Han Zhiming, Vassena Rita, Chi Maggie M Y, Potireddy Santhi, Sutovsky Miriam, Moley Kelle H, Sutovsky Peter, Latham Keith E
Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Am J Physiol Endocrinol Metab. 2008 Oct;295(4):E798-809. doi: 10.1152/ajpendo.00683.2007. Epub 2008 Jun 24.
Cloned mouse embryos display a marked preference for glucose-containing culture medium, with enhanced development to the blastocyst stage in glucose-containing medium attributable mainly to an early beneficial effect during the first cell cycle. This early beneficial effect of glucose is not displayed by parthenogenetic, fertilized, or tetraploid nuclear transfer control embryos, indicating that it is specific to diploid clones. Precocious localization of the glucose transporter SLC2A1 to the cell surface, as well as increased expression of glucose transporters and increased uptake of glucose at the one- and two-cell stages, is also seen in cloned embryos. To examine the role of glucose in early cloned embryo development, we examined glucose metabolism and associated metabolites, as well as mitochondrial ultrastructure, distribution, and number. Clones prepared with cumulus cell nuclei displayed significantly enhanced glucose metabolism at the two-cell stage relative to parthenogenetic controls. Despite the increase in metabolism, ATP content was reduced in clones relative to parthenotes and fertilized controls. Clones at both stages displayed elevated concentrations of glycogen compared with parthenogenetic controls. There was no difference in the number of mitochondria, but clone mitochondria displayed ultrastructural alterations. Interestingly, glucose availability positively affected mitochondrial structure and localization. We conclude that cloned embryos may be severely compromised in terms of ATP-dependent processes during the first two cell cycles and that glucose may exert its early beneficial effects via positive effects on the mitochondria.
克隆的小鼠胚胎对含葡萄糖的培养基表现出明显的偏好，在含葡萄糖的培养基中发育至囊胚阶段的能力增强，这主要归因于第一个细胞周期期间的早期有益作用。孤雌生殖、受精或四倍体核移植对照胚胎未表现出葡萄糖的这种早期有益作用，表明它对二倍体克隆具有特异性。在克隆胚胎中还可见葡萄糖转运蛋白SLC2A1早熟地定位于细胞表面，以及葡萄糖转运蛋白的表达增加和在单细胞和二细胞阶段葡萄糖摄取增加。为了研究葡萄糖在克隆胚胎早期发育中的作用，我们检测了葡萄糖代谢及相关代谢物，以及线粒体的超微结构、分布和数量。与孤雌生殖对照相比，用卵丘细胞核制备的克隆在二细胞阶段表现出显著增强的葡萄糖代谢。尽管代谢增加，但与孤雌生殖胚胎和受精对照相比，克隆中的ATP含量降低。与孤雌生殖对照相比，两个阶段的克隆中糖原浓度均升高。线粒体数量没有差异，但克隆的线粒体表现出超微结构改变。有趣的是，葡萄糖的可利用性对线粒体结构和定位有积极影响。我们得出结论，克隆胚胎在前两个细胞周期中可能在依赖ATP的过程方面受到严重损害，并且葡萄糖可能通过对线粒体的积极作用发挥其早期有益作用。
