Acute Hyperinsulinemia during Hyperinsulinemic-Euglycemic Clamp Influences DNA Methylation and Gene Expression in Peripheral Blood Cells of Adult Men

초록

Background: Acute hyperinsulinemia may directly affect blood cells. In this study a hyperinsulinemic-euglycemic clamp (HEC) and multiomics methods were used to explore the epigenetic regulation by hyperinsulinemia in blood cells.Methods: To assess short-term changes in DNA methylation (within 2 hours), blood samples were collected from five non-diabetic adults before and after HEC. mRNA sequencing (mRNA-seq) and targeted bisulfite sequencing (methyl-seq) were performed. Using mRNA-seq, 697 differentially expressed genes (DEGs) were identified, and methyl-seq was used to select those with changes in promoter or gene body methylation. In vitro validation study was also performed in THP1 and 3T3–L1 cells after acute insulin treatment.Results: Among the 697 DEGs, 119 (henceforth, ‘methyl-DEGs’) showed methylation changes. Of these 697 DEGs, 45 (‘publictrait- DEGs’) were associated with pathways such as oxidative stress, insulin signaling, inflammation, and carbohydrate metabolism. Interaction networks between methyl-DEGs and public-trait-DEGs revealed that six genes (<i>B3GALNT1, ESR1, FGF4, PER1, PRKAR1B</i>, and <i>TNFSF4</i>) were affected by DNA methylation and linked to insulin response or diabetes. In response to acute insulin treatment, <i>ESR1, PRKAR1B, PER1</i>, and <i>B3GALNT1</i> expression decreased in THP1 cells. Similar trends were seen in 3T3–L1 cells, except <i>B3GALNT1. PER1</i> displayed consistent and significant downregulation across the clamp study and the two cell lines, indicating it as a key circadian-responsive gene under acute hyperinsulinemia.Conclusion: These results provide epigenetic evidence for the role of DNA methylation in CpG regions and gene bodies in hyperinsulinemia- mediated regulation of gene expression in blood cells, which warrants further studies in relation to diabetes-related pathophysiology.

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