Alteration of Liver Peroxisomal and Mitochondrial Functionality in the NZO Mouse Model of Metabolic Syndrome.. Mus musculus

Purpose: MetS consist of five risk factors: elevated blood pressure and fasting glucose, visceral obesity, dyslipidemia and hypercholesterinemia. The physiological impact of lipid metabolism indicated as visceral obesity and hepatic lipid accumulation is still under debate. One major cause of disturbed lipid metabolism might be dysfunction of cellular organelles controlling energy homeostasis, i.e. mitochondria and peroxisomes. Experimental design: The New Zealand Obese (NZO) mouse model exhibits a polygenic syndrome of obesity, insulin resistance, triglyceridemia and hypercholesterolemia that resembles human metabolic syndrome. We applied a combinatorial approach of lipidomics with liver transcriptomics, 2D-DIGETM and mass spectroscopy based organelle proteomics of highly purified mitochondria and peroxisomes in male mice, to investigate molecular mechanisms related to the impact of lipid metabolism in the pathophysiology of the metabolic syndrome. Conclusions and clinical relevance: Proteome analyses of liver organelles indicated differences in fatty acid metabolism, oxidative stress and response, mainly influenced by PG-C1α/PPARα mediated pathways. These results were in accordance with serum lipid profiles and elevated organelle functionality. These data emphasize that metabolic syndrome is accompanied with increased mitochondria and peroxisomal activity controlling directly cellular energy homeostasis to cope with dyslipidemia and hypercholesterinemia driven hepatic lipid overflow in developing a fatty liver. Overall design: C57BL/KS (BKS) and NZO mice (littermates) were kept under standadized conditions with regular chow until NZO mice develop the diabetes, obesity and metabolic syndrome (18 weeks of age).