Mutation frequency dynamics in HPRT locus in culture-adapted human embryonic stem cells and induced pluripotent stem cells correspond to their differentiated counterparts.
The genomic destabilization associated with the adaptation of human embryonic stem cells (hESCs) to culture conditions or the reprogramming of induced pluripotent stem cells (iPSCs) increases the risk of tumorigenesis upon the clinical use of these cells and decreases their value as a model for cell biology studies. Base excision repair (BER), a major genomic integrity maintenance mechanism, has been shown to fail during hESC adaptation. Here, we show that the increase in the mutation frequency (MF) caused by the inhibition of BER was similar to that caused by the hESC adaptation process. The increase in MF reflected the failure of DNA maintenance mechanisms and the subsequent increase in MF rather than being due solely to the accumulation of mutants over a prolonged period, as was previously suggested. The increase in the ionizing-radiation-induced MF in adapted hESCs exceeded the induced MF in nonadapted hESCs and differentiated cells. Unlike hESCs, the overall DNA maintenance in iPSCs, which was reflected by the MF, was similar to that in differentiated cells regardless of the time spent in culture and despite the upregulation of several genes responsible for genome maintenance during the reprogramming process. Taken together, our results suggest that the changes in BER activity during the long-term cultivation of hESCs increase the mutagenic burden, whereas neither reprogramming nor long-term propagation in culture changes the MF in iPSCs.
1 Department of Biology, Faculty of Medicine, Masaryk University , Brno, Czech Republic .
Miriama
M
Krutá
Monika
M
Šeneklová
Jan
J
Raška
Anton
A
Salykin
Lenka
L
Zerzánková
Martin
M
Pešl
Eva
E
Bártová
Michal
M
Franek
Aneta
A
Baumeisterová
Stanislava
S
Košková
Kai J
KJ
Neelsen
Aleš
A
Hampl
Petr
P
Dvořák
Vladimír
V
Rotrekl
D002454:Cell Differentiation / Q000528:radiation effects; D002460:Cell Line; D005720:Gamma Rays; D056426:Genetic Loci; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics* / Q000378:metabolism; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D059645:Mutation Rate
D007041:Hypoxanthine Phosphoribosyltransferase