Genome wide DNA methylation profiling of whole blood samples from C57BL/6 and DBA/2J healthy mice

Aging of mice can be tracked by DNA methylation changes at specific sites in the genome. In this study, we used the Infinium Mouse Methylation BeadChip to compare such epigenetic modifications in C57BL/6 (B6) and DBA/2J (DBA) mice. There were marked differences in age-associated DNA methylation in these commonly used mouse strains. In B6 the age-associated DNA methylation revealed general age-associated hypomethylation with focused hypermethylation at CpG islands, whereas this was hardly observed in DBA mice. The CpGs with highest age-correlation were overlapping in B6 and DBA and included the genes Hsf4, Prima1, Aspa, and Wnt3a. Notably, Hsf4, Prima1 were also top candidates in previous studies based on whole genome deep sequencing approaches. Furthermore, Hsf4, Aspa, and Wnt3a revealed highly significant age-associated DNA methylation in the homologous regions in human. Taken together, age-associated DNA methylation differs between B6 and DBA, but the most prominent regions are conserved, even in humans. Bisulphite converted DNA from the 35 whole blood samples were hybridised to the Illumina Infinium MouseMethylation BeadChip