Enrichment of high-functioning human iPS cell-derived hepatocyte-like cells for pharmaceutical research

Human iPS cell-derived hepatocyte-like cells are expected to be utilized in pharmaceutical research. However, the purity of high-functioning hepatocyte-like cells is not high enough. In particular, the purity of cytochrome P450 3A4 (CYP3A4), which is a representative hepatic drug-metabolizing enzyme, positive cells is still quite low (approximately 20%). To address this problem, we established the CYP3A4-NeoR-EGFP transgenic reporter human iPS cell line (CYP3A4-NeoR-EGFP iPS cells) by using genome editing technology. The CYP3A4-NeoR-EGFP iPS cells were differentiated into hepatocyte-like cells, and then the hepatocyte-like cells were treated with neomycin to concentrate the hepatocyte-like cells which strongly express CYP3A4. After the neomycin treatment, the percentage of CYP3A4-positive cells was higher than 80%. The gene expression levels of various drug-metabolizing enzymes, transporters, and hepatic transcription factors were significantly enhanced by neomycin treatment. In addition, the CYP1A2, 2C19, 2D6, and 3A4 activities and biliary excretion capacities were significantly increased by neomycin treatment. We also confirmed that the detection sensitivity of drug-inducing hepatotoxicity was enhanced by neomycin treatment. We succeeded in obtaining human iPS cell-derived hepatocyte-like cells that highly express CYP3A4 at high purity. We believe that our high-purity and high-functioning hepatocyte-like cells could be used to evaluate the risk of drug candidates.