Kaneko K J
Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD, United States.
Curr Top Dev Biol. 2016;120:259-310. doi: 10.1016/bs.ctdb.2016.04.010. Epub 2016 Jun 22.
Unicellular organisms are exquisitely sensitive to nutrient availability in the environment and have evolved elaborate mechanisms to sense the levels and types of nutrients, altering gene expression patterns accordingly to adjust the metabolic activities required to survive. Thus, environmental cues induce adaptive metabolic differentiation through transcriptional and posttranscriptional changes. Similarly, preimplantation embryos are exposed to various environmental cues within the maternal reproductive tract prior to implantation. Because only "simple" culture conditions are required, it is assumed that these embryos are genetically preprogrammed to develop with little influence from the environment, with the exception of few "necessities" provided by the environment. However, a wealth of literature now suggests that the developing embryos are greatly influenced by the maternal environment. Even though the developing embryos have the capacity and plasticity to deal with nutritional imbalance posed by an altered maternal environment, there is often a trade-off to the overall fitness of those embryos later in life. Despite these studies that underline the general importance of the reproductive environment during development, it is thought that the primary driver of mammalian development is strictly genetic and that metabolic adaptation by the preimplantation embryo is secondary to genetic control. In this review, I propose that not only does the maternal environment of developing preimplantation embryos influence developmental potential, pregnancy outcomes, and postnatal disease states, but that it has an active role in induction and potentiation of the first differentiation event, the production of trophectoderm and inner cell mass lineages.
单细胞生物对环境中的营养物质供应极为敏感，并进化出了复杂的机制来感知营养物质的水平和类型，相应地改变基因表达模式，以调整生存所需的代谢活动。因此，环境信号通过转录和转录后变化诱导适应性代谢分化。同样，植入前胚胎在植入前会暴露于母体内生殖道中的各种环境信号。由于只需要“简单”的培养条件，人们认为这些胚胎在基因上预先设定好了发育程序，几乎不受环境影响，除了环境提供的少数“必需品”。然而，现在大量的文献表明，发育中的胚胎受到母体环境的极大影响。尽管发育中的胚胎有能力和可塑性来应对母体环境改变所带来的营养失衡，但这往往会对这些胚胎后期的整体健康产生权衡。尽管这些研究强调了发育过程中生殖环境的普遍重要性，但人们认为哺乳动物发育的主要驱动因素严格来说是基因，植入前胚胎的代谢适应是次要的，由基因控制。在这篇综述中，我提出，发育中的植入前胚胎的母体环境不仅会影响发育潜能、妊娠结局和产后疾病状态，而且在诱导和增强第一次分化事件，即滋养外胚层和内细胞团谱系的产生方面发挥着积极作用。
