Glutathione-dependent reductive stress triggers mitochondrial oxidation and cytotoxicity. FASEB J 2012 Apr;26(4):1442-51
Date
12/29/2011Pubmed ID
22202674Pubmed Central ID
PMC3316899DOI
10.1096/fj.11-199869Scopus ID
2-s2.0-84860904314 (requires institutional sign-in at Scopus site) 171 CitationsAbstract
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 IJAuthor
Ivor J. Benjamin MD Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AcetylcysteineAnimals
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