Potential dengue virus-triggered apoptotic pathway in human neuroblastoma cells: arachidonic acid, superoxide anion, and NF-kappaB are sequentially involved.
Direct in vivo evidence for the susceptibility of human neuronal cells to dengue virus has not been reported. In this study, we demonstrated that type 2 dengue (DEN-2) virus infection induced extensive apoptosis in the human neuroblastoma cell line SK-N-SH. Phospholipase A(2) (PLA(2)) was activated by DEN-2 infection, which led to the generation of arachidonic acid (AA). Inhibition of PLA(2) activity by the PLA(2) inhibitors, AACOCF(3) and ONO-RS-082, diminished DEN-2 virus-induced apoptosis. In contrast, the cyclooxygenase inhibitors aspirin and indomethacin, thought to increase AA accumulation by blocking AA catabolism, enhanced apoptosis. Exogenous AA induced apoptosis in a dose-dependent manner. Superoxide anion, which is thought to be generated through the AA-activated NADPH oxidase, was increased after infection. Pretreatment with superoxide dismutase (SOD) protected cells against DEN-2 virus-induced apoptosis. Furthermore, generation of superoxide anion was blocked by AACOCF(3). In addition, the transcription factors, NF-kappaB and c-Jun, were found to be activated after DEN-2 virus infection. However, pretreatment of cells with oligodeoxynucleotides containing NF-kappaB, but not c-Jun, binding sites (transcription factor decoy) strongly prevented dengue virus-induced apoptosis. The finding that AACOCF(3) and SOD significantly block activation of NF-kappaB suggests that this activation is derived from the AA-superoxide anion pathway. Our results indicate that DEN-2 virus infection of human neuroblastoma cells triggers an apoptotic pathway through PLA(2) activation to superoxide anion generation and subsequently to NF-kappaB activation. This apoptotic effect can be either directly derived from the action of AA and superoxide anion on mitochondria or indirectly derived from the products of apoptosis-related genes activated by NF-kappaB.
Jan
J T
JT
Institute of Preventive Medicine, National Defense Medical Center, Taipei, Republic of China.
Chen
B H
BH
Ma
S H
SH
Liu
C I
CI
Tsai
H P
HP
Wu
H C
HC
Jiang
S Y
SY
Yang
K D
KD
Shaio
M F
MF
D000818:Animals; D017209:Apoptosis; D016718:Arachidonic Acid / Q000378:metabolism* / Q000494:pharmacology; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D006224:Cricetinae; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D003716:Dengue Virus / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020287:In Situ Nick-End Labeling; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000201:enzymology; D016328:NF-kappa B / Q000378:metabolism*; D009447:Neuroblastoma; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D016328:NF-kappa B; D016755:Proto-Oncogene Proteins c-jun; D013481:Superoxides; D016718:Arachidonic Acid; D013482:Superoxide Dismutase; D010741:Phospholipases A; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases