Wang Xiaoqiu, Johnson Greg A, Burghardt Robert C, Wu Guoyao, Bazer Fuller W
Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, Texas Department of Animal Science, Texas A&M University, College Station, Texas.
Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas.
Biol Reprod. 2015 Feb;92(2):51. doi: 10.1095/biolreprod.114.125971. Epub 2014 Dec 30.
The greatest limitation to reproductive performance in most mammals, including humans, is embryonic mortality, which, in general, claims 20%-40% of the embryos during the peri-implantation period of pregnancy. Both arginine and secreted phosphoprotein 1 (SPP1) are multifunctional molecules that increase significantly in ovine uterine histotroph during early pregnancy. However, little is known about the relationship and underlying mechanisms for synergistic effects of arginine and SPP1, if any, on conceptus (embryo/fetus and associated extraembryonic membranes) development. Therefore, we conducted in vitro experiments using our established ovine trophectoderm cell line (oTr1) isolated from Day 15 ovine conceptuses to determine their proliferative response to individual and synergistic effects of arginine and recombinant SPP1 (rSPP1) that contains an RGD binding sequence. At physiological concentrations, arginine (0.2 mM) stimulated oTr1 cell proliferation 1.7-fold (P < 0.05) at 48 h, whereas rSPP1 (10 ng/ml) had no such effect. However, an additive effect on oTr1 cell proliferation was induced by combination of arginine and SPP1 as compared to the control (2.1-fold increase; P < 0.01), arginine alone (1.3-fold increase; P < 0.05), and rSPP1 alone (1.5-fold increase; P < 0.01). This additive effect was mediated through cooperative activation of the PDK1-Akt/PKB-TSC2-MTORC1 cell signaling cascade. Collectively, results suggest that arginine and SPP1 in histotroph act cooperatively to enhance survival, growth, and development of ovine conceptuses.
在包括人类在内的大多数哺乳动物中，生殖性能的最大限制因素是胚胎死亡率，一般而言，在妊娠植入前期，20%-40%的胚胎会死亡。精氨酸和分泌性磷蛋白1（SPP1）都是多功能分子，在妊娠早期，绵羊子宫组织营养物质中的含量会显著增加。然而，对于精氨酸和SPP1（如果存在）对孕体（胚胎/胎儿及相关的胚外膜）发育的协同作用的关系及潜在机制，我们却知之甚少。因此，我们利用从妊娠第15天的绵羊孕体中分离建立的绵羊滋养外胚层细胞系（oTr1）进行了体外实验，以确定它们对含有RGD结合序列的精氨酸和重组SPP1（rSPP1）的单独及协同作用的增殖反应。在生理浓度下，48小时时精氨酸（0.2 mM）刺激oTr1细胞增殖1.7倍（P < 0.05），而rSPP1（10 ng/ml）则无此作用。然而，与对照组相比，精氨酸和SPP1联合使用对oTr1细胞增殖产生了相加效应（增加2.1倍；P < 0.01），单独使用精氨酸时增加1.3倍（P < 0.05），单独使用rSPP1时增加1.5倍（P < 0.01）。这种相加效应是通过PDK1-Akt/PKB-TSC2-MTORC1细胞信号级联的协同激活介导的。总体而言，结果表明，组织营养物质中的精氨酸和SPP1协同作用可提高绵羊孕体的存活、生长和发育能力。
