CD4⁺ and CD8⁺ T-Cell-Specific DNA Cytosine Methylation Differences Associated With Obesity

Area of Science:

• Epigenetics
• Immunology
• Metabolic Disease Research

Background:

• Lifestyle factors linked to obesity can influence epigenome-regulated gene expression.
• Previous studies on obesity-related epigenetic changes often used whole blood, masking cell-specific variations.
• Understanding leukocyte-specific epigenetic alterations is crucial for a nuanced view of obesity's impact.

Purpose of the Study:

• To investigate leukocyte-specific differences in DNA 5´-methylcytosine (5mC) levels associated with obesity.
• To compare epigenetic changes in distinct immune cell types (CD4+ T cells, CD8+ T cells, CD16+ neutrophils) in women with normal weight versus obesity.

Main Methods:

• Isolation of CD4+ T cells, CD8+ T cells, and CD16+ neutrophils from peripheral blood.
• Measurement of 5mC levels across over 450,000 CG sites within these isolated cell types.
• Statistical analysis to identify differentially methylated sites and associations with obesity and visceral adipose tissue.

Main Results:

• Significant differences in DNA methylation were observed between women with obesity and normal weight in CD4+ T cells (19 sites) and CD8+ T cells (16 sites).
• No significant differentially methylated sites were found in CD16+ neutrophils.
• Visceral adipose tissue levels strongly correlated with methylation at 79 CG sites in CD4+ T cells, including regulatory sites in the CLSTN1 gene promoter.

Conclusions:

• The methylomes of different leukocyte types exhibit distinct responses to obesity and visceral adipose tissue.
• Specific differentially methylated sites in CD4+ and CD8+ T cells show biological relevance to obesity.
• These findings highlight the importance of cell-type-specific epigenetic analysis in obesity research.