Involvement of caspase 3 in apoptotic death of cortical neurons evoked by DNA damage.
Previous reports have shown that DNA-damage-evoked death of embryonic cortical neurons is delayed by general caspase inhibitors and is accompanied by an increase in DEVD-AFC cleavage activity. We show here that this cleavage activity is lacking in camptothecin-treated caspase 3-deficient neurons. Moreover, we report that death of camptothecin-treated caspase 3-deficient neurons cultured from E16 embryos is delayed and that no significant increase in survival is observed with cotreatment with the general caspase inhibitor BAF. These results indicate that caspase-dependent death of camptothecin-treated cortical neurons requires caspase 3 activity. The delay in death is accompanied by impairment of DNA fragmentation. However, Bax-dependent cytochrome c release still occurs in camptothecin-treated caspase 3-deficient cortical neurons. Accordingly, we hypothesize that the delayed death which occurs in the absence of caspase 3 activity may be due to mitochondrial dysfunction. Finally, we show that the delay in death observed with E16 caspase 3-deficient neurons does not occur in neurons cultured from E19 embryos. This suggests that the requirement for caspase 3 in death of neurons evoked by DNA damage may differ depending upon the developmental state of the cell.
Keramaris
E
E
Neuroscience Research Institute, University of Ottawa, Ontario, Canada.
Stefanis
L
L
MacLaurin
J
J
Harada
N
N
Takaku
K
K
Ishikawa
T
T
Taketo
M M
MM
Robertson
G S
GS
Nicholson
D W
DW
Slack
R S
RS
Park
D S
DS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D001921:Brain / Q000166:cytology / Q000196:embryology; D002166:Camptothecin / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000235:genetics* / Q000378:metabolism; D003374:Coumarins / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D004249:DNA Damage / Q000502:physiology*; D053938:DNA Fragmentation / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D020287:In Situ Nick-End Labeling; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology* / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology
D003374:Coumarins; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D009842:Oligopeptides; C115495:aspartyl-glutamyl-valyl-aspartyl-7-amino-4-trifluoromethylcoumarin; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D002166:Camptothecin