Maternal undernutrition induces cell signalling and metabolic dysfunction in undifferentiated mouse embryonic stem cells. Maternal undernutrition induces cell signalling and metabolic dysfunction in undifferentiated mouse embryonic stem cells

The peri-conceptional environment can induce permanent changes in embryo phenotype which alter development and associate with later disease susceptibility. Thus, mouse maternal low protein diet (LPD) fed exclusively during preimplantation is sufficient to cause cardiovascular, metabolic and neurological dysfunction in adult offspring. Embryonic stem cell (ESC) lines were generated from LPD and control NPD C57BL/6 blastocysts and characterised by transcriptomics, metabolomics, bioinformatics and molecular/cellular studies to assess early potential mechanisms in dietary environmental programming. Previously, we showed these lines retain cellular and epigenetic characteristics of LPD and NPD embryos after several passages. Here, three main changes were identified in LPD ESC lines. First, their derivation capacity was reduced but pluripotency marker expression was similar to controls. Second, LPD lines had impaired Mitogen-activated protein kinase (MAPK) pathway with altered gene expression of several regulators (e.g., Maff, Rassf1, JunD), reduced ERK1/2 signalling capacity and poorer cell survival characteristics which may contribute to reduced derivation. Third, LPD lines had impaired glucose metabolism comprising reduced upstream enzyme expression (e.g., Gpi, Mpi) and accumulation of metabolites (e.g., glucose-6-P, fructose-6-P) above the phosphofructokinase (PFK) gateway with PFK enzyme activity reduced. ESC lines may therefore permit investigation of peri-conceptional programming mechanisms with reduced need for animal experimentation. Overall design: Comparative gene expression profiling analysis of RNA-seq data for undifferentiated C57Bl/6 ES cells isolated from mothers on a low protein (LPD) or normal protein (NPD) diet

围孕期环境可诱导胚胎表型发生永久性改变，该改变不仅会影响胚胎发育进程，还与个体成年后的疾病易感性密切相关。已有研究证实，仅在着床前阶段投喂低蛋白日粮（low protein diet，LPD）的孕鼠，其成年后代即可出现心血管、代谢及神经系统功能障碍。本研究从低蛋白日粮（LPD）及对照正常蛋白日粮（normal protein diet，NPD）的C57BL/6小鼠囊胚中构建了胚胎干细胞（Embryonic Stem Cell，ESC）系，并通过转录组学、代谢组学、生物信息学及分子细胞生物学实验对其进行表征，以探究膳食环境编程的早期潜在机制。此前本团队已证实，经多次传代后，这些ESC系仍保留对应LPD与NPD胚胎的细胞及表观遗传特征。本研究中，研究人员在LPD ESC系中发现了三类主要变化：其一，LPD ESC系的建系能力有所下降，但多能性标志物的表达水平与对照组无显著差异；其二，LPD ESC系的丝裂原活化蛋白激酶（Mitogen-activated protein kinase，MAPK）通路功能受损，表现为多个调控基因（如Maff、Rassf1、JunD）的表达异常、ERK1/2信号通路活性降低以及细胞存活能力变差，这可能是其建系能力下降的重要诱因；其三，LPD ESC系存在葡萄糖代谢异常，具体包括糖酵解上游酶（如Gpi、Mpi）的表达量降低、磷酸果糖激酶（phosphofructokinase，PFK）节点上游的代谢物（如葡萄糖-6-磷酸、果糖-6-磷酸）出现蓄积，同时PFK酶活性显著降低。因此，利用ESC系可开展围孕期环境编程机制的相关研究，同时能减少动物实验的依赖。实验设计：对来自低蛋白日粮（LPD）或正常蛋白日粮（NPD）孕鼠的未分化C57Bl/6胚胎干细胞的RNA测序（RNA-seq）数据进行比较基因表达谱分析。