Department of Experimental Embryology, Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, Jastrzębiec, Poland.
Theriogenology. 2022 Mar 1;180:189-206. doi: 10.1016/j.theriogenology.2021.12.021. Epub 2021 Dec 23.
During mammalian embryo development, the correct formation of the first extraembryonic endoderm lineages is fundamental for successful development. In the periimplantation blastocyst, the primitive endoderm (PrE) is formed, which gives rise to the parietal endoderm (PE) and visceral endoderm (VE) during further developmental stages. These PrE-derived lineages show significant differences in both their formation and roles. Whereas differentiation of the PE as a migratory lineage has been suggested to represent the first epithelial-to-mesenchymal transition (EMT) in development, organisation of the epithelial VE is of utmost importance for the correct axis definition and patterning of the embryo. Despite sharing a common origin, the striking differences between the VE and PE are indicative of their distinct roles in early development. However, there is a significant disparity in the current knowledge of each lineage, which reflects the need for a deeper understanding of their respective specification processes. In this review, we will discuss the origin and maturation of the PrE, PE, and VE during the periimplantation period using the mouse model as an example. Additionally, we consider the latest findings regarding the role of the PrE-derived lineages and early embryo morphogenesis, as obtained from the most recent in vitro models.
在哺乳动物胚胎发育过程中，正确形成第一个胚外内胚层谱系对于成功发育至关重要。在植入前囊胚中，形成原始内胚层 (PrE)，在进一步的发育阶段，它会产生滋养层内胚层 (PE) 和内脏内胚层 (VE)。这些 PrE 衍生的谱系在形成和功能上存在显著差异。虽然已经提出 PE 的分化作为迁移谱系代表了发育中的第一次上皮-间充质转化 (EMT)，但上皮 VE 的组织对于胚胎正确轴定义和模式的形成至关重要。尽管具有共同的起源，但 VE 和 PE 之间的显著差异表明它们在早期发育中的作用不同。然而，目前对于每个谱系的了解存在显著差异，这表明需要更深入地了解它们各自的特化过程。在这篇综述中，我们将以小鼠模型为例，讨论植入前时期 PrE、PE 和 VE 的起源和成熟。此外，我们还考虑了最近在体外模型中获得的关于 PrE 衍生谱系和早期胚胎形态发生作用的最新发现。
