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Glutathione-dependent reductive stress triggers mitochondrial oxidation and cytotoxicity. FASEB J 2012 Apr;26(4):1442-51

Date

12/29/2011

Pubmed ID

22202674

Pubmed Central ID

PMC3316899

DOI

10.1096/fj.11-199869

Scopus ID

2-s2.0-84860904314   93 Citations

Abstract

To investigate the effects of the predominant nonprotein thiol, glutathione (GSH), on redox homeostasis, we employed complementary pharmacological and genetic strategies to determine the consequences of both loss- and gain-of-function GSH content in vitro. We monitored the redox events in the cytosol and mitochondria using reduction-oxidation sensitive green fluorescent protein (roGFP) probes and the level of reduced/oxidized thioredoxins (Trxs). Either H(2)O(2) or the Trx reductase inhibitor 1-chloro-2,4-dinitrobenzene (DNCB), in embryonic rat heart (H9c2) cells, evoked 8 or 50 mV more oxidizing glutathione redox potential, E(hc) (GSSG/2GSH), respectively. In contrast, N-acetyl-L-cysteine (NAC) treatment in H9c2 cells, or overexpression of either the glutamate cysteine ligase (GCL) catalytic subunit (GCLC) or GCL modifier subunit (GCLM) in human embryonic kidney 293 T (HEK293T) cells, led to 3- to 4-fold increase of GSH and caused 7 or 12 mV more reducing E(hc), respectively. This condition paradoxically increased the level of mitochondrial oxidation, as demonstrated by redox shifts in mitochondrial roGFP and Trx2. Lastly, either NAC treatment (EC(50) 4 mM) or either GCLC or GCLM overexpression exhibited increased cytotoxicity and the susceptibility to the more reducing milieu was achieved at decreased levels of ROS. Taken together, our findings reveal a novel mechanism by which GSH-dependent reductive stress triggers mitochondrial oxidation and cytotoxicity.

Author List

Zhang H, Limphong P, Pieper J, Liu Q, Rodesch CK, Christians E, Benjamin IJ

Author

Ivor J. Benjamin MD Center Director, Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Acetylcysteine
Animals
Cytosol
Dinitrochlorobenzene
Free Radical Scavengers
Glutamate-Cysteine Ligase
Glutathione
Glutathione Disulfide
Green Fluorescent Proteins
HEK293 Cells
Heart
Homeostasis
Humans
Hydrogen Peroxide
Indicators and Reagents
Mitochondria
Myocardium
Oxidants
Oxidation-Reduction
Oxidative Stress
Protein Subunits
Rats
Reactive Oxygen Species
Thioredoxins
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a