title: Severe dysfunction of respiratory chain and cholesterol metabolism in Atp7b(-/-) mice as a model for Wilson disease.
abstract: Wilson disease (WD) is caused by mutations of the WD gene ATP7B resulting in copper accumulation in different tissues. WD patients display hepatic and neurological disease with yet poorly understood pathomechanisms. Therefore, we studied age-dependent (3, 6, 47weeks) biochemical and bioenergetical changes in Atp7b(-/-) mice focusing on liver and brain. Mutant mice showed strongly elevated copper and iron levels. Age-dependently decreasing hepatic reduced glutathione levels along with increasing oxidized to reduced glutathione ratios in liver and brain of 47weeks old mice as well as elevated hepatic and cerebral superoxide dismutase activities in 3weeks old mutant mice highlighted oxidative stress in the investigated tissues. We could not find evidence that amino acid metabolism or beta-oxidation is impaired by deficiency of ATP7B. In contrast, sterol metabolism was severely dysregulated. In brains of 3week old mice cholesterol, 8-dehydrocholesterol, desmosterol, 7-dehydrocholesterol, and lathosterol were all highly increased. These changes reversed age-dependently resulting in reduced levels of all previously increased sterol metabolites in 47weeks old mice. A similar pattern of sterol metabolite changes was found in hepatic tissue, though less pronounced. Moreover, mitochondrial energy production was severely affected. Respiratory chain complex I activity was increased in liver and brain of mutant mice, whereas complex II, III, and IV activities were reduced. In addition, aconitase activity was diminished in brains of Atp7b(-/-) mice. Summarizing, our study reveals oxidative stress along with severe dysfunction of mitochondrial energy production and of sterol metabolism in Atp7b(-/-) mice shedding new light on the pathogenesis of WD.
authors.affiliation: Department of Pediatrics, University Hospital, Heidelberg, Germany. sven.sauer@med.uni-heidelberg.de
authors.forename: Sven W
authors.initials: SW
authors.lastname: Sauer
authors.forename: Uta
authors.initials: U
authors.lastname: Merle
authors.forename: Silvana
authors.initials: S
authors.lastname: Opp
authors.forename: Dorothea
authors.initials: D
authors.lastname: Haas
authors.forename: Georg F
authors.initials: GF
authors.lastname: Hoffmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Stremmel
authors.forename: Jürgen G
authors.initials: JG
authors.lastname: Okun
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000235:genetics*; D000409:Alanine / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000378:metabolism; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics*; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D000073840:Copper-Transporting ATPases; D004195:Disease Models, Animal; D004579:Electron Transport; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism; D055786:Gene Knockout Techniques; D005978:Glutathione / Q000378:metabolism; D006527:Hepatolenticular Degeneration / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: C486201:Atp7a protein, mouse; D027682:Cation Transport Proteins; D045222:Electron Transport Chain Complex Proteins; C116917:acylcarnitine; D003300:Copper; D002784:Cholesterol; D013482:Superoxide Dismutase; D000251:Adenosine Triphosphatases; D000154:Aconitate Hydratase; D000073840:Copper-Transporting ATPases; D005978:Glutathione; D000409:Alanine; D002331:Carnitine