Cell death in fetal oocytes - Many players for multiple pathways
Cell death in fetal oocytes - Many players for multiple pathways
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DOI：
10.4161/auto.5410
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发表时间：
2008-02-16
期刊：
影响因子：
13.3
通讯作者：
Klinger, Francesca Gioia
中科院分区：
文献类型：
--
作者：
De Felici, Massimo;Lobascio, Anna Maria;Klinger, Francesca Gioia
我们设计了一个短期培养系统，使我们能够定义胎儿卵母细胞程序性细胞死亡（PCD）的新特征，并强调这一过程的新方面。在允许减数分裂进行的条件下培养的小鼠胎儿卵母细胞经历凋亡变性，如通过TUNEL染色、DNA梯状条带、膜联蛋白V结合、PARP裂解和通常的半胱天冬酶活化所揭示的。然而，透射电镜观察显示，经常性的非典型凋亡形态的特点是没有染色质边集和核碎片，卵母细胞与自噬和坏死的功能也被观察到。此外，在荧光显微镜下，TUNEL+卵母细胞的亚群在形态上看起来健康，并且没有显示出可检测的半胱天冬酶活性。最后，半胱天冬酶抑制剂能够减缓但不能消除卵母细胞死亡，而钙蛋白酶抑制剂I在培养4天后显著减少TUNEL+卵母细胞的数量，雷帕霉素（mTOR抑制剂）在第3天和第4天增加这些数量。这些观察结果与显示在经历细胞死亡的细胞凋亡诱导因子和Beclin 1（分别是半胱天冬酶非依赖性和自噬性细胞死亡的两个重要参与者）的培养的卵母细胞中表达的结果一起，证明胎儿卵母细胞凋亡并且能够激活各种形式的细胞死亡的几个参与者。然而，在这些卵母细胞中不同的细胞死亡途径之间的因果关系仍有待确定，刺激引起这些途径在体外和体内的激活也澄清。
We devised a short-term culture system allowing us to define novel characteristics of programmed cell death (PCD) of fetal oocytes and to underscore new aspects of this process. Mouse fetal oocytes cultured in conditions allowing meiotic progression underwent apoptotic degeneration as revealed by TUNEL staining, DNA ladder, Annexin V binding, PARP cleavage and, usually, caspase activation. TEM observations show, however, recurrent atypical apoptotic morphologies characterized by the absence of chromatin margination and nuclear fragmentation; oocytes with autophagic and necrotic features are also observed. Moreover, under the fluorescence microscope a subpopulation of TUNEL+ oocytes appear morphologically healthy and do not show detectable caspase activity. Finally, caspase inhibitors are able to slow down, but not to abolish, oocyte cell death, whereas calpain inhibitor I significantly reduces the number of TUNEL+ oocytes after 4 days of culture, and rapamycin (mTOR inhibitor) increases such numbers both at day 3 and 4. These observations together with results showing expression in cultured oocytes undergoing cell death of apoptosis inducing factor and Beclin 1, two important players of caspase-independent and autophagic cell death, respectively, demonstrate that fetal oocytes posses and are able to activate several players of various forms of cell death. However, causal correlation among different cell death pathways in such oocytes remains to be determined and stimuli causing the activation of these pathways in vitro and in vivo also clarified.