Metabolomic profiling during the differentiation of human induced pluripotent stem cells into hepatocyte-like cells

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 hepatocytelike 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.