Pharmaceutical Sciences Faculty Publications

Title

Increased Oxidation and Degradation of Cytosolic Proteins in Alcohol-Exposed Mouse Liver and Hepatoma Cells

Document Type

Article

Publication Date

2-1-2006

Journal Title

Proteomics

ISSN

1615-9853

Volume

6

Issue

4

First Page

1250

Last Page

1260

DOI

10.1002/pmic.200500447

PubMed ID

16408314

PubMed Central® ID

PMC1368983

Abstract

We recently developed a sensitive method using biotin-N-maleimide (biotin-NM) as a probe to positively identify oxidized mitochondrial proteins. In this study, biotin-NM was used to identify oxidized cytosolic proteins in alcohol-fed mouse livers. Alcohol treatment for 6 wk elevated the levels of CYP2E1 and nitrotyrosine, a marker of oxidative stress. Markedly increased levels of oxidized proteins were detected in alcohol-fed mouse livers compared to pair-fed controls. The biotin-NM-labeled oxidized proteins from alcohol-exposed mouse livers were subsequently purified with streptavidin-agarose and resolved on 2-DE. More than 90 silver-stained protein spots that displayed differential intensities on 2-D gels were identified by MS. Peptide sequence analysis revealed that many enzymes or proteins involved in stress response, chaperone activity, intermediary metabolism, and antioxidant defense systems such as peroxiredoxin were oxidized after alcohol treatment. Smaller fragments of many proteins were repeatedly detected only in alcohol-fed mice, indicating that many oxidized proteins after alcohol exposure were degraded. Immunoblot results showed that the level of oxidized peroxiredoxin (inactivated) was markedly increased in the alcohol-exposed mouse livers and ethanol-sensitive hepatoma cells compared to the corresponding controls. Our results may explain the underlying mechanism for cellular dysfunction and increased susceptibility to other toxic agents following alcohol-mediated oxidative stress.

Keywords

Bacterial proteins, biomarkers, tumor, biotin, carcinoma, hepatocellular, central nervous system depressants, computational biology, cytosol, electrophoresis, gel, ethanol, liver neoplasms, oxidation-reduction, peroxiredoxins, sepharose, spectrometry, mass, tyrosine

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