Lipidomic profiling of patient-specific induced pluripotent stem cell-derived hepatocyte-like cells

Abstract

Hepatocyte-like cells (HLCs) differentiated from human induced pluripotent stem cells (iPSCs) offer an alternative model for primary human hepatocytes to study lipid aberrations. However, the detailed lipid profile of HLCs is yet unknown. In the current study, functional HLCs were differentiated from iPSCs generated from dermal fibroblasts of three individuals by a 3-step protocol through definitive endoderm (DE) stage. In parallel, detailed lipidomic analyses as well as gene expression profiling of a set of lipid metabolism-related genes were performed during the entire differentiation process from iPSC to HLCs. Additionally, fatty acid (FA) composition of the cell culture media at different stages was determined. Our results show that major alterations in the molecular species of lipids occurring during DE and early hepatic differentiation stages mainly mirror the quality and quantity of the FAs supplied in culture medium at each stage. Polyunsaturated phospholipids and sphingolipids with a very-long FA were produced in the cells at later stage of differentiation. This work uncovers previously unknown lipid composition of iPSC-HLCs and its alterations during the differentiation in conjunction with the expression of key lipid associated genes. Together with biochemical, functional and gene expression measurements the lipidomic analyses allowed us to improve our understanding of the concerted influence of the exogenous metabolite supply and cellular biosynthesis essential for iPSC-HLCs differentiation and function. Importantly, the study describes in detail a cell model that can be applied in exploring e.g. the lipid metabolism involved in the development of fatty liver disease or atherosclerosis.