Specific age-associated DNA methylation changes in human dermal fibroblasts

Area of Science:

• Epigenetics
• Cellular Biology
• Gerontology

Background:

• Epigenetic modifications, such as DNA methylation, are crucial for cellular differentiation and aging.
• Previous studies showed age-associated methylation changes in mesenchymal stromal cells (MSCs).

Purpose of the Study:

• To compare DNA methylation profiles in dermal fibroblasts from young and elderly individuals.
• To investigate fibroblast differentiation potential and positional memory in vitro.
• To explore cell type-specific epigenetic regulation during aging.

Main Methods:

• Isolation of human dermal fibroblasts from young (<23 years) and elderly (>60 years) donors.
• DNA methylation profiling using the Infinium HumanMethylation27 assay.
• Validation of specific methylation changes using pyrosequencing.

Main Results:

• Fibroblasts showed significant differences in DNA methylation compared to MSCs, with 766 CpG sites hyper-methylated and 752 hypo-methylated.
• Fibroblast DNA methylation profiles clustered by dermal region, indicating positional memory.
• Aging was associated with differential methylation at 75 CpG sites in fibroblasts, notably hyper-methylation in the INK4A/ARF/INK4b locus.
• Age-associated methylation changes in fibroblasts and MSCs were related but often inversely regulated.
• Long-term culture induced consistent methylation changes in both cell types.

Conclusions:

• Aging involves coordinated epigenetic modifications regulated in a cell type-specific manner.
• Fibroblasts exhibit positional memory, maintaining regional identity even after in vitro culture.
• DNA methylation patterns in fibroblasts provide insights into the aging process and cellular differentiation.