Fig. 4

Age-associated DNAm changes in primary myelofibrosis. a–d The correlation between epigenetic age predictions with chronological age and the difference between predicted and chronological age (delta-age) was determined with epigenetic clocks developed by a,b) Horvath [26] and c,d) Han et al. [25]. Statistical significance was determined using an unpaired t-test. e–h The DNAm at an age-associated region in PDE4C was analyzed by bisulfite amplicon sequencing (BA-seq). The heatmaps exemplify the presence of methylated (red) and non-methylated (blue) CpGs within the PDE4C amplicon, covering 26 neighboring CpGs. The age-associated CpG of the aging signature is indicated by arrow. Exemplary heatmaps are depicted for e) a healthy donor, and f) a PMF patient blood sample of the same age. The frequency of reads is clustered according to their DNAm patterns. The same analysis was performed in colony-forming units (CFUs) on day 14 that were either g) a wild type (WT), or h) harbored the JAK2 V617F mutation. Unlike the blood samples from PMF patients or controls, the CFUs exhibited a distinct DNAm pattern that appears to reflect the clonal characteristics of the colony-initiating cells