ABSTRACT
Acetaminophen (N-acetyl-para-aminophenol (APAP), paracetamol) is a commonly used analgesic and antipyretic agent. Although considered safe at therapeutic doses, accidental or intentional overdose causes acute liver failure characterized by centrilobular hepatic necrosis with high morbidity and mortality. Although many molecular aspects of APAP-induced cell death have been described, no conclusive mechanism has been proposed. We recently identified TNF-related apoptosis-inducing ligand (TRAIL) and c-Jun kinase (JNK)-dependent activation of the pro-apoptotic Bcl-2 homolog Bim as an important apoptosis amplification pathway in hepatocytes. In this study, we, thus, investigated the role of TRAIL, c-JNK and Bim in APAP-induced liver damage. Our results demonstrate that TRAIL strongly synergizes with APAP in inducing cell death in hepatocyte-like cells lines and primary hepatocyte. Furthermore, we found that APAP strongly induces the expression of Bim in a c-JNK-dependent manner. Consequently, TRAIL- or Bim-deficient mice were substantially protected from APAP-induced liver damage. This study identifies the TRAIL-JNK-Bim axis as a novel target in the treatment of APAP-induced liver damage and substantiates its general role in hepatocyte death.
Subject(s)
Acetaminophen/toxicity , Apoptosis Regulatory Proteins/metabolism , Chemical and Drug Induced Liver Injury/metabolism , Liver/drug effects , Liver/metabolism , Membrane Proteins/metabolism , Proto-Oncogene Proteins/metabolism , TNF-Related Apoptosis-Inducing Ligand/metabolism , Animals , Apoptosis Regulatory Proteins/deficiency , Bcl-2-Like Protein 11 , Cell Death/drug effects , Chemical and Drug Induced Liver Injury/pathology , Hepatocytes/cytology , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Liver/cytology , Membrane Proteins/deficiency , Mice , Mice, Inbred C57BL , Mice, Knockout , Proto-Oncogene Proteins/deficiency , TNF-Related Apoptosis-Inducing Ligand/deficiency , Tumor Cells, CulturedABSTRACT
The Thiobacillus versutus asd gene coding for aspartate-semialdehyde dehydrogenase was cloned in Escherichia coli cells using pBR322 as a vector. The gene was expressed independently of its orientation, suggesting that E. coli RNA polymerase recognized T. versutus promoter sequence. The T. versutus DNA coded protein, of the molecular weight 44,000, was identified by the analysis of the proteins produced by minicells.
