Murine hepatic proteome adaptation to high-fat diets with different contents of saturated fatty acids and linoleic acid : α-linolenic acid polyunsaturated fatty acid ratios

Abstract

Some health disorders, such as obesity and type 2 diabetes, are associated with a poor diet and low quality of the fat in it. The type and duration of the diet have an impact on the liver. This investigation uses the proteomic approach to identify changes in the mouse liver protein profile in adaptation to high-fat diets with different saturated fatty acid contents and linoleic acid (18:2n-6) to α-linolenic acid (18:3n-3) fatty acid ratios. Four groups of male mice were fed different diets: one standard diet and three high-fat diets were investigated. After six months on these diets, the animals were sacrificed for liver dissection. Two-dimensional electrophoresis was used to separate the complex liver protein mixture, which enabled the separation of proteins against a wide, 3–10 range of pH and molecular weights of 15–250 kDa. Protein profiles were analysed in the PDQuest Advanced 8.0.1 program. Differentially expressed spots were identified using matrix-assisted laser desorption/ionisation–time-of-flight tandem mass spectrometry and peptide mass fingerprinting. The levels of identified proteins were validated using Western blotting. Transcript levels were evaluated using a real-time quantitative PCR. The analysis of mouse liver protein profiles enabled the identification of 32 protein spots differing between nutritional groups. A diet high in polyunsaturated fatty acids modulated the levels of liver proteins involved in critical metabolic pathways, including amino acid metabolism, carbohydrate metabolism and cellular response to oxidative stress.