Saliva cell type DNA methylation reference panel for epidemiological studies in children

Area of Science:

• Epigenetics
• Molecular Biology
• Pediatric Research

Background:

• Saliva is a valuable biological sample in pediatric research.
• Saliva contains a mix of immune and epithelial cells.
• Cell-type proportions can affect DNA methylation associations in saliva.

Purpose of the Study:

• To develop a saliva cell-type DNA methylation reference panel.
• To estimate cell-type heterogeneity in whole saliva studies.
• To improve epigenetic epidemiology by accounting for cell proportions.

Main Methods:

• Collected saliva from 22 children (ages 7-16).
• Sorted saliva into immune and epithelial cells using filtration and magnetic bead sorting.
• Measured DNA methylation using the Illumina MethylationEPIC BeadChip.

Main Results:

• Identified significant DNA methylation differences between immune and epithelial cells (181,577 sites).
• Found immune cell hypomethylation linked to immune pathways.
• Epithelial cell hypomethylation associated with cornification pathways.

Conclusions:

• Saliva immune and epithelial cells possess distinct DNA methylation profiles.
• The developed reference panel can estimate cell proportions in whole saliva.
• This panel will enhance epigenetic epidemiology by addressing cell-type heterogeneity.