Regulation of cell survival in the pregnant rat endometrium.

妊娠的识别和维持是一个复杂的过程，涉及母体和胚胎的信号。啮齿类动物着床早期子宫内膜上皮细胞发生凋亡。随后，基质细胞经历蜕膜化，随后是基底蜕膜（DB）退化，涉及蜕膜细胞的凋亡。未能建立这样的交流已被证明是哺乳动物不育的最重要原因。然而，子宫内膜细胞凋亡的分子机制尚未确定。有趣的是，我们的实验室已经表明，个别TGF-β亚型（TGF-β 1，-b2和-b3）是不同的表达在子宫在大鼠怀孕期间：TGF-β 1和TGF-β 2是在植入和DB回归，而TGF-β 3亚型只存在于DB回归。我们还提供了证据表明，不同的TGF-β可以激活子宫内膜细胞中不同的信号通路。这强烈表明，TGF-β可以发挥重要作用，这取决于怀孕期间的情况，我们假设性类固醇孕酮和17 b-雌二醇，怀孕的激素，也可能参与这一过程。该研究计划的总体和长期目标是检查和了解在妊娠的两个重要阶段（1）胚胎植入和2）DB消退期间子宫内膜中TGF-β亚型的表达调节以及内分泌、旁分泌和自分泌活性。上皮细胞和基质细胞以及来自不同妊娠日、假孕和发情周期的整个大鼠子宫将用于体内和体外研究。实验方法将包括分子和生物化学技术，上调与表达载体和下调的关键蛋白质使用shRNA，生物化学在体内抑制信号通路，凋亡原位和流式细胞术和免疫荧光。从这些研究中获得的信息将有助于了解TGF-β亚型在这些关键生殖情况下的重要性，并将为成功建立和维持妊娠提供重要线索。

Recognition and maintenance of pregnancy are complex processes involving both maternal and embryonic signals. In the rodents during early implantation, endometrial epithelial cells undergo apoptosis. Later, the stromal cells undergo decidualization, which is followed by decidua basalis (DB) regression, involving apoptosis of decidual cells. The failure to establish such a communication has been shown to be the most important cause of infertility among mammals. However, the molecular mechanisms governing endometrial cell apoptosis are not yet defined. Interestingly, our laboratory has showed that individual TGF-b isoforms (TGF-b1, -b2 and -b3) are differently expressed in the uterus during rat pregnancy: TGF-b1 and TGF-b2 are present during implantation and DB regression, whereas TGF-b3 isoform is only present during DB regression. We have also provided evidence that distinct TGF-b can activate distinct signaling pathways in endometrial cells. This strongly suggests that TGF-b can play an important role depending of the situation during pregnancy and we hypothesize that sex steroids progesterone and 17b-estradiol, the hormones of pregnancy, might also be involved in this process. The overall and long term objective of the proposed research program is to examine and understand the regulation of expression as well as the endocrine, paracrine and autocrine activity of the TGF-b isoforms in the endometrium during the two important phases of pregnancy: 1) embryo implantation and 2) DB regression. Epithelial and stromal cells as well as whole rat uteri from different Days of pregnancy, pseudopregnat and estrous cycle will be used for in vivo and in vitro studies. Experimental approaches will include molecular and biochemical techniques, upregulation with expression vectors and down-regulation of key proteins using shRNA, biochemical in vivo inhibition of signaling pathways, apoptosis in situ and by flow cytometry and immunofluorescence. Information gained from these studies will help to understand the importance of TGF-b isoforms during these critical reproductive situations and will provide important clues for successful establishment and maintenance of pregnancy.