Caspase regulation of genotoxin-induced neural precursor cell death.
Neural precursor cells (NPCs) critically regulate brain morphogenesis and recent studies have revealed an unexpectedly high frequency of NPC chromosomal abnormalities and apoptosis in the developing brain. We have shown previously that the apoptotic response of NPCs to genotoxic agents is dependent on p53 and caspase-9, but not Bax or caspase-3 expression. In this study, we found that NPCs deficient in Apaf-1, or both the pro-apoptotic multidomain Bcl-2 family members Bax and Bak, were resistant to cytosine arabinoside and gamma-irradiation-induced apoptosis. Inhibitors of gene transcription, protein translation, and caspase activity also blocked genotoxin-induced NPC apoptosis. Although caspase-3 and caspase-6 were both cleaved in response to DNA damage, neither of these effector caspases was critical for apoptosis. Genotoxin-induced NPC death was accompanied by the generation of reactive oxygen species and could be inhibited by several known antioxidants. Conversely, DNA damage-induced reactive oxygen species generation was inhibited significantly by gene disruption of p53, Apaf-1, or caspase-9, and combined deficiency of Bax and Bak, but not by caspase-3 or caspase-6 deficiency. These studies suggest that caspase-9 activation is both necessary and sufficient for genotoxin-induced neural precursor cell reactive oxygen species generation and death.
Division of Neuropathology, Department of Pathology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA.
Cleta
C
D'Sa
Barbara J
BJ
Klocke
Francesco
F
Cecconi
Tulia
T
Lindsten
Craig B
CB
Thompson
Stanley J
SJ
Korsmeyer
Richard A
RA
Flavell
Kevin A
KA
Roth
D000375:Aging; D000818:Animals; D053477:Apoptotic Protease-Activating Factor 1; D015153:Blotting, Western; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D002395:Catecholamines / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects* / Q000528:radiation effects; D002478:Cells, Cultured; D003561:Cytarabine / Q000494:pharmacology; D004249:DNA Damage; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004622:Embryo, Mammalian; D005260:Female; D048288:Imidazolines; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009153:Mutagens / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D011247:Pregnancy; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013687:Telencephalon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D014965:X-Rays; D050998:bcl-2 Homologous Antagonist-Killer Protein
C506593:Apaf1 protein, mouse; D053477:Apoptotic Protease-Activating Factor 1; C494773:Bak1 protein, mouse; D002395:Catecholamines; D018491:Dopamine Agonists; D048288:Imidazolines; D007166:Immunosuppressive Agents; D008565:Membrane Proteins; D009153:Mutagens; D011506:Proteins; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D050998:bcl-2 Homologous Antagonist-Killer Protein; D003561:Cytarabine; C011775:(3,4-dihydroxyphenylamino)-2-imidazoline; D020169:Caspases