title: Cell culture model for acetaminophen-induced hepatocyte death in vivo.
abstract: Overdose of the popular, and relatively safe, analgesic acetaminophen (N-acetyl-p-aminophenol, APAP, paracetamol) can produce a fatal centrilobular liver injury. APAP-induced cell death was investigated in a differentiated, transforming growth factor alpha (TGFalpha)-overexpressing, hepatocyte cell line and found to occur at concentrations, and over time frames, relevant to clinical overdose situations. Coordinated multiorganellar collapse was evident during APAP-induced cytotoxicity with widespread, yet selective, protein degradation events in vitro. Cellular proteasomal activity was inhibited with APAP treatment but not with the comparatively nonhepatotoxic APAP regioisomer, N-acetyl-m-aminophenol (AMAP). Low concentrations of the proteasome-directed inhibitor MG132 (N-carbobenzoxyl-Leu-Leu-Leucinal) increased chromatin condensation and cellular stress responses preferentially in AMAP-treated cultures, suggesting a contribution of the proteasome in APAP- but not AMAP-mediated cell death. APAP-specific alterations to mitochondria were observed morphologically with evidence of mitochondrial proliferation in vitro. Biochemical alterations to cellular proteolytic events were also found in vivo, including APAP- or AMAP-mediated inhibition of caspase-3 processing. These results indicate that, although retaining some attributes of apoptosis, both APAP- and AMAP-mediated cell death have additional distinctive features consistent with longer term necrosis.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Pierce
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Franklin
authors.forename: Jean S
authors.initials: JS
authors.lastname: Campbell
authors.forename: Robert P
authors.initials: RP
authors.lastname: Tonge
authors.forename: Weichao
authors.initials: W
authors.lastname: Chen
authors.forename: Nelson
authors.initials: N
authors.lastname: Fausto
authors.forename: Sidney D
authors.initials: SD
authors.lastname: Nelson
authors.forename: Sam A
authors.initials: SA
authors.lastname: Bruschi
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology*; D000083:Acetanilides / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000083:Acetanilides; D000082:Acetaminophen; C026137:3-hydroxyacetanilide; D010447:Peptide Hydrolases; D020169:Caspases