BioProject

Fast food diet consumption and sedentary life style leads to energy excess, which elevates risks for obesity, metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), and cancer. More...

Fast food diet consumption and sedentary life style leads to energy excess, which elevates risks for obesity, metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), and cancer. Exercise training conveys many health benefits in populations with or without these chronic conditions. Diet and exercise regulate gene expression by mediating epigenetic mechanisms globally and at select loci in an array of human tissues, however, such effects are less well documented in liver tissue. To dissect the epigenetic consequences of diet and exercise in liver, we measured DNA methylation using reduced representation bisulfite sequencing (RRBS) and transcriptome using RNA-seq in mice maintained on a fast food diet with sedentary lifestyle (FFC) or exercise (FFE) compared to control diet with (NCE) and without exercise (NCC). Our analyses demonstrate genome-wide differential DNA methylation at key regulatory regions, including different classes of promoters and enhancers, and differential regulation of gene clusters in each condition group. FFE gene expression is most differentially regulated, with enrichment of carbohydrate/lipid metabolic pathways and skeletal muscle development in altered gene sets. Through evaluation of putative protective effects of exercise on diet-induced DNA methylation and gene expression, we show that hypermethylation is effectively prevented, especially at promoters and enhancers, and hypomethylation is partially attenuated. We assessed diet-induced DNA methylation changes associated with cancer-related epigenetic modifications and identified significant increases at liver-specific enhancers in FFC and FFE, suggesting a repressive effect on the epigenomic signature specifying liver identity. Gaining methylation at a subset of gene promoters was associated with inhibition of tissue development and promotion of carcinogenic process. Taken together, our study demonstrates large-scale diet- and exercise-induced effects on the epigenetic landscape, emphasizing the functional relevance of epigenetic mechanisms as an interface between life-style modifications and phenotypic alterations. Overall design: 2-3 replicates was conducted with RRBS, 3- 6 replicates were pooled for RNA-seq. Less...