Expression data from mouse liver after chow and high-fat diet feeding

Epigenetic changes are present in multiple tissues of rodents and subjects suffering from obesity and type 2 diabetes. Especially, genes that are important for glucose and lipid metabolism seem to be at least co-regulated by DNA methylation. We aimed to investigate if altered DNA methylation in liver of mice can be induced by feeding a high-fat diet and if these changes can be reverted by weight loss. We used microarrays to measure the hepatic gene expression pattern in chow and high-fat diet (HFD) fed mice to identify dysregulated pathways which contribute to diet-induced obesity and insulin resistance. DNA methylation was measured of candidate genes to evaluate this as potential regulatory mechanism. Liver tissue of HFD and chow fed mice was collected after one week and twelve weeks of feeding for RNA extraction and hybridization on Affymetrix microarrays. This longitudinal design allows us to preselect dysregulated pathways in the manifestation of obesity and insulin resistance. Thereby, identified candidate genes are used for a close tracking of the expression pattern over a time course of 12 weeks to identify possible metabolic switches in liver and to assess whether this is causal or consequential of HFD feeding. DNA methylation was measured at selected potential regulatory CpG-sites in order to evaluate this mechanism as key regulator of altered gene expression.