title: A systems approach implicates nuclear receptor targeting in the Atp7b(-/-) mouse model of Wilson's disease.
abstract: Wilson's disease (WD) is an inherited disorder of copper metabolism characterized by liver disease and/or neurologic and psychiatric pathology. The disease is a result of mutation in ATP7B, which encodes the ATP7B copper transporting ATPase. Loss of copper transport function by ATP7B results in copper accumulation primarily in the liver, but also in other organs including the brain. Studies in the Atp7b(-/-) mouse model of WD revealed specific transcript and metabolic changes that precede development of liver pathology, most notably downregulation of transcripts in the cholesterol biosynthetic pathway. In order to gain insight into the molecular mechanisms of transcriptomic and metabolic changes, we used a systems approach analysing the pre-symptomatic hepatic nuclear proteome and liver metabolites. We found that ligand-activated nuclear receptors FXR/NR1H4 and GR/NR3C1 and nuclear receptor interacting partners are less abundant in Atp7b(-/-) hepatocyte nuclei, while DNA repair machinery and the nucleus-localized glutathione peroxidase, SelH, are more abundant. Analysis of metabolites revealed an increase in polyol sugar alcohols, indicating a change in osmotic potential that precedes hepatocyte swelling observed later in disease. This work is the first application of quantitative Multidimensional Protein Identification Technology (MuDPIT) to a model of WD to investigate protein-level mechanisms of WD pathology. The systems approach using "shotgun" proteomics and metabolomics in the context of previous transcriptomic data reveals molecular-level mechanisms of WD development and facilitates targeted analysis of hepatocellular copper toxicity.
authors.affiliation: Dept. Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Wilmarth
authors.forename: Kristopher K
authors.initials: KK
authors.lastname: Short
authors.forename: Oliver
authors.initials: O
authors.lastname: Fiehn
authors.forename: Svetlana
authors.initials: S
authors.lastname: Lutsenko
authors.forename: Larry L
authors.initials: LL
authors.lastname: David
authors.forename: Jason L
authors.initials: JL
authors.lastname: Burkhead
mesh_terms: D000251:Adenosine Triphosphatases / Q000172:deficiency* / Q000378:metabolism; D000818:Animals; D027682:Cation Transport Proteins / Q000172:deficiency* / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D000073840:Copper-Transporting ATPases; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000235:genetics; D053263:Gene Regulatory Networks / Q000235:genetics; D005938:Glucocorticoids / Q000097:blood; D006527:Hepatolenticular Degeneration / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D050356:Lipid Metabolism / Q000235:genetics; D055442:Metabolome; D051379:Mice; D009997:Osmotic Pressure; D018384:Oxidative Stress / Q000235:genetics; D020543:Proteome / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D049490:Systems Biology / Q000379:methods*; D059467:Transcriptome / Q000235:genetics; D000099150:Receptor, Farnesoid X-Activated
chemical_list: D000251:Adenosine Triphosphatases; D027682:Cation Transport Proteins; D003300:Copper; D000073840:Copper-Transporting ATPases; D005938:Glucocorticoids; D020543:Proteome; D018160:Receptors, Cytoplasmic and Nuclear; D011965:Receptors, Glucocorticoid; D000099150:Receptor, Farnesoid X-Activated; C486201:Atp7a protein, mouse; C575863:NR3C1 protein, mouse