Role of oocyte-secreted growth differentiation factor 9 in the regulation of mouse cumulus expansion
Role of oocyte-secreted growth differentiation factor 9 in the regulation of mouse cumulus expansion
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DOI：
10.1210/en.2005-0098
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发表时间：
2005-06-01
期刊：
影响因子：
4.8
通讯作者：
Gilchrist, RB
中科院分区：
文献类型：
--
作者：
Dragovic, RA;Ritter, LJ;Gilchrist, RB
卵子分泌因子是小鼠卵丘-卵母细胞复合体扩张所必需的，而卵丘-卵母细胞复合体是排卵所必需的。卵母细胞分泌的生长分化因子9(GDF9)通过骨形态发生蛋白受体II传递信号，目前是卵丘扩张使能因子的主要候选分子。本研究旨在确定GDF9是否是小鼠卵丘扩张的启动因子。收集小鼠的卵丘-卵母细胞复合体，并通过显微手术去除卵母细胞以产生卵母细胞切除(OOX)复合体。单独用FSH或重组小鼠GDF9处理的OOX复合体不能扩张，而在FSH存在的情况下，GDF9、转化生长因子β1或与卵母细胞共培养都能诱导OOX复合体的扩张。一种特异性的GDF9中和抗体mAb-GDF9-53可中和GDF9引起的OOX复合体的扩张，但不能抑制与卵母细胞共培养的OOX复合体的扩张。实时荧光定量RT-PCR结果显示，卵母细胞和GDF9对OOXs的透明质酸合成酶2(HAS2)基因表达上调4~6倍。单抗GDF9-53可减弱GDF9诱导的OOX HAS2表达，但不能抑制卵母细胞诱导的HAS2表达。转化生长因子β拮抗剂可中和转化生长因子β诱导的OOX复合体的扩张，但与单抗GDF9-53联合应用也不能中和卵母细胞的扩张。此外，已知的GDF9拮抗剂--骨形态发生蛋白受体II胞外区的一部分可完全拮抗GDF9诱导的扩张，但仅部分中和卵母细胞诱导的扩张。这项研究提供了进一步的证据，证明GDF9和转化生长因子β一样，可以使卵泡刺激素诱导的卵丘扩张，但更重要的是，证明了GDF9和转化生长因子β单独或两个共同作用都不能解释调节小鼠卵丘扩张的关键卵母细胞分泌因子。
Oocyte-secreted factors are required for expansion of the mouse cumulus-oocyte complex, which is necessary for ovulation. Oocyte-secreted growth differentiation factor 9 (GDF9) signals through the bone morphogenetic protein receptor II and is currently the primary candidate molecule for the cumulus-expansion enabling factor. This study was conducted to determine whether GDF9 is the mouse cumulus-expansion enabling factor. Cumulus-oocyte complexes were collected from mice, and the oocyte was microsurgically removed to generate an oocytectomized (OOX) complex. OOX complexes treated with FSH alone or recombinant mouse GDF9 alone failed to expand, whereas expansion was induced in the presence of FSH by GDF9, TGF beta 1, or coculture with oocytes. A specific GDF9-neutralizing antibody, mAb-GDF9-53, neutralized the expansion of OOX complexes in response to GDF9 but not the expansion of OOX complexes cocultured with oocytes. Using real-time RT-PCR, hyaluronan synthase 2 (HAS2) mRNA expression by OOXs was up-regulated 4- to 6-fold by oocytes and GDF9. Monoclonal neutralizing antibody-GDF9-53 attenuated GDF9-induced OOX HAS2 expression but not oocyte-induced HAS2 expression. A TGF beta antagonist neutralized TGF beta-induced, but not oocyte-induced, expansion of OOX complexes, and when combined with monoclonal neutralizing antibody-GDF9-53 also failed to neutralize oocyte-induced expansion. Furthermore, a soluble portion of the bone morphogenetic protein receptor II extracellular domain, which is a known GDF9 antagonist, completely antagonized GDF9-induced expansion but only partially neutralized oocyte-induced expansion. This study provides further evidence that like TGF beta, GDF9 can enable FSH-induced cumulus expansion, but more importantly, demonstrates that neither GDF9 nor TGF beta alone, nor the two in unison, account for the critical oocyte-secreted factors regulating mouse cumulus expansion.