The mechanisms of liver injury in alcoholic liver disease in rats fed ethanol are numerous. One of these mechanisms involves free radical generation when ethanol is metabolized by CYP2E1 in the liver. The free radicals produced lead to the increase in formation of products of lipid peroxidation including 4 hydroxynonenal (4HNE). 4HNE forms adducts with various proteins including some of the subunits of the 26s proteasome. Chronic ethanol ingestion also induces post translational modification of the proteasomes such as hyperphosphorylation of the subunits. Therefore, we hypothesize that when ethanol is consumed continuously for a prolonged period, CYP2E1 is induced and this generates a free radical attack on lipids. The by- products alter the proteasomal subunits to cause loss of catalytic function. The loss of proteolysis by the proteasome leads to the accumulation of altered proteins in the cells.
Specific Aim 1 : To determine the molecular post translational modifications of the 20s and 19s proteasome subunits from the liver of rats-fed ethanol intragastrically for 1 month (in vivo model). Hypothesis: 4HNE adducts and phosphorylation on specific sites on subunits of the proteasome accounts for the loss of catalytic activity in chronic ethanol fed rats.
Specific Aim 2 : To determine [the molecular mechanisms of proteasome inhibition by alcohol in vitro using the HepG2 CYP2E1 transduced cell line].
Specific Aim 3 : To determine [by microarray analysis, the changes in gene expression associated with ethanol inhibition of the proteasome, comparing the rat fed ethanol in vivo with the HepG2 model in vitro]. If this approach determines [how] ethanol-induces proteasomal inhibition, then a new mechanism of ethanol-induced liver injury will have been established which could provide a target for therapeutic intervention.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA008116-17
Application #
7845559
Study Section
Hepatobiliary Pathophysiology Study Section (HBPP)
Program Officer
Gao, Peter
Project Start
1990-11-01
Project End
2012-05-31
Budget Start
2010-06-01
Budget End
2012-05-31
Support Year
17
Fiscal Year
2010
Total Cost
$313,574
Indirect Cost
Name
La Biomed Research Institute/ Harbor UCLA Medical Center
Department
Type
DUNS #
069926962
City
Torrance
State
CA
Country
United States
Zip Code
90502
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Oliva, Joan; French, Samuel W; Li, Jun et al. (2012) Proteasome inhibitor treatment reduced fatty acid, triacylglycerol and cholesterol synthesis. Exp Mol Pathol 93:26-34
Oliva, Joan; Zhong, Jin; Buslon, Virgil S et al. (2012) The effect of SAMe and betaine on Hepa 1-6, C34 and E47 liver cell survival in vitro. Exp Mol Pathol 92:126-30
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French, B A; Oliva, J; Bardag-Gorce, F et al. (2011) The immunoproteasome in steatohepatitis: its role in Mallory-Denk body formation. Exp Mol Pathol 90:252-6
Bardag-Gorce, Fawzia; French, Samuel W (2011) Delta-aminolevulinic dehydratase is a proteasome interacting protein. Exp Mol Pathol 91:485-9
Qing, Xin; French, Babara A; Oliva, Joan et al. (2011) Increased expression of FAT10 in colon benign, premalignant and malignant epithelial neoplasms. Exp Mol Pathol 90:51-4

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