Bid cleavage, cytochrome release and caspase activation in canine coronavirus-induced apoptosis

Luisa de Martino , Gabriella Marfé , Mariangela Longo , Filomena Fiorito , Serena Montagnaro , Valentina Iovane , Nicola Decaro , Ugo Pagnini

A previous study demonstrated that infection of a canine fibrosarcoma cell line (A-72 cells) by canine coronavirus (CCoV) resulted in apoptosis (Ruggieri et al., 2007). In this study, we investigated the cell death processes during infection and the underlying mechanisms. We found that CCoV-II triggers apoptosis in A-72 cells by activating initiator (caspase-8 and -9) and executioner (caspase-3 and -6) caspases. The proteolytic cleavage of poly(ADP-ribose) polymerases (PARP) confirmed the activation of executioner caspases. Furthermore, CCoV-II infection resulted in truncated bid (tbid) translocation from the cytosolic to the mitochondrial fraction, the cytochrome release from mitochondria, and alterations in the pro- and anti-apoptotic proteins of bcl-2 family. Our data indicated that, in this experimental model, both intrinsic and extrinsic pathways are involved. In addition, we demonstrated that the inhibition of apoptosis by caspase inhibitors did not affect CCoV replication, suggesting that apoptosis does not play a role in facilitating viral release.

Mots clés: Canine coronavirus type II; apoptosis; caspases; PARP; bcl-2 family members

Luisa de Martino, Gabriella Marfé, Mariangela Longo, Filomena Fiorito, Serena Montagnaro, et al.. Bid cleavage, cytochrome release and caspase activation in canine coronavirus-induced apoptosis. Veterinary Microbiology, 2010, 141 (1-2), pp.36. ⟨10.1016/j.vetmic.2009.09.001⟩. ⟨hal-00560853⟩