Proteomic profiling of liver tissue from the mdx-4cv mouse model of Duchenne muscular dystrophy

Background: Duchenne muscular dystrophy is a highly complex multi-system disease caused by primary abnormalities in the membrane cytoskeletal protein dystrophin. Besides progressive skeletal muscle degeneration, this neuromuscular disorder is also associated with pathophysiological perturbations in many other organs including the liver. To determine potential proteome-wide alterations in liver tissue, we have used a comparative and mass spectrometry-based approach to study the dystrophic mdx-4cv mouse model of dystrophinopathy. Methods: The comparative proteomic profling of mdx-4cv versus wild type liver extracts was carried out with an Orbitrap Fusion Tribrid mass spectrometer. The distribution of identifed liver proteins within protein families and potential protein interaction patterns were analysed by systems bioinformatics. Key fndings on fatty acid binding proteins were confrmed by immunoblot analysis and immunofuorescence microscopy. Results: The proteomic analysis revealed changes in a variety of protein families, afecting especially fatty acid, carbohydrate and amino acid metabolism, biotransformation, the cellular stress response and ion handling in the mdx-4cv liver. Drastically increased protein species were identifed as fatty acid binding protein FABP5, ferritin and calumenin. Decreased liver proteins included phosphoglycerate kinase, apolipoprotein and perilipin. The drastic change in FABP5 was independently verifed by immunoblotting and immunofuorescence microscopy. Conclusions: The proteomic results presented here indicate that the intricate and multifaceted pathogenesis of the mdx-4cv model of dystrophinopathy is associated with secondary alterations in the liver afecting especially fatty acid transportation. Since FABP5 levels were also shown to be elevated in serum from dystrophic mice, this protein might\ud be a useful indicator for monitoring liver changes in X-linked muscular dystrophy