Obesity alone or with type 2 diabetes is associated with tissue specific alterations in DNA methylation and gene expression of PPARGC1A and IGF2

BACKGROUND: Epigenetic modifications of key genes have been linked to the development of aging related diseases, such as type 2 diabetes, with increased DNA methylation of the transcriptional co-activator, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) in islets and skeletal muscle of patients with type 2 diabetes. Here, we examined DNA methylation and gene expression of PPARGC1A and insulin like growth factor-2 (IGF2) in adipose tissue and skeletal muscle of lean and morbidly obese individuals with or without type 2 diabetes. METHODS: Adipose tissue and skeletal muscle biopsies were collected from 24 lean, obese, and obese patients with type 2 diabetes (n=8/group). DNA methylation and gene expression of PPARGC1A and IGF2 were measured using pyrosequencing and quantitative real-time PCR respectively. RESULTS: DNA methylation and expression of both genes varied in a tissue specific manner (P