IntroductionThe influence of genetic background on the ability to generate induced pluripotent stem cells (iPSCs) has the potential to impact future applications, but has yet to be examined in detail. The purpose of this study was to determine if genetic background affects the efficiency of generating iPSCs during early reprogramming as well as the pluripotent stability of the iPSCs during later stages of reprogramming.
Mouse embryonic fibroblasts (MEFs) were isolated from six strains of mice (NON/LtJ; C57BL/6J; DBA/2J; BALB/cJ; 129S1/SvlmJ; CAST/EiJ) that were selected based on genetic diversity and differences in ability to produce embryonic stem cell (ESC) lines.
MEFs were reprogrammed via doxycycline-inducible lentiviral transduction of murine Oct4, Klf4, Sox2, and c-Myc. Differences in efficiency to generate iPSCs were assessed on primary transformation plates by comparing the total number of colonies, the percentage of colonies positive for alkaline phosphatase staining and the percentage of cells positive for SSEA1.
iPSC colonies were expanded to establish doxycycline-independent cell lines whose pluripotency was then evaluated via ability to form teratomas in NOD.CB17-Prkdcscid/J mice. Proliferation of non-transduced parent MEFs from each strain was also examined over ten days under conditions that simulated reprogramming.
NON/LtJ and CAST/EiJ strains were more efficient than other strains in generating iPSCs for all parameters measured on primary transformation plates and parent MEFs from these strains were more proliferative than those from other strains.
Doxycycline-independent iPSC lines were established using standard conditions for all strains except BALB/cJ, which required a higher concentration (5x) of Leukemia Inhibitory Factor (LIF). iPSCs from all strains were capable of producing teratomas in NOD.CB17-Prkdcscid/J mice.
The results of this study suggest that genetic background does affect iPSC generation and pluripotent stability.
In addition, our results demonstrate that strain differences in efficiency to generate iPSCs during the early stages of reprogramming are correlated with those observed in proliferation of parent MEFs. These findings have important implications both for future iPSC applications as well as for future investigation into determining the genes responsible for reprogramming efficiency and stability.
Author: Lauren V SchnabelChristian M AbratteJohn C SchimentiTeresa L SouthardLisa A Fortier Credits/Source: Stem Cell Research &Therapy 2012, 3:30
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