Human induced pluripotent stem cells (hiPSCs) are potentially an invaluable source of cells for regenerative medicine, disease modeling and drug discovery. However, the differentiation of hiPSCs into fully functional hepatocytes remains a major challenge. Despite the importance of the information carried by metabolomes, the exploitation of metabolomics for characterizing and understanding hiPSC differentiation remains largely unexplored. Here, to increase knowledge of hiPSC maturation into mature hepatocytes, we investigated their metabolomics profiles during sequential step-by-step differentiation: definitive endoderm (DE), specification into hepatocytes (HB-pro (hepatoblast progenitors)), progenitor hepatocytes (Pro-HEP) and mature hepatocyte-like cells (HLCs). Metabolomics analysis illustrated a switch from glycolysis-based respiration in DE step to oxidative phosphorylation in HLCs step. DE was characterized by fatty acid beta oxidation, sorbitol metabolism and pentose phosphate pathway, and glutamine and glucose metabolisms as various potential energy sources. The complex lipid metabolism switch was monitored via the reduction of lipid production from DE to HLCs step, whereas high glycerol production occurred mainly in HLCs. The nitrogen cycle, via urea production, was also a typical mechanism revealed in HLCs step. Our analysis may contribute to better understanding of differentiation and suggest new targets for improving iPSC maturation into functional hepatocytes.

人类诱导的多能干细胞（hiPSC）可能是再生医学，疾病建模和药物发现的宝贵细胞来源。然而，将hiPSCs分化为功能齐全的肝细胞仍然是一项重大挑战。尽管代谢组学所携带的信息很重要，但在很大程度上仍未开发利用代谢组学来表征和理解hiPSC分化的方法。在这里，为了增加hiPSC成熟到成熟肝细胞的知识，我们研究了它们在逐步分步分化过程中的代谢组学特征：定形内胚层（DE），肝细胞规格（HB-pro（成肝细胞祖细胞）），祖细胞（Pro- HEP）和成熟的肝样细胞（HLC）。代谢组学分析表明，从DE步骤中基于糖酵解的呼吸转变为HLCs步骤中的氧化磷酸化。DE的特征在于脂肪酸β氧化，山梨糖醇代谢和戊糖磷酸途径，以及谷氨酰胺和葡萄糖代谢作为各种潜在能源。监测复杂的脂质代谢转换通过减少从DE到HLCs的脂质生成，而高甘油生成主要发生在HLC中。通过尿素生产的氮循环也是HLCs步骤揭示的典型机理。我们的分析可能有助于更好地了解分化，并提出改善iPSC成熟为功能性肝细胞的新目标。