Inhibition of trophoblast stem cell potential in chorionic ectoderm coincides with occlusion of the ectoplacental cavity in the mouse.
Inhibition of trophoblast stem cell potential in chorionic ectoderm coincides with occlusion of the ectoplacental cavity in the mouse.
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发表时间：
2002-08
期刊：
影响因子：
4.6
通讯作者：
Gary D Uy;K. Downs;R. Gardner
中科院分区：
文献类型：
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作者：
Gary D Uy;K. Downs;R. Gardner
在着床前小鼠发育的胚泡阶段，极性滋养外胚层与内细胞团（ICM）的紧密接触促进了未分化的二倍体滋养细胞的增殖。然而，ICM/极性滋养外胚层的亲密关系在着床后发育过程中并不维持，这就提出了一个问题，即在此期间如何控制未分化滋养层细胞的生长。通过对成纤维细胞生长因子4依赖性滋养层干细胞潜能的体外空间和时间分析，探讨了着床后发育中滋养层增殖的细胞基础。两个植入后衍生物的极性滋养外胚层-早条纹外胚外胚层和晚条纹绒毛膜外胚层-被显微切割成馏分沿着其proximodistal轴和彻底分离的滋养层干细胞培养。结果表明，具有滋养层干细胞潜能的细胞分布在整个胚外/绒毛膜外胚层，这一观察结果可能归因于单个胚外外胚层细胞在原肠胚形成开始时表现出的非连贯生长模式。此外，滋养层干细胞潜能的细胞的频率在胚胎外/绒毛膜外胚层中稳定增加，直到第一体节对形成，此后以独立于接近尿囊的方式减少。与通过绒毛膜外胚层和外胎盘锥之间的联合闭塞外胎盘腔一致，观察到体内有丝分裂绒毛膜外胚层细胞和体外滋养层干细胞潜能的频率下降。这些研究结果表明，胎盘外腔可能参与维持整个发育中的绒毛膜外胚层的增殖，从而支持其干细胞的潜力。结合以前的观察，我们讨论了充满液体的腔可能在边界组织的发育中发挥一般作用的可能性。
At the blastocyst stage of pre-implantation mouse development, close contact of polar trophectoderm with the inner cell mass (ICM) promotes proliferation of undifferentiated diploid trophoblast. However, ICM/polar trophectoderm intimacy is not maintained during post-implantation development, raising the question of how growth of undifferentiated trophoblast is controlled during this time. The search for the cellular basis of trophoblast proliferation in post-implantation development was addressed with an in vitro spatial and temporal analysis of fibroblast growth factor 4-dependent trophoblast stem cell potential. Two post-implantation derivatives of the polar trophectoderm - early-streak extra-embryonic ectoderm and late-streak chorionic ectoderm - were microdissected into fractions along their proximodistal axis and thoroughly dissociated for trophoblast stem cell culture. Results indicated that cells with trophoblast stem cell potential were distributed throughout the extra-embryonic/chorionic ectoderm, an observation that is probably attributable to non-coherent growth patterns exhibited by single extra-embryonic ectoderm cells at the onset of gastrulation. Furthermore, the frequency of cells with trophoblast stem cell potential increased steadily in extra-embryonic/chorionic ectoderm until the first somite pairs formed, decreasing thereafter in a manner independent of proximity to the allantois. Coincident with occlusion of the ectoplacental cavity via union between chorionic ectoderm and the ectoplacental cone, a decline in the frequency of mitotic chorionic ectoderm cells in vivo, and of trophoblast stem cell potential in vitro, was observed. These findings suggest that the ectoplacental cavity may participate in maintaining proliferation throughout the developing chorionic ectoderm and, thus, in supporting its stem cell potential. Together with previous observations, we discuss the possibility that fluid-filled cavities may play a general role in the development of tissues that border them.