Apoptosis induction in BEFV-infected Vero and MDBK cells through Src-dependent JNK activation regulates caspase-3 and mitochondria pathways.
Our previous report demonstrated that bovine ephemeral fever virus (BEFV)-infected cultured cells could induce caspase-dependent apoptosis. This study aims to further elucidate how BEFV activates the caspase cascade in bovine cells. BEFV replicated and induced apoptosis in Vero and Madin-Darby bovine kidney (MDBK) cells, and a kinetic study showed a higher efficiency of replication and a greater apoptosis induction ability of BEFV in Vero cells. Src and c-Jun N-terminal kinase (JNK) inhibitor, but not extracellular signal-regulated kinase (ERK) or p38 inhibitor, alleviated BEFV-mediated cytopathic effect and apoptosis. In BEFV-infected Vero and MDBK cells, BEFV directly induced Src tyrosine-418 phosphorylation and JNK phosphorylation and kinase activity, which was inhibited specifically by SU6656 and SP600125, respectively. The caspase cascade and its downstream effectors, Poly (ADP-ribose) polymerase (PARP) and DFF45, were also activated simultaneously upon BEFV infection. In addition, cytochrome c, but not Smac/DIABLO, was released gradually from mitochondria after BEFV infection. SU6656 suppressed Src, JNK, and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage; SP600125 reduced JNK and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage. Taken together, these results strongly support the hypothesis that a Src-dependent JNK signaling pathway plays a key role in BEFV-induced apoptosis. The molecular mechanism identified in our study may provide useful information for the treatment of BEFV.
Chen
Chun-Yen
CY
Graduate Institute and Department of Life Science, Tzu-Chi University, Hualien, Taiwan, Republic of China.
Chang
Chin-Yang
CY
Liu
Hung-Jen
HJ
Liao
Ming-Huei
MH
Chang
Chi-I
CI
Hsu
Jue-Liang
JL
Shih
Wen-Ling
WL
D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D045304:Cytochromes c / Q000378:metabolism; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018115:Ephemeral Fever Virus, Bovine / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D007211:Indoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D007668:Kidney / Q000166:cytology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D013449:Sulfonamides / Q000494:pharmacology; D014709:Vero Cells; D014779:Virus Replication; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
D000873:Anthracenes; D004791:Enzyme Inhibitors; D007211:Indoles; C416927:SU 6656; D013449:Sulfonamides; C432165:pyrazolanthrone; D045304:Cytochromes c; D019061:src-Family Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D053148:Caspase 3