Figure 2. Chromosomal aberrations in aged reprogrammed cells.
Left panel, karyotype analysis of the parental NFH2 fibroblast cells and NFH2-derived iPSC lines. NFH2 was karyotypically normal, while all NFH2-iPSC lines exhibited chromosomal aberrations (red circles and light blue circles). Right panel, transcriptional profiling-based analysis of chromosomal integrity. Expression values of single genes in NFH2-iPSC lines were compared to the parental NFH2 fibroblasts and considered over-expressed when fold-change>2 and Bonferroni corrected p-values <10−4. The analysis confirmed significant enrichment in all cases in which karyotyping showed trisomic transformation (red circles). Additional significant enrichments could be observed in NFH2-iPSCs in chromosomes that appeared normal upon karyotyping. Chromosomal translocations (10 to 2) in OiPS3, OiPS6, OiPS8 and chromosomal 1 loss in OiPS16 could not be confirmed by gene expression-based chromosomal enrichment analysis (light blue circles).