Comprehensive assessment of oxidatively induced modifications of DNA in a rat model of human Wilson's disease

Yang Yu, Candace R. Guerrero, Shuo Liu, Nicholas J. Amato, Yogeshwar Sharma, Sanjeev Gupta, Yinsheng Wang

Research output: Contribution to journalArticle

24 Scopus citations

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,N6-etheno-2'-deoxyadenosine (εdA) and 1, N2-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 Cu2+ 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.

Original languageEnglish (US)
Pages (from-to)810-817
Number of pages8
JournalMolecular and Cellular Proteomics
Volume15
Issue number3
DOIs
StatePublished - Mar 2016

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Molecular Biology

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