Calpains mediate p53 activation and neuronal death evoked by DNA damage.
DNA damage is an initiator of neuronal death implicated in neuropathological conditions such as stroke. Previous evidence has shown that apoptotic death of embryonic cortical neurons treated with the DNA damaging agent camptothecin is dependent upon the tumor suppressor p53, an upstream death mediator, and more distal death effectors such as caspases. We show here that the calcium-regulated cysteine proteases, calpains, are activated during DNA damage induced by camptothecin treatment. Moreover, calpain deficiency, calpastatin expression, or pharmacological calpain inhibitors prevent the death of embryonic cortical neurons, indicating the important role of calpain in DNA damage-induced death. Calpain inhibition also significantly reduced and delayed the induction of p53. Consistent with the actions of calpains upstream of p53 and the proximal nature of p53 death signaling, calpain inhibition inhibited cytochrome c release and DEVD-AFC cleavage activity. Taken together, our results indicate that calpains are a key mediator of p53 induction and consequent caspase-dependent neuronal death due to DNA damage.
Ottawa Health Research Institute, Neuroscience Group, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
Mary
M
Sedarous
Elizabeth
E
Keramaris
Michael
M
O'Hare
Edon
E
Melloni
Ruth S
RS
Slack
John S
JS
Elce
Peter A
PA
Greer
David S
DS
Park
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002166:Camptothecin / Q000378:metabolism / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002470:Cell Survival; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004249:DNA Damage; D049452:Green Fluorescent Proteins; D006579:Heterozygote; D007150:Immunohistochemistry; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D003574:Cytochrome c Group; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D049452:Green Fluorescent Proteins; C033668:calpastatin; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D002154:Calpain; D020169:Caspases; D003546:Cysteine Endopeptidases; D002166:Camptothecin