Department of Embryology, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.
Department of Ecology and Environmental Protection, Institute of Environmental Biology, Faculty of Biology, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland.
Sci Rep. 2021 Nov 2;11(1):21422. doi: 10.1038/s41598-021-00834-1.
During preimplantation development, mammalian embryo cells (blastomeres) cleave, gradually losing their potencies and differentiating into three primary cell lineages: epiblast (EPI), trophectoderm (TE), and primitive endoderm (PE). The exact moment at which cells begin to vary in their potency for multilineage differentiation still remains unknown. We sought to answer the question of whether single cells isolated from 2- and 4-cell embryos differ in their ability to generate the progenitors and cells of blastocyst lineages. We revealed that twins were often able to develop into blastocysts containing inner cell masses (ICMs) with PE and EPI cells. Despite their capacity to create a blastocyst, the twins differed in their ability to produce EPI, PE, and TE cell lineages. In contrast, quadruplets rarely formed normal blastocysts, but instead developed into blastocysts with ICMs composed of only one cell lineage or completely devoid of an ICM altogether. We also showed that quadruplets have unequal capacities to differentiate into TE, PE, and EPI lineages. These findings could explain the difficulty of creating monozygotic twins and quadruplets from 2- and 4-cell stage mouse embryos.
在植入前胚胎发育过程中，哺乳动物胚胎细胞（卵裂球）分裂，逐渐失去其多能性并分化为三个主要细胞谱系：上胚层（EPI）、滋养外胚层（TE）和原始内胚层（PE）。细胞开始在多能性分化的潜力上发生变化的确切时刻仍然未知。我们试图回答这样一个问题：从 2 细胞和 4 细胞胚胎中分离出来的单个细胞在生成囊胚谱系的祖细胞和细胞的能力上是否存在差异。我们发现，双胞胎胚胎经常能够发育成含有原始内细胞团（ICM）和 PE 和 EPI 细胞的囊胚。尽管它们有能力形成囊胚，但双胞胎在生成 EPI、PE 和 TE 细胞谱系的能力上存在差异。相比之下，四胞胎很少形成正常的囊胚，而是发育成只有一个细胞谱系的囊胚，或者完全没有 ICM。我们还表明，四胞胎在分化为 TE、PE 和 EPI 谱系的能力上存在差异。这些发现可以解释从 2 细胞和 4 细胞期的小鼠胚胎中创建同卵双胞胎和四胞胎的困难。
