Reprogramming into iP-MSC prevents SA-DNAm changes. (A) Induced pluripotent MSC reveal typical ESC-like morphology and express the pluripotency markers POU5F1, NANOG, and TRA-1-80. (B) Unsupervised hierarchical clustering of global DNAm profiles clearly separates pluripotent cells (iP-MSC and ESC) and it discerns MSC of early and late passage. (C) Scatter plot of DNAm profiles of iP-MSC in comparison to MSC of late passage (P7–P16). In particular, CpG-sites that are hypomethylated upon replicative senescence (green) are hypermethylated in iP-MSC. In contrast, SA-hypermethylated CpG sites (red) are rather hypomethylated in iP-MSC. (D) Differential DNAm upon long-term culture is plotted against methylation changes upon reprogramming into iP-MSC. Overall, SA-DNAm changes are prevented in iP-MSC. (E,F) Venn diagrams demonstrating the overlap of SA-DNAm changes with differential methylation between MSC of late passage with either iP-MSC or ESC.
