Protein affects gene expression and prevents lipid accumulation in the liver in mice

Obesity and associated increased prevalence of non-alcoholic fatty liver (NAFLD) disease is suggested to be positively modulated by a high protein (HP) diet in humans and rodents. The aim was to detect mechanisms by which a HP diet prevents hepatic lipid accumulation by means of transcriptomics. To study the acute and long term effect of a high protein ingestion on hepatic lipid accumulation under both low and high fat (HF) conditions, mice were fed combinations of high (35%) or low (10%) fat and high (50%) or normal (15%) protein diets for 1 or 12 weeks. Body composition, liver fat, VLDL production rate and gene expression were investigated. Differences in metabolic processes and functions in the liver were identified using gene set enrichment analysis on microarray data. Mice fed the HP diets developed less adiposity and decreased hepatic lipid accumulation due a combination of induced processes mainly involved in protein catabolism such as transamination, TCA cycle and oxidative phosphorylation. Feeding a HP diet can successfully prevent the development of NAFLD by using ingested energy for oxidation instead of storage. Wild type mice were fed combinations of high (35%) or low (10%) fat and high (50%) or normal (15%) protein diets for 1 or 12 weeks. After the diet intervention period, the animals were killed and liver tissue was removed. Total RNA was isolated, pooled and subjected to gene expression profiling.