DNA methylation is associated with oxidative stress and genomic deregulation in diabetes mellitus

Abstract

Abstract Retrotransposons may undergo aberrant methylation leading to genomic deregulation in diabetes mellitus. The present study evaluated the methylation of retrotransposons namely Alu, B1, and LINE-1 elements in glucose-induced endothelial cells (ECs) and T1DM. The correlation between methylation of these retrotransposons and oxidative stress was investigated. Additionally, methylation of FN1, VEGFa, and EDN1 genes was analyzed. Hot start PCR of the bisulfite converted DNA isolated from the ECs and kidneys for the methylation of retrotransposons was analyzed. Quantification of methylated DNA in ECs was performed by ELISA. The methylation of the FN1, VEGFa, and EDN1 genes was examined. Oxidative stress was evaluated by measuring the superoxide anion, mitochondrial reactive oxygen species (ROS), 8-Hydroxyguanosine (8-OHdG), and NF-kappaB p(65). Hypermethylation of Alu and LINE-1 elements occurred in the high glucose- induced ECs. B1 hypermethylation was observed in the kidneys of T1DM mice. Hyperglycemia resulted in LINE-1 hypermethylation in the kidneys of T1DM mice. Hypermethylation of the FN1, VEGFa and EDN1 genes occurred in the high glucose-induced ECs and diabetic kidneys. Hypermethylation of the retrotransposons, oxidative stress and NF-kappaB p(65) were inhibited by 5-Aza-Dc and ginseng treatment. This study illustrated that retrotransposon hypermethylation and oxidative stress were evident in the glucose-induced ECs and T1DM along with hypermethylation of the FN1, VEGFa and EDN1 genes. The study also demonstrated the association between hypermethylation of these retrotransposons and oxidative stress in diabetes.