Overexpression of Peroxiredoxin 6 Does Not Prevent Ethanol-Mediated Oxidative Stress and May Play a Role in Hepatic Lipid Accumulation
- Departments of Pharmaceutical Sciences (J.R.R., D.R.P.) and Pathology (D.J.O.), University of Colorado, Denver, Colorado; and Institute for Environmental Medicine, The University of Pennsylvania, Philadelphia, Pennsylvania (A.B.F.)
- Address correspondence to:
Dr. Dennis R. Petersen, School of Pharmacy C238-P15, Research Bldg. 2, 12700 E. 19th Ave., P.O. Box 6511, Aurora, CO 80045. E-mail: dennis.petersen{at}ucdenver.edu
Abstract
Oxidative stress is implicated in the etiology of many diseases, including alcoholic liver disease (ALD). Peroxiredoxin 6 is a cytosolic peroxidase that has been demonstrated to protect various tissues, such as skin, lung, and cardiac muscle, against acute oxidative insults. Consequently, peroxiredoxin 6 was hypothesized to also protect the liver from oxidative stress generated during the process of chronic ethanol ingestion. To test this, wild-type peroxiredoxin 6 knockout mice (KO), and transgenic peroxiredoxin 6 overexpressing mice (TG) were fed an ethanol-containing diet. Various biomarkers of ALD were assessed, along with the effects of chronic ethanol consumption on the antioxidant defenses. After 9 weeks of ethanol consumption, all backgrounds exhibited elevations of plasma alanine aminotransferase activity, hepatosteatosis, CYP2E1 induction, and lipid peroxidation; however, hepatic triglyceride accumulation seemed to be exacerbated in ethanol-fed TG mice. Differences in antioxidant protein expression and activity in response to chronic ethanol consumption were also observed. Examples include significant inductions of catalase and glutathione transferase activity in ethanol-fed KO and TG mice, along with elevated levels of glutathione peroxidase activity. These alterations in antioxidant defenses could be attributed to either compensatory responses due to the genetic manipulations or ethanol-mediated responses. In conclusion, both ethanol-fed KO and ethanol-fed TG mice developed early stage ALD and peroxiredoxin 6 may play a role in ethanol-mediated hepatic lipid accumulation.
Footnotes
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The work was supported in part by the National Institutes of Health National Institute of Alcohol Abuse and Alcoholism [Grants R37-AA09300, F31-AA016710] (to D.R.P., and to J.R.R., respectively); and by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant 074487] (to D.R.P.).
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.109.152983.
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ABBREVIATIONS: ALD, alcoholic liver disease; Prx, peroxiredoxin; KO, Prx6(-/-) knockout mice; TG, Prx6 transgenic mice; ALT, alanine aminotransferase; NF-κB, nuclear factor-κB; GCLC, glutamate-cysteine ligase catalytic; GST, glutathione transferase; TBARS, thiobarbituric acid-reactive substances; HO, heme oxygenase; 4HNE, 4-hydroxynonenal; GSH, glutathione; SOD, superoxide dismutase; GPx, glutathione peroxidase; Nrf, NF-E2-related factor; WT, wild type.
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- Received March 2, 2009.
- Accepted April 21, 2009.
- The American Society for Pharmacology and Experimental Therapeutics
