Additive effects of mitochondrion-targeted cytochrome CYP2E1 and alcohol toxicity on cytochrome c oxidase function and stability of respirosome complexes. J Biol Chem 2012 May 04;287(19):15284-97
Date
03/08/2012Pubmed ID
22396533Pubmed Central ID
PMC3346148DOI
10.1074/jbc.M111.314062Scopus ID
2-s2.0-84860869284 (requires institutional sign-in at Scopus site) 28 CitationsAbstract
Alcohol treatment induces oxidative stress by a combination of increased production of partially reduced oxygen species and decreased cellular antioxidant pool, including GSH. Recently, we showed that mitochondrion-targeted CYP2E1 augments alcohol-mediated toxicity, causing an increase in reactive oxygen species production and oxidative stress. Here, we show that cytochrome c oxidase (CcO), the terminal oxidase of the mitochondrial respiratory chain, is a critical target of CYP2E1-mediated alcohol toxicity. COS-7 and Hep G2 cell lines expressing predominantly mitochondrion-targeted (Mt(++)) CYP2E1 and livers from alcohol-treated rats showed loss of CcO activity and increased protein carbonylation, which was accompanied by a decline in the steady state levels of subunits I, IVI1, and Vb of the CcO complex. This was also accompanied by reduced mitochondrial DNA content and reduced mitochondrial mRNA. These changes were more prominent in Mt(++) cells in comparison with wild type (WT) CYP2E1-expressing or ER(+) (mostly microsome-targeted) cells. In addition, mitochondrion-specific antioxidants, ubiquinol conjugated to triphenyl phosphonium, triphenylphosphonium conjugated carboxyl proxyl, and the CYP2E1 inhibitor diallyl sulfide prevented the loss of CcO activity and the CcO subunits, most likely through reduced oxidative damage to the enzyme complex. Our results suggest that damage to CcO and dissociation of respirosome complexes are critical factors in alcohol-induced toxicity, which is augmented by mitochondrion-targeted CYP2E1. We propose that CcO is one of the direct and immediate targets of alcohol-induced toxicity causing respiratory dysfunction.
Author List
Bansal S, Srinivasan S, Anandasadagopan S, Chowdhury AR, Selvaraj V, Kalyanaraman B, Joseph J, Avadhani NGAuthor
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsAntioxidants
COS Cells
Central Nervous System Depressants
Cytochrome P-450 CYP2E1
DNA, Mitochondrial
Electron Transport
Electron Transport Complex IV
Ethanol
Hep G2 Cells
Humans
Immunoblotting
Liver
Microsomes
Mitochondria
Mitochondria, Liver
Mitochondrial Proteins
Oxygen Consumption
Protein Carbonylation
Rats
Rats, Sprague-Dawley
Reactive Oxygen Species
Reverse Transcriptase Polymerase Chain Reaction
Transcription, Genetic