title: Quantitative analyses of the hepatic proteome of methylmercury-exposed Atlantic cod (Gadus morhua) suggest oxidative stress-mediated effects on cellular energy metabolism.
abstract: Methylmecury (MeHg) is a widely distributed environmental pollutant with considerable risk to both human health and wildlife. To gain better insight into the underlying mechanisms of MeHg-mediated toxicity, we have used label-free quantitative mass spectrometry to analyze the liver proteome of Atlantic cod (Gadus morhua) exposed in vivo to MeHg (0, 0.5, 2 mg/kg body weight) for 2 weeks.
  
  
  
  Out of a toltal of 1143 proteins quantified, 125 proteins were differentially regulated between MeHg-treated samples and controls. Using various bioinformatics tools, we performed gene ontology, pathway and network enrichment analysis, which indicated that proteins and pathways mainly related to energy metabolism, antioxidant defense, cytoskeleton remodeling, and protein synthesis were regulated in the hepatic proteome after MeHg exposure. Comparison with previous gene expression data strengthened these results, and further supported that MeHg predominantly affects many energy metabolism pathways, presumably through its strong induction of oxidative stress. Some enzymes known to have functionally important oxidation-sensitive cysteine residues in other animals are among the differentially regulated proteins, suggesting their modulations by MeHg-induced oxidative stress. Integrated analysis of the proteomics dataset combined with previous gene expression dataset showed a more pronounced effect of MeHg on amino acid, glucose and fatty acid metabolic pathways, and suggested possible interactions of the cellular energy metabolism and antioxidant defense pathways.
  
  
  
  MeHg disrupts mainly redox homeostasis and energy generating metabolic pathways in cod liver. The energy pathways appear to be modulated through MeHg-induced oxidative stress, possibly mediated by oxidation sensitive enzymes.
authors: Department of Biology, University of Bergen, PO Box 7803, N-5020, Bergen, Norway.
authors: Fekadu
authors: F
authors: Yadetie
authors: Department of Biology, University of Bergen, PO Box 7803, N-5020, Bergen, Norway.
authors: Silje
authors: S
authors: Bjørneklett
authors: Department of Biomedicine, Proteomics Unit (PROBE) at the University of Bergen, Bergen, Norway.
authors: Hilde Kristin
authors: HK
authors: Garberg
authors: Department of Biomedicine, Proteomics Unit (PROBE) at the University of Bergen, Bergen, Norway.
authors: Eystein
authors: E
authors: Oveland
authors: Department of Biomedicine, Proteomics Unit (PROBE) at the University of Bergen, Bergen, Norway.
authors: Frode
authors: F
authors: Berven
authors: Department of Biology, University of Bergen, PO Box 7803, N-5020, Bergen, Norway.
authors: Anders
authors: A
authors: Goksøyr
authors: Department of Biology, University of Bergen, PO Box 7803, N-5020, Bergen, Norway. Odd.Karlsen@uib.no.
authors: Odd André
authors: OA
authors: Karlsen
mesh_terms: D000818:Animals; D015415:Biomarkers; D019295:Computational Biology / Q000379:methods; D004734:Energy Metabolism / Q000187:drug effects*; D048389:Gadus morhua / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D063990:Gene Ontology; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008767:Methylmercury Compounds / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D025941:Protein Interaction Mapping; D060066:Protein Interaction Maps; D020543:Proteome; D040901:Proteomics / Q000379:methods
chemical_list: D015415:Biomarkers; D008767:Methylmercury Compounds; D020543:Proteome