TY - JOUR
T1 - Glutathione and antioxidant enzymes serve complementary roles in protecting activated hepatic stellate cells against hydrogen peroxide-induced cell death
AU - Dunning, Sandra
AU - Rehman, Atta Ur
AU - Tiebosch, Marjolein H.
AU - Hannivoort, Rebekka A.
AU - Haijer, Floris W.
AU - Woudenberg, Jannes
AU - van den Heuvel, Fiona A. J.
AU - Buist-Homan, Manon
AU - Faber, Klaas Nico
AU - Moshage, Han
PY - 2013/12
Y1 - 2013/12
N2 - 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.
AB - 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.
KW - Oxidative stress
KW - Glutathione peroxidase
KW - Catalase
KW - Superoxide dismutase
KW - Cell death
KW - GAMMA-GLUTAMYLCYSTEINE SYNTHETASE
KW - MANGANESE SUPEROXIDE-DISMUTASE
KW - OXIDATIVE STRESS
KW - ANTIFIBROGENIC PROTEIN
KW - DEFICIENT MICE
KW - LIVER-INJURY
KW - PROLIFERATION
KW - MECHANISMS
KW - EXPRESSION
KW - MOUSE
U2 - 10.1016/j.bbadis.2013.07.008
DO - 10.1016/j.bbadis.2013.07.008
M3 - Article
C2 - 23871839
SN - 0925-4439
VL - 1832
SP - 2027
EP - 2034
JO - Biochimica et biophysica acta-Molecular basis of disease
JF - Biochimica et biophysica acta-Molecular basis of disease
IS - 12
ER -