High fat diet-induced modifications in membrane lipid and mitochondrial-membrane protein signatures precede the development of hepatic insulin resistance in mice

In this survey we effectively combined transcriptomics, proteomics and targeted-metabolomics to analyse the temporal relationship of alterations in liver preceding and accompanying the development of HFD-mediated hepatic insulin resistance. To assess HFD-mediated alterations in physiological parameters, insulin sensitivity, and molecular adaptations in liver male C3HeB/FeJ mice treated with a high-fat diet (HFD) for 7, 14, or 21 days and compared to age- matched controls fed low-fat diet (LFD). Data indicate early systemic increases in pro-inflammatory signals, in hepatic DAG but not hepatic TAG concentrations prior to development of hepatic insulin resistance. We propose a hypothesis via which a HFD-mediated increase in the hepatic long-chain acyl-carnitine moiety in liver alters mitochondrial membrane physiology and beta-oxidation rates, thereby contributing to oxidative stress and the development of insulin resistance in liver. Alterations in the enrichment of respiratory chain complex proteins, substrate transporters, VDACs, and long-chain carnitines in mitochondrial membranes likely affect mitochondrial membrane topology, membrane dynamics (fission and fusion) and bioenergetics as well as the cross-talk between the mitochondria and other cellular compartments. In conclusion, we emphasize a tight association between HFD-induced early modifications in the organisation of mitochondrial membranes paving the road for hepatic insulin resistance. We performed gene expression microarray analysis on liver from C3HeB/FeJ (C3H) males during 7, 14 or 21 days HFD challenge.