Phosphatidylinositol 3-kinase and Akt participate in the FSH-induced meiotic maturation of mouse oocytes
Phosphatidylinositol 3-kinase and Akt participate in the FSH-induced meiotic maturation of mouse oocytes
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DOI：
10.1002/mrd.20150
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发表时间：
2004-09-01
影响因子：
2.5
通讯作者：
Sato, E
中科院分区：
文献类型：
--
作者：
Hoshino, Y;Yokoo, M;Sato, E
在与多种细胞活动相关的信号转导过程中起关键作用。在本研究中，我们研究了PI 3 K在小鼠卵母细胞减数分裂成熟过程中的作用，使用特异性抑制剂LY 294002。在卵泡刺激素（FSH）诱导的次黄嘌呤介导的卵丘卵母细胞复合体（COCs）减数分裂阻滞的逆转中，LY 294002抑制了胚泡破裂（GVBD）、第一极体（PB 1）发射和卵丘扩张。为了检查LY 294002的作用，将裸露的卵母细胞（DO）在含有卵泡液减数分裂激活固醇（FF-MAS）的培养基中培养，因为已经报道卵母细胞中不存在促性腺激素受体，并且FSH在次黄嘌呤存在下不刺激DO的减数分裂成熟。在FF-MAS诱导的DO成熟中，LY 294002抑制PB 1的释放，但不抑制GVBD。在自发促性腺激素非依赖性卵母细胞成熟中，LY 294002对COC和DO没有影响。Akt/蛋白激酶B是一种丝氨酸-苏氨酸激酶，是PI 3 K通路的关键下游效应子。因此，我们还研究了Akt在FSH诱导的减数分裂成熟过程中的分布。丝氨酸（473）磷酸化的Akt在中期Ⅰ（MI）和中期Ⅱ（M11）卵母细胞中的分布与微管的分布相似，而苏氨酸（308）磷酸化的Akt则分布在中心粒周围物质（PCM）中。LY 294002将MI和MII卵母细胞中Thr（308）磷酸化Akt的量降低至非常低至检测不到的水平。Ser（473）磷酸化Akt在LY 294002处理的MI和MII卵母细胞中分别显示异常分布和非常低至不可检测的表达水平。这些结果表明PI 3 K和Akt参与小鼠减数分裂成熟。(C)2004 Wiley-Liss，Inc.
critical roles in signal transduction processes related to a variety of cellular activities. In the present study, we investigated the role of PI3K during meiotic maturation in mouse oocytes using a specific inhibitor, LY294002. In follicle-stimulating hormone (FSH)-induced reversal of hypoxanthine-mediated meiotic arrest of cumulus oocyte complexes (COCs), LY294002 suppressed germinal vesicle breakdown (GVBD), first polar body (PB1) emission, and cumulus expansion. To examine the effect of LY294002, denuded oocytes (DOs) were cultured in medium containing follicular fluid meiosis-activating sterol (FF-MAS) since absence of gonadotropin receptors in oocytes has been reported and FSH did not stimulate meiotic maturation of DOs in the presence of hypoxanthine. In FF-MAS-induced maturation of DOs, LY294002 suppressed PB1 emission, but not GVBD. In spontaneous gonadotropin-independent oocyte maturation, LY294002 had no effect on COCs and DOs. Akt/protein kinase B, a serine-threonine kinase, is a key downstream effector of the PI3K pathway. Therefore, we also examined the distribution of Akt during FSH-induced meiotic maturation. The distribution of Ser(473) phosphorylated Akt was similar to the localization of microtubules, while Thr(308) phosphorylated Akt was present in the pericentriolar materials (PCM) in metaphase I (MI) and 11 (Mll) oocytes. LY294002 decreased the amount of Thr(308) phosphorylated Akt to very low to undetectable levels in MI and Mll oocytes. Ser(473) phosphorylated Akt showed aberrant distribution and very low to undetectable levels of expression in LY294002-treated MI and Mll oocytes, respectively. These results suggest that PI3K and Akt participate in mouse meiotic maturation. (C) 2004 Wiley-Liss, Inc.