Department of Obstetrics and Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Stem Cells Dev. 2013 May 15;22(10):1564-75. doi: 10.1089/scd.2012.0352. Epub 2013 Mar 11.
The AMP-activated protein kinase (AMPK) mediates rapid, stress-induced loss of the inhibitor of differentiation (Id)2 in blastocysts and trophoblast stem cells (TSC), and a lasting differentiation in TSC. However, it is not known if AMPK regulates other potency factors or regulates them before the blastocyst stage. The caudal-related homeodomain protein (Cdx)2 is a regulatory gene for determining TSC, the earliest placental lineage in the preimplantation mouse embryo, but is expressed in the oocyte and in early cleavage stage embryos before TSC arise. We assayed the expression of putative potency-maintaining phosphorylated Cdx2 ser60 in the oocyte, two-cell stage embryo, blastocyst, and in TSC. We studied the loss of Cdx2 phospho ser60 expression induced by hyperosmolar stress and its underlying mechanisms. Hyperosmolar stress caused rapid loss of nuclear Cdx2 phospho ser60 and Id2 in the two-cell stage embryo by 0.5 h. Stress-induced Cdx2 phospho ser60 and Id2 loss is reversed by the AMPK inhibitor compound C and is induced by the AMPK agonist 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide in the absence of stress. In the two-cell stage embryo and TSC hyperosmolar, stress caused AMPK-mediated loss of Cdx2 phospho ser60 as detected by immunofluorescence and immunoblot. We propose that AMPK may be the master regulatory enzyme for mediating stress-induced loss of potency as AMPK is also required for stress-induced loss of Id2 in blastocysts and TSC. Since AMPK mediates potency loss in embryos and stem cells it will be important to measure, test mechanisms for, and manage the AMPK function to optimize the stem cell and embryo quality in vitro and in vivo.
AMP 激活的蛋白激酶 (AMPK) 介导快速的应激诱导的分化抑制因子 (Id)2 在囊胚和滋养层干细胞 (TSC) 中的丢失，以及 TSC 的持久分化。然而，尚不清楚 AMPK 是否调节其他效力因子，或者是否在囊胚阶段之前调节它们。尾相关同源域蛋白 (Cdx)2 是决定 TSC 的调节基因，TSC 是植入前小鼠胚胎中最早的胎盘谱系，但在 TSC 出现之前，它在卵母细胞和早期卵裂期胚胎中表达。我们检测了假定的维持效力的磷酸化 Cdx2ser60 在卵母细胞、二细胞期胚胎、囊胚和 TSC 中的表达。我们研究了高渗应激诱导的 Cdx2 磷酸化 ser60 表达的丢失及其潜在机制。高渗应激在 0.5 小时内导致二细胞期胚胎中核 Cdx2 磷酸化 ser60 和 Id2 的快速丢失。AMPK 抑制剂复合物 C 逆转应激诱导的 Cdx2 磷酸化 ser60 和 Id2 丢失，并且在没有应激的情况下，AMPK 激动剂 5-氨基-1-β-D-核糖呋喃基-咪唑-4-羧酰胺诱导其丢失。在二细胞期胚胎和 TSC 中，高渗应激通过免疫荧光和免疫印迹检测到 AMPK 介导的 Cdx2 磷酸化 ser60 丢失。我们提出，AMPK 可能是介导应激诱导的效力丧失的主调节酶，因为 AMPK 也需要在囊胚和 TSC 中应激诱导的 Id2 丢失。由于 AMPK 在胚胎和干细胞中介导效力丧失，因此测量、测试和管理 AMPK 功能以优化体外和体内的干细胞和胚胎质量将非常重要。
