title: Differential metabolomics reveals ophthalmic acid as an oxidative stress biomarker indicating hepatic glutathione consumption.
abstract: Metabolomics is an emerging tool that can be used to gain insights into cellular and physiological responses. Here we present a metabolome differential display method based on capillary electrophoresis time-of-flight mass spectrometry to profile liver metabolites following acetaminophen-induced hepatotoxicity. We globally detected 1,859 peaks in mouse liver extracts and highlighted multiple changes in metabolite levels, including an activation of the ophthalmate biosynthesis pathway. We confirmed that ophthalmate was synthesized from 2-aminobutyrate through consecutive reactions with gamma-glutamylcysteine and glutathione synthetase. Changes in ophthalmate level in mouse serum and liver extracts were closely correlated and ophthalmate levels increased significantly in conjunction with glutathione consumption. Overall, our results provide a broad picture of hepatic metabolite changes following acetaminophen treatment. In addition, we specifically found that serum ophthalmate is a sensitive indicator of hepatic GSH depletion, and may be a new biomarker for oxidative stress. Our method can thus pinpoint specific metabolite changes and provide insights into the perturbation of metabolic pathways on a large scale and serve as a powerful new tool for discovering low molecular weight biomarkers.
authors.affiliation: Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan. soga@sfc.keio.ac.jp
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Soga
authors.forename: Richard
authors.initials: R
authors.lastname: Baran
authors.forename: Makoto
authors.initials: M
authors.lastname: Suematsu
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ueno
authors.forename: Satsuki
authors.initials: S
authors.lastname: Ikeda
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Sakurakawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kakazu
authors.forename: Takamasa
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Martin
authors.initials: M
authors.lastname: Robert
authors.forename: Takaaki
authors.initials: T
authors.lastname: Nishioka
authors.forename: Masaru
authors.initials: M
authors.lastname: Tomita
mesh_terms: D000818:Animals; D004151:Dipeptides / Q000378:metabolism; D019075:Electrophoresis, Capillary; D020869:Gene Expression Profiling; D005978:Glutathione / Q000378:metabolism*; D005981:Glutathione Synthase / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008660:Metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D009842:Oligopeptides / Q000378:metabolism*; D018384:Oxidative Stress
chemical_list: D004151:Dipeptides; D009842:Oligopeptides; C016632:ophthalmic acid; D005981:Glutathione Synthase; D005978:Glutathione; C017341:gamma-glutamylcysteine