Mice lacking TNF?a receptors 1 and 2 are resistant to death and fulminant liver injury induced by agonistic anti-Fas antibody

COSTELLI P; AOKI MP; CARBÓ N; REFFO P; LOPEZ SORIANO FJ; BONELLI G; ARGUILÉS JM; BACCINO FM

CELL DEATH AND DIFFERENTIATION

NATURE PUBLISHING GROUP

Año: 2003 vol. 10 p. 997 - 1004

1350-9047

The liver is particularly susceptible to Fas-mediated cytotoxicity. Mice given an adequate parenteral dose of agonistic anti- Fas antibody (aFas) or of FasL are known to develop a devastating liver injury and to die in a few hours. The present work shows that mice lacking TNFR1 and TNFR2 (R[1]) both survive a single dose of aFas, otherwise rapidly lethal, and develop a mild form of hepatic damage, compared to the much more severe liver injury that in a few hours strikes wildtype mice (Rþ), eventually involving increased activity of proteases of different families (caspase 3-, 8-, and 9-like, calpains, cathepsin B). Neither the overall tissue levels of Fas and FasL nor Fas expression at the hepatocyte surface are altered in the liver of R[1] animals. The DNA-binding activity of the NF-KB transcription factor is enhanced after aFas treatment, but much more markedly in R[1] than in Rþ mice. Bcl2, while unchanged in untreated animals, is markedly upregulated in R[1] but not in Rþ mice challenged with aFas. The requirement of a normal TNFR1/TNFR2 phenotype for full deployment of the general and liver-specific aFas toxicity in mice most likely implies that treatment with aFas in some way results in activation of the TNFa-TNFRs system and that this activation synergizes with Fas-mediated signals in causing the fulminant liver injury and the animal death. The precise cellular and molecular details underlying this interplay between Fas- and TNFRs-mediated signaling systems in the general and liver-specific aFas toxicity largely remain to be clarified.