Canine distemper virus induces apoptosis through caspase-3 and -8 activation in vero cells.
We investigated the signal-transduction pathway of canine distemper virus-Onderstepoort (CDV-Ond) vaccine strain-mediated apoptosis in Vero cells. Canine distemper virus-Onderstepoort at a multiplicity of infection (MOI) of 0.1 induced DNA fragmentation 48 h after infection. Immunofluorescence staining revealed that 57% +/- 4% of the CDV-N-protein-positive cells were terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive, and all TUNEL-positive cells were CDV-N-protein-positive, indicating that CDV-Ond induced apoptosis only in the infected cells. We also found that CDV-Ond infection induced activation of caspase-3 and caspase-8. In the semi-quantitative reverse transcription-polymerase chain reaction assay for apoptosis-related genes, the expression of mRNA of the death receptor, Fas, was also increased in CDV-Ond-infected cells. In contrast, the expressions of Bcl-2 and Bax, regulators for intrinsic apoptotic signaling through the mitochondria, did not change. These results suggest that CDV-Ond induced apoptosis by activating caspase-3, possibly through caspase-8 signaling rather than through p53/Bax-mediated, mitochondrial signaling in the infected cells.
Kajita
M
M
Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Katayama
H
H
Murata
T
T
Kai
C
C
Hori
M
M
Ozaki
H
H
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D002522:Chlorocebus aethiops; D053938:DNA Fragmentation; D004216:Distemper / Q000201:enzymology / Q000821:virology*; D004217:Distemper Virus, Canine / Q000472:pathogenicity*; D004283:Dog Diseases / Q000201:enzymology / Q000821:virology*; D004285:Dogs; D020287:In Situ Nick-End Labeling; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D015398:Signal Transduction; D014709:Vero Cells / Q000821:virology
D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases