Altered DNA methylation of glycolytic and lipogenic genes in liver from obese and type 2 diabetic patients [transcriptome analysis]

Type 2 diabetes is a complex disease associated with many underlying pathomechanisms. Epigenetic regulation of gene expression by DNA methylation has become increasingly recognized as an important component in the etiology of type 2 diabetes. We performed genome-wide methylome and transcriptome analysis in liver from severely obese patients with or without type 2 diabetes to discover aberrant pathways underlying the development of insulin resistance. We identified hypomethylation of five key genes involved in hepatic glycolysis, de novo lipogenesis and insulin resistance with concomitant increased mRNA expression and protein content. The CpG-site within the ATF-motif was hypomethylated in four of these genes in liver of non-diabetic and type 2 diabetic obese patients, suggesting epigenetic regulation of transcription by altered ATF-DNA binding. In conclusion, severely obese non-diabetic and type 2 diabetic patients have distinct alterations in the hepatic methylome and transcriptome and genes controlling glucose and lipid metabolism are hypomethylated at a regulatory site. Thus, obesity may epigenetically reprogram the liver towards increased lipid production and exacerbate the development of insulin resistance.

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Kirchner H, Sinha I, Gao H, Ruby MA, Schönke M, Lindvall JM, Barrès R, Krook A, Näslund E, Dahlman-Wright K, Zierath JR