Toxic bile salts induce rodent hepatocyte apoptosis via direct activation of Fas
Open Access
- 1 January 1999
- journal article
- Published by American Society for Clinical Investigation in JCI Insight
- Vol. 103 (1), 137-145
- https://doi.org/10.1172/jci4765
Abstract
Cholestatic liver injury appears to result from the induction of hepatocyte apoptosis by toxic bile salts such as glycochenodeoxycholate (GCDC). Previous studies from this laboratory indicate that cathepsin B is a downstream effector protease during the hepatocyte apoptotic process. Because caspases can initiate apoptosis, the present studies were undertaken to determine the role of caspases in cathepsin B activation. Immunoblotting of GCDC-treated McNtcp.24 hepatoma cells demonstrated cleavage of poly(ADP-ribose) polymerase and lamin B1 to fragments that indicate activation of effector caspases. Transfection with CrmA, an inhibitor of caspase 8, prevented GCDC-induced cathepsin B activation and apoptosis. Consistent with these results, an increase in caspase 8–like activity was observed in GCDC-treated cells. Examination of the mechanism of GCDC-induced caspase 8 activation revealed that dominant-negative FADD inhibited apoptosis and that hepatocytes isolated from Fas-deficient lymphoproliferative mice were resistant to GCDC-induced apoptosis. After GCDC treatment, immunoprecipitation experiments demonstrated Fas oligomerization, and confocal microscopy demonstrated ΔFADD-GFP (Fas-associated death domain–green fluorescent protein, aggregation in the absence of detectable Fas ligand mRNA. Collectively, these data suggest that GCDC-induced hepatocyte apoptosis involves ligand-independent oligomerization of Fas, recruitment of FADD, activation of caspase 8, and subsequent activation of effector proteases, including downstream caspases and cathepsin B.Keywords
This publication has 44 references indexed in Scilit:
- ERICE, a Novel FLICE-activatable CaspasePublished by Elsevier BV ,1998
- Bcl-xL Functions Downstream of Caspase-8 to Inhibit Fas- and Tumor Necrosis Factor Receptor 1-induced Apoptosis of MCF7 Breast Carcinoma CellsPublished by Elsevier BV ,1998
- Role of an acidic compartment in tumor‐necrosis‐factor‐α−induced production of ceramide, activation of caspase‐3 and apoptosisEuropean Journal of Biochemistry, 1998
- Apoptosis by Death FactorCell, 1997
- Selective induction of apoptosis in Hep 3B cells by topoisomerase I inhibitors: evidence for a protease-dependent pathway that does not activate cysteine protease P32.JCI Insight, 1996
- FLICE, A Novel FADD-Homologous ICE/CED-3–like Protease, Is Recruited to the CD95 (Fas/APO-1) Death-Inducing Signaling ComplexCell, 1996
- Involvement of MACH, a Novel MORT1/FADD-Interacting Protease, in Fas/APO-1- and TNF Receptor–Induced Cell DeathCell, 1996
- A License to KillCell, 1996
- Lethal effect of the anti-Fas antibody in miceNature, 1993
- The slow-binding and slow, tight-binding inhibition of enzyme-catalysed reactionsTrends in Biochemical Sciences, 1982