Study on regulation of placental functions : Involvement of ovarian factors in the mechanism.

胎盘在胎儿的生长和存活中起着至关重要的作用。由于其涉及在母亲和胎儿之间运输营养物和废物的多种功能，调节母亲和胎儿免疫系统以防止彼此排斥，以及其维持妊娠的内分泌功能，在妊娠期间维持母体代谢状态。胚胎的成功发育完全依赖于胎盘的功能。考虑到这些多种功能，不仅是不断需要的功能，而且还有妊娠阶段特异性事件，如胎盘催乳素合成，胎盘被认为表达丰富的生物活性分子。在这一系列的实验中，我们分析和鉴定了近800种在大鼠胎盘质膜上表达的阶段特异性蛋白。我们还在大鼠胎盘中克隆了编码新的催乳素（PPL）样分子PL-lm和PLP-D的cDNA。PL-lm RNA在妊娠中期特异性表达，PLP-D在妊娠晚期特异性表达。除了这些胎盘PPL样分子外，我们还发现GD 3和GM 3是胎盘中主要的神经节苷脂。该组合物在大鼠胎盘中以阶段特异性方式变化。利用过期妊娠模型和上述各阶段特异性指标，明确了胎盘的阶段特异性功能受母体卵巢因素的控制。胎盘这些阶段特异性功能的表达与滋养层细胞的分化和细胞组成的变化有关。此外，我们还得到证据表明，CpG岛或启动子区域的DNA甲基化参与胎盘特异性基因的表达和胎盘的分化。

The placenta plays an essential role in fetal growth and survival. maintenance of maternal metabolic status during pregnancy by virtue of its multiple functions relating to the transport of nutrients and waste between mother and tetus, moduiating of the matemal and fetal immune systems to prevent rejection of each other, and its endocrine function of maintaining the pregnancy. Successful development of errbryo is totally dependent on placental function. Considering these multiple functions, not only functions that are required constantly but also pregnancy stage specific events such as placental lactogen synthesis, the placenta is thought to express an abundance of biologically active molecules. In the series of experiments, we have analyzed and identified the almost 800 proteins which are stage-specifically expressed on the placental plasma membrane of the rat placenta. We have also cloned the cDNAs encoding novel prolactin (PPL) like molecules, PL-lm and PLP-D,in the rat placenta. PL-lm RNA is specitically expressed at mid-pregnancy, and PLP-D is specific to late pregnancy. In addition to these placental PPL-like molecules, we found GD3 and GM3 as the main gangliosides in the placenta. The composition changes stage specific manner in the rat placenta. Using prolonged pregnancy models and the various stage-specific indexes as mentioned above, it became clear that the stage-specific functions of placenta are controlled by matemal ovarian factors. Expression of these stage-specific functions of the placenta is related to the differentiation of trophoblasts and changes in the cellular composition. Furthermore, we got the evidence indicating that methylation of DNA of CpG islands or in the promoter regions is involved in the placental specific gene-expression and differentiation of the placenta.