PT  - JOURNAL ARTICLE
AU  - Maxwell Afari Gyamfi
AU  - Lin He
AU  - Samuel William French
AU  - Ivan Damjanov
AU  - Yu-Jui Yvonne Wan
TI  - Hepatocyte Retinoid X Receptor α-Dependent Regulation of Lipid Homeostasis and Inflammatory Cytokine Expression Contributes to Alcohol-Induced Liver Injury
AID  - 10.1124/jpet.107.132258
DP  - 2008 Feb 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 443--453
VI  - 324
IP  - 2
4099  - http://jpet.aspetjournals.org/content/324/2/443.short
4100  - http://jpet.aspetjournals.org/content/324/2/443.full
SO  - J Pharmacol Exp Ther2008 Feb 01; 324
AB  - Hepatocyte retinoid X receptor α (RXRα)-deficient mice are more sensitive to ethanol toxicity than wild-type mice. Because RXRα-mediated pathways are implicated in lipid homeostasis and the inflammatory response, we hypothesized that a compromise in lipid metabolism and associated production of proinflammatory mediators are responsible for the hepatotoxicity observed in ethanol-treated hepatocyte RXRα-deficient mice. Wild-type and hepatocyte RXRα-deficient mice were fed ethanol-containing diets or pair-fed control diets for 6 weeks. After ethanol treatment, serum ALT levels increased significantly (4-fold) in hepatocyte RXRα-deficient mice, but not in the wild-type mice. Hepatic liver fatty acid binding protein (L-FABP) mRNA and protein levels were reduced due to RXRα deficiency. Ethanol induced L-FABP mRNA and protein in wild-type mice and provided protection against nonesterified fatty acid toxicity; however, this effect was absent in the mutant mice. Accordingly, hepatic nonesterified fatty acid level was increased in ethanol-fed mutant mice. Ethanol increased nuclear factor (NF)-κB binding activity in hepatocyte RXRα-deficient mice, but not in wild-type mice. In agreement, hepatic mRNA levels of proinflammatory cytokines and chemokines were increased to a greater extent in the mutant than in wild-type mice. Furthermore, signal transducer and activator of transcription factor (STAT) 3 and associated Bcl-xL induction was observed in ethanol-fed wild-type mice but not in ethanol-fed hepatocyte RXRα-deficient mice. Taken together, after ethanol treatment, hepatocyte RXRα deficiency results in lack of L-FABP induction, increased hepatic free fatty acids, NF-κB activation, and proinflammatory cytokines production and a lack of STAT3 activation, which in part may contribute to alcohol-induced liver damage. The American Society for Pharmacology and Experimental Therapeutics