title: Comprehensive Assessment of Oxidatively Induced Modifications of DNA in a Rat Model of Human Wilson's Disease.
abstract: Defective copper excretion from hepatocytes in Wilson's disease causes accumulation of copper ions with increased generation of reactive oxygen species via the Fenton-type reaction. Here we developed a nanoflow liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry coupled with the isotope-dilution method for the simultaneous quantification of oxidatively induced DNA modifications. This method enabled measurement, in microgram quantities of DNA, of four oxidative stress-induced lesions, including direct ROS-induced purine cyclonucleosides (cPus) and two exocyclic adducts induced by byproducts of lipid peroxidation, i.e. 1,N(6)-etheno-2'-deoxyadenosine (εdA) and 1,N(2)-etheno-2'-deoxyguanosine (εdG). Analysis of liver tissues of Long-Evans Cinnamon rats, which constitute an animal model of human Wilson's disease, and their healthy counterparts [i.e. Long-Evans Agouti rats] showed significantly higher levels of all four DNA lesions in Long-Evans Cinnamon than Long-Evans Agouti rats. Moreover, cPus were present at much higher levels than εdA and εdG lesions. In contrast, the level of 5-hydroxymethyl-2'-deoxycytidine (5-HmdC), an oxidation product of 5-methyl-2'-deoxycytidine (5-mdC), was markedly lower in the liver tissues of Long-Evans Cinnamon than Long-Evans Agouti rats, though no differences were observed for the levels of 5-mdC. In vitro biochemical assay showed that Cu(2+) ions could directly inhibit the activity of Tet enzymes. Together, these results suggest that aberrant copper accumulation may perturb genomic stability by elevating oxidatively induced DNA lesions, and by altering epigenetic pathways of gene regulation.
authors.affiliation: From the ‡Environmental Toxicology Graduate Program and.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: §Department of Chemistry, University of California, Riverside, California 92521;
authors.forename: Candace R
authors.initials: CR
authors.lastname: Guerrero
authors.affiliation: From the ‡Environmental Toxicology Graduate Program and.
authors.forename: Shuo
authors.initials: S
authors.lastname: Liu
authors.affiliation: §Department of Chemistry, University of California, Riverside, California 92521;
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Amato
authors.affiliation: ¶Department of Medicine and.
authors.forename: Yogeshwar
authors.initials: Y
authors.lastname: Sharma
authors.affiliation: ¶Department of Medicine and ‖Department of Pathology, **Marion Bessin Liver Research Center, Diabetes Center, Cancer Center, and Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, Albert Einstein College of Medicine, Bronx, New York 10461.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Gupta
authors.affiliation: From the ‡Environmental Toxicology Graduate Program and §Department of Chemistry, University of California, Riverside, California 92521; Yinsheng.Wang@ucr.edu.
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D003300:Copper / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000378:metabolism; D004195:Disease Models, Animal; D044127:Epigenesis, Genetic; D042822:Genomic Instability; D006527:Hepatolenticular Degeneration / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism; D036103:Nanotechnology; D010084:Oxidation-Reduction; D051381:Rats; D020318:Rats, Long-Evans; D017382:Reactive Oxygen Species / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C540838:5-hydroxymethyl-2'-deoxycytidine; D017382:Reactive Oxygen Species; D003841:Deoxycytidine; D003300:Copper; D004247:DNA