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Glutathione and antioxidant enzymes serve complementary roles in protecting activated hepatic stellate cells against hydrogen peroxide-induced cell death

Dunning, S., Rehman, A. U., Tiebosch, M. H., Hannivoort, R. A., Haijer, F. W., Woudenberg, J., van den Heuvel, F. A. J., Buist-Homan, M., Faber, K. N. & Moshage, H., Dec-2013, In : Biochimica et biophysica acta-Molecular basis of disease. 1832, 12, p. 2027-2034 8 p.

Research output: Contribution to journalArticleAcademicpeer-review

Background: In chronic liver disease, hepatic stellate cells (HSCs) are activated, highly proliferative and produce excessive amounts of extracellular matrix, leading to liver fibrosis. Elevated levels of toxic reactive oxygen species (ROS) produced during chronic liver injury have been implicated in this activation process. Therefore, activated hepatic stellate cells need to harbor highly effective anti-oxidants to protect against the toxic effects of ROS.

Aim: To investigate the protective mechanisms of activated HSCs against ROS-induced toxicity.

Methods: Culture-activated rat HSCs were exposed to hydrogen peroxide. Necrosis and apoptosis were determined by Sytox Green or acridine orange staining, respectively. The hydrogen peroxide detoxifying enzymes catalase and glutathione-pefoxidase (GPx) were inhibited using 3-amino-1,2,4-triazole and mercaptosuccinic acid, respectively. The anti-oxidant glutathione was depleted by L-buthionine-sulfoximine and repleted with the GSH-analogue GSH-monoethylester (GSH-MEE).

Results: Upon activation, HSCs increase their cellular glutathione content and GPx expression, while MnSOD (both at mRNA and protein level) and catalase (at the protein level, but not at the mRNA level) decreased. Hydrogen peroxide did not induce cell death in activated HSCs. Glutathione depletion increased the sensitivity of HSCs to hydrogen peroxide, resulting in 35% and 75% necrotic cells at 0.2 and 1 mmol/L hydrogen peroxide, respectively. The sensitizing effect was abolished by GSH-MEE. Inhibition of catalase or GPx significantly increased hydrogen peroxide-induced apoptosis, which was not reversed by GSH-MEE.

Conclusion: Activated HSCs have increased ROS-detoxifying capacity compared to quiescent HSCs. Glutathione levels increase during HSC activation and protect against ROS-induced necrosis, whereas hydrogen peroxide-detoxifying enzymes protect against apoptotic cell death. (C) 2013 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)2027-2034
Number of pages8
JournalBiochimica et biophysica acta-Molecular basis of disease
Volume1832
Issue number12
Publication statusPublished - Dec-2013

    Keywords

  • Oxidative stress, Glutathione peroxidase, Catalase, Superoxide dismutase, Cell death, GAMMA-GLUTAMYLCYSTEINE SYNTHETASE, MANGANESE SUPEROXIDE-DISMUTASE, OXIDATIVE STRESS, ANTIFIBROGENIC PROTEIN, DEFICIENT MICE, LIVER-INJURY, PROLIFERATION, MECHANISMS, EXPRESSION, MOUSE

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