The 3C protease activity of enterovirus 71 induces human neural cell apoptosis.
The human glioblastoma SF268 cell line was used to investigate the induction of apoptosis by the 3C protease of enterovirus 71 (EV71). Transient expression in these cells of the wild-type 3C protein encoded by EV71 induced morphological alterations typical of apoptosis, including generation of apoptotic bodies. Degradation of cellular DNA in nucleosomes was also observed. When two of the amino acids in the catalytic motif of 3C were changed by mutagenesis, the 3C protein not only lost its proteolytic activity, but also its ability to induce apoptosis in the SF268 cells. Twenty-four hours after 3C transfection, poly(ADP-ribose) polymerase, a DNA repair enzyme, was cleaved, indicating that caspases were activated by the expression of EV71 3C. The 3C-induced apoptosis was blocked by the caspase inhibitors DEVD-fmk and VAD-fmk. Our findings suggest that the proteolytic activity of 3C triggers apoptosis in the SF268 cells through a mechanism involving caspase activation and that this apoptotic pathway may play an important role in the pathogenesis of EV71 infection.
Li
Mei-Ling
ML
School of Medical Technology, Chang Gung University, Tao-Yuan, Taiwan.
Hsu
Tsu-An
TA
Chen
Tzu-Chun
TC
Chang
Shih-Cheng
SC
Lee
Jin-Ching
JC
Chen
Chiann-Chyi
CC
Stollar
Victor
V
Shih
Shin-Ru
SR
D000086042:3C Viral Proteases; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D061945:Caspase Inhibitors; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004770:Enterovirus / Q000201:enzymology* / Q000472:pathogenicity; D005909:Glioblastoma; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009707:Nucleosomes / Q000473:pathology; D009842:Oligopeptides / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D009707:Nucleosomes; D009842:Oligopeptides; D014764:Viral Proteins; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D004247:DNA; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases