Bid cleavage, cytochrome c release and caspase activation in canine coronavirus-induced apoptosis.
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 (PARPs) 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 c 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.
De Martino
Luisa
L
Department of Pathology and Animal Health, Infectious Diseases, Faculty of Veterinary Medicine, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy.
Marfé
Gabriella
G
Longo
Mariangela
M
Fiorito
Filomena
F
Montagnaro
Serena
S
Iovane
Valentina
V
Decaro
Nicola
N
Pagnini
Ugo
U
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053178:Caspase 6 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D017939:Coronavirus, Canine / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism*; D004285:Dogs; D005434:Flow Cytometry
D015853:Cysteine Proteinase Inhibitors; D045304:Cytochromes c; D053148:Caspase 3; D053178:Caspase 6; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases