Figure 1.

Stagewise human embryonic stem cell (hESC) differentiation to the hepatocyte lineage. (A): Phase-contrast imaging demonstrated that cells underwent sequential morphological changes during transit from stem cell (day 0), to definitive endoderm (day 3), to hepatoblast (day 10), to hepatocyte (day 18). (B): Immunocytochemistry demonstrating upregulation of HNF4a and albumin during hepatic specification at day 18. Negative controls performed with corresponding immunoglobulin G. The percentage of positive cells is provided in the top right of each panel. This was calculated from four random fields of view and is shown as ± SD. (C), Cyp3A and Cyp1A2 metabolism were assessed in day 18 hepatocyte-like cells using the Promega pGlo system. Experiments were performed in triplicate and measured on a luminometer. The units of activity quoted are relative light units per milliliter of supernatant per milligram of protein. Scale bars = 100 μm. Abbreviations: ALB, albumin; d, day; DAPI, 4′,6-diamidino-2-phenylindole; HNF4a, hepatocyte nuclear factor 4a; IgG, immunoglobulin G RLU, relative light units.