Comparative Analysis of Targeted Differentiation of Human Induced Pluripotent Stem Cells (hiPSCs) and Human Embryonic Stem Cells Reveals Variability Associated With Incomplete Transgene Silencing in Retrovirally Derived hiPSC Lines

• Published in: Stem cells translational medicine 2013-02, Vol.2 (2), p.83-93
• Main Authors: Toivonen, Sanna, Ojala, Marisa, Hyysalo, Anu, Ilmarinen, Tanja, Rajala, Kristiina, Pekkanen-Mattila, Mari, Äänismaa, Riikka, Lundin, Karolina, Palgi, Jaan, Weltner, Jere, Trokovic, Ras, Silvennoinen, Olli, Skottman, Heli, Narkilahti, Susanna, Aalto-Setälä, Katriina, Otonkoski, Timo
• Format: Article
• Language: English
• Subjects: Cardiac; Cardiomyocytes; Cell differentiation; Cell Differentiation - genetics; Cell Line; Cell lines; Comparative analysis; Data analysis; Differentiation; DNA methylation; Efficiency; Embryo cells; Embryonic stem cells; Embryonic Stem Cells - cytology; Embryonic Stem Cells - physiology; Embryonic Stem Cells/Induced Pluripotent Stem (iPS) Cells; Epigenetics; Fibroblasts; Gene expression; Gene Silencing; Hepatocyte differentiation; Hepatocytes - cytology; Humans; Kruppel-Like Transcription Factors - genetics; Myocytes, Cardiac - cytology; Nerve Net - physiology; Neural differentiation; Neurons - cytology; Octamer Transcription Factor-3 - genetics; Pluripotency; Pluripotent stem cells; Pluripotent Stem Cells - cytology; Pluripotent Stem Cells - physiology; Proteins; Research funding; Retinal Pigment Epithelium - cytology; Retinal pigmented epithelium; Sendai virus - genetics; Stem cells; Studies; Transduction, Genetic - methods; Transgenes; Transgenes - genetics
• ISSN: 2157-6564; 2157-6580
• DOI: 10.5966/sctm.2012-0047

This study investigated the differences between the differentiation potentials of three human embryonic stem cell (hESC) lines, four retrovirally derived human induced pluripotent stem cell (hiPSC) lines, and one hiPSC line derived with the nonintegrating Sendai virus technology. Cells differentiated from hESCs and hiPSCs showed functional similarities and similar expression of genes characteristic of specific cell types. However, some differences between individual cell lines were also detected, which could be explained by residual activity of viral transgenes and the reactivation of several transgenes in retrovirally derived hiPSC lines. These findings highlight the need for integration‐free reprogramming technologies, resulting in transgene‐free iPSCs, which could also be potentially therapeutically applicable, unlike the retrovirally derived cells used in this study. Functional hepatocytes, cardiomyocytes, neurons, and retinal pigment epithelial (RPE) cells derived from human embryonic stem cells (hESCs) or human induced pluripotent stem cells (hiPSCs) could provide a defined and renewable source of human cells relevant for cell replacement therapies, drug discovery, toxicology testing, and disease modeling. In this study, we investigated the differences between the differentiation potentials of three hESC lines, four retrovirally derived hiPSC lines, and one hiPSC line derived with the nonintegrating Sendai virus technology. Four independent protocols were used for hepatocyte, cardiomyocyte, neuronal, and RPE cell differentiation. Overall, cells differentiated from hESCs and hiPSCs showed functional similarities and similar expression of genes characteristic of specific cell types, and differences between individual cell lines were also detected. Reactivation of transgenic OCT4 was detected specifically during RPE differentiation in the retrovirally derived lines, which may have affected the outcome of differentiation with these hiPSCs. One of the hiPSC lines was inferior in all directions, and it failed to produce hepatocytes. Exogenous KLF4 was incompletely silenced in this cell line. No transgene expression was detected in the Sendai virus‐derived hiPSC line. These findings highlight the problems related to transgene expression in retrovirally derived hiPSC lines.