Figure 2
Functional analysis of iPS cell-derived hepatocyte-like cells. RT-PCR analysis showed progressive increase of mRNA expression of hepatocyte-enriched markers, such as albumin, the urea cycle enzyme carbamoyl phosphate synthetase, and transferrin over the course of differentiation program (A,B). However, gene expression levels of such markers in differentiated iPS cells (day 19) were much lower than those of isolated hepatocytes. Moreover, strong expression of α-fetoprotein at day 19 indicated that the final product of the differentiation program was not fully matured hepatocytes. Real-time PCR analysis of gene expression levels relative to β actin was performed using three independent experiments. *p < 0.01 iPS cells vs differentiated cells (day 19). †p < 0.01 differentiated cells (day 2) vs differentiated cells (day 19). ‡p < 0.01 differentiated cells (day 5) vs differentiated cells (day 19). §p < 0.01 differentiated cells (day 12) vs differentiated cells (day 19). An ELISA assay showed that the amount of albumin produced by differentiated cells (day 19) was 6.45 ± 0.78 ng/24h/105 cells (C). *p < 0.01 iPS cells vs differentiated cells (day 12). †p < 0.01 iPS cells vs differentiated cells (day 19). ‡p < 0.01 differentiated cells (day 12) vs differentiated cells (day 19). The ELISA data shown are means ± SDs from three independent experiments.