The immunosuppressant drug FK506 prevents Fas-induced apoptosis in human hepatocytes.
FK506 is a potent immunosuppressive drug used for the prevention of graft rejection in organ transplantation. Experimental and clinical studies have shown correlations between apoptosis and graft rejection, and apoptosis also plays a role in cell death after ischemia-reperfusion injury in the rat liver. Fas-mediated apoptosis is very likely involved in allograft rejection and experimental evidence has shown a decrease of FasR expression in mouse hepatocytes produced by the drugs. On the basis of these findings we have investigated the protective effect of FK506 in comparison with cyclosporine A (CsA) on Fas-induced apoptosis, by analysing the activation of downstream effector caspases in human hepatocytes. Apoptosis was induced by treatment with agonistic antibodies against FasR, which resulted in a significant activation of caspase-3 after 12 h. Prevention of the downstream activation of the caspase cascade and apoptosis was observed when hepatocytes were pre-treated for 3 h with immunosuppressant drugs. A significant reduction (ca. 30-40%) of caspase-3 activation by 5 microM FK506 and CsA was observed. Along with less activation of caspase-3 a decrease of apoptotic DNA fragmentation was found. In addition, FK506 significantly reduced not only caspase-8 but also caspase-9 activation, to a similar extent as CsA, thus suggesting a protective effect at the mitochondrial level of this drug, as has already been reported for CsA. These effects of FK506 help to explain its strong anti-rejection properties and suggest promising benefits of pharmacological preconditioning on ischemia-reperfusion injury following liver transplantation.
Gómez-Lechón
M J
MJ
Centro de Investigación, Unidad de Hepatología Experimental, Hospital Universitario La Fe, Avda Campanar 21, E-47009 Valencia, Spain. gomez_mjo@gva.es
Serralta
A
A
Donato
M T
MT
Jiménez
N
N
O'connor
E
E
Castell
J V
JV
Mir
J
J
D000328:Adult; D000368:Aged; D017209:Apoptosis; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D016559:Tacrolimus / Q000494:pharmacology*; D019014:fas Receptor / Q000494:pharmacology*
D007166:Immunosuppressive Agents; D019014:fas Receptor; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; C505526:Casp8 protein, mouse; C505528:Casp8 protein, rat; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; D016559:Tacrolimus