RT Journal Article
SR Electronic
T1 The Aryl Hydrocarbon Receptor Predisposes Hepatocytes to Fas-Mediated Apoptosis
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 612
OP 622
DO 10.1124/mol.104.005223
VO 67
IS 3
A1 Kyung-Tae Park
A1 Kristen A. Mitchell
A1 Gengming Huang
A1 Cornelis J. Elferink
YR 2005
UL http://molpharm.aspetjournals.org/content/67/3/612.abstract
AB Liver homeostasis is achieved by the removal of diseased and damaged hepatocytes and their coordinated replacement to maintain a constant liver cell mass. Cirrhosis, viral hepatitis, and toxic drug effects can all trigger apoptosis in the liver as a means of removing the unwanted cells, and the Fas “death receptor” pathway comprises a major physiological mechanism by which this occurs. The susceptibility to Fas-mediated apoptosis is, in part, a function of the hepatocyte's proteome. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known to influence apoptosis, conceivably by regulating the expression of genes involved in apoptotic signaling. In this article, we present evidence demonstrating that AhR expression and function promote apoptosis in liver cells in response to Fas stimulation. Reintroduction of the AhR into the AhR-negative BP8 hepatoma cells as well as into primary hepatocytes from AhR knockout mice increases the magnitude of cell death in response to Fas ligand. Enhanced apoptosis correlates with increased caspase activity and mitochondrial cytochrome c release but not with the expression of several Bcl-2 family proteins. In vivo studies showed that in contrast to wild-type mice, AhR knockout mice are protected from the lethal effects of the anti-Fas Jo2 antibody. Moreover, down-regulation of the aryl hydrocarbon receptor nuclear translocator protein in vivo by adenovirus-mediated RNA interference to suppress AhR activity provided wild-type mice partial protection from Jo2-induced lethality.