms underlying this Ca2+ influx are controversial. Although store-operated Ca2+ entry (SOCE) is an appealing candidate mechanism, several groups have arrived at contradictory conclusions regarding the importance of SOCE in oocytes and eggs. To definitively address this question, Ca2+ influx was assessed in oocytes and eggs lacking the major components of SOCE, the ER Ca2+ sensor STIM proteins, and the plasma membrane Ca2+ channel ORAI1. We generated oocyte-specific conditional knockout (cKO) mice for Stim1 and Stim2, and also generated Stim1/2 double cKO mice. Females lacking one or both STIM proteins were fertile and their ovulated eggs displayed normal patterns of Ca2+ oscillations following fertilization. In addition, no impairment was observed in ER Ca2+ stores or Ca2+ influx following store depletion. Similar studies were performed on eggs from mice globally lacking ORAI1; no abnormalities were observed. Furthermore, spontaneous Ca2+ influx was normal in oocytes from Stim1/2 cKO and ORAI1-null mice. Finally, we tested if TRPM7-like channels could support spontaneous Ca2+ influx, and found that it was largely prevented by NS8593, a TRPM7-specific inhibitor. Fertilization-induced Ca2+ oscillations were also impaired by NS8593. Combined, these data robustly show that SOCE is not required to support appropriate Ca2+ signaling in mouse oocytes and eggs, and that TRPM7-like channels may contribute to Ca2+ influx that was previously attributed to SOCE.