Jornal de pesquisa e terapia com células-tronco

Abstrato

Genomic Instability during Early Differentiation of Embryonic Stem Cells

Clara I Esteban-Pérez, Harold H Moreno-Ortiz, Nancy A Reichert and Dwayne A Wise

Objective: Understanding how genomic instability could be involved in the regulation and establishment of cell lineage commitment during embryonic stem cell differentiation would provide crucial knowledge of stem cell biology. The aim of this study was to determine novel molecular biomarkers located near embryonic developmental genes responsible for embryonic stem cell signals that govern in vitro early cell fate decisions.

Methods: Analysis of genomic instability in 63 single tandem repeats markers from embryoid bodies at 7, 14 and 30 days of culture samples from H1 and H7 embryonic stem cell lines. Mutation frequencies were determined using SP-PCR software from M.D. Anderson Cancer Center. Differences in mutation frequencies were calculated with a two tailed t-test with a p ≤ 0.05.

Results: We determined that the mean values of instability frequencies in embryoid bodies from two different embryonic stem cells lines showed significant differences across time between them. Different markers became unstable during spontaneous differentiation showed higher instability frequencies: one marker associated with pluripotency, nine markers with differentiation, and eight markers with imprinting. Genomic instability influences the loss of pluripotency and the gain of cell lineage specialization. Interestingly, the differentiation potential of embryoid bodies from the two stem cell lines varied. Embryoid bodies from H1 were prone to neuroectoderm differentiation in comparison to those from H7, which showed functional differentiation into mesoderm (contractile cardiac muscle).

Conclusion: We suggest that genomic instability in repetitive regions could be a signal for cell fate decision during differentiation among embryonic stem cell lines. Our results indicate correlation of instability in specific markers located near developmental genes and epigenetic modulators in embryoid bodies that underwent spontaneous differentiation in vitro. The significance of elucidating possible molecular mechanisms of genomic instability and validation of novel biomarkers could potentially support the use of embryonic stem cell are safe source for clinical applications