Piliszek Anna, Grabarek Joanna B, Frankenberg Stephen R, Plusa Berenika
Department of Experimental Embryology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland.
Faculty of Life Sciences, University of Manchester, Manchester, UK.
Mol Hum Reprod. 2016 Oct;22(10):681-690. doi: 10.1093/molehr/gaw002. Epub 2016 Jan 14.
Understanding the mechanisms underlying the first cell differentiation events in human preimplantation development is fundamental for defining the optimal conditions for IVF techniques and selecting the most viable embryos for further development. However, our comprehension of the very early events in development is still very limited. Moreover, our knowledge on early lineage specification comes primarily from studying the mouse model. It is important to recognize that although mammalian embryos share similar morphological landmarks, the timing and molecular control of developmental events may vary substantially between species. Mammalian blastocysts comprise three cell types that arise through two sequential rounds of binary cell fate decisions. During the first decision, cells located on the outside of the developing embryo form a precursor lineage for the embryonic part of the placenta: the trophectoderm and cells positioned inside the embryo become the inner cell mass (ICM). Subsequently, ICM cells differentiate into embryonic lineages that give rise to a variety of tissues in the developing foetus: either the epiblast or extraembryonic primitive endoderm. Successful formation of all three lineages is a prerequisite for implantation and development to term. A comprehensive understanding of the lineage specification processes in mammals is therefore necessary to shed light on the causes of early miscarriages and early pregnancy pathologies in humans.
了解人类植入前发育过程中首次细胞分化事件的潜在机制，对于确定体外受精技术的最佳条件以及选择最具活力的胚胎进行进一步发育至关重要。然而，我们对发育早期事件的理解仍然非常有限。此外，我们对早期细胞谱系特化的认识主要来自对小鼠模型的研究。必须认识到，尽管哺乳动物胚胎具有相似的形态学标志，但发育事件的时间和分子控制在不同物种之间可能存在很大差异。哺乳动物囊胚由三种细胞类型组成，这些细胞类型通过两轮连续的二元细胞命运决定产生。在第一次决定中，位于发育中胚胎外部的细胞形成胎盘胚胎部分的前体细胞谱系：滋养外胚层，而位于胚胎内部的细胞则成为内细胞团（ICM）。随后，内细胞团细胞分化为胚胎谱系，这些谱系会在发育中的胎儿体内产生各种组织：要么是上胚层，要么是胚外原始内胚层。所有三种谱系的成功形成是着床和足月发育的先决条件。因此，全面了解哺乳动物的细胞谱系特化过程对于阐明人类早期流产和早期妊娠病理的原因是必要的。
