Role of caspase-3 activation in cerebral ischemia-induced neurodegeneration in adult and neonatal brain.
These studies have addressed the role of caspase-3 activation in neuronal death after cerebral ischemia in different animal models. The authors were unable to show activation of procaspase-3 measured as an induction of DEVDase (Asp-Glu-Val-Asp) activity after focal or transient forebrain ischemia in rats. DEVDase activity could not be induced in the cytosolic fraction of the brain tissue obtained from these animals by exogenous cytochrome c/dATP and Ca2+. However, the addition of granzyme B to these cytosolic fractions resulted in a significant activation of DEVDase, confirming that the conditions were permissive to analyze proteolytic cleavage of the DEVD-AMC (7-amino-4-methyl-coumarin) substrate. Consistent with these findings, zVal-Ala-Asp-fluoromethylketone administered after focal ischemia did not have a neuroprotective effect. In contrast to these findings, a large increase in DEVDase activity was detected in a model of hypoxic-ischemia in postnatal-day-7 rats. Furthermore, in postnatal-day-7 animals treated with MK-801, in which it has been suggested that excessive apoptosis is induced, the authors were unable to detect activation of DEVDase activity but were able to induce it in vitro by the addition of cytochrome c/dATP and Ca2+ to the cytosolic fraction. Analysis of cytochrome c distribution did not provide definitive evidence for selective cytochrome c release in the permanent focal ischemia model, whereas in the transient model a small but consistent amount of cytochrome c was found in the cytosolic fraction. However, in both models the majority of cytochrome c remained associated with the mitochondrial fraction. In conclusion, the authors were unable to substantiate a role of mitochondrially derived cytochrome c and procaspase-3 activation in ischemia-induced cell death in adult brain, but did see a clear induction of caspase-3 in neonatal hypoxia.
Gill
Ramanjit
R
F. Hoffmann-La Roche Ltd., Preclinical Research Basel, CNS Department, Basel, Switzerland. J.R.Kemp@Datacomm.ch
Soriano
Marc
M
Blomgren
Klas
K
Hagberg
Henrik
H
Wybrecht
Remy
R
Miss
Marie-Therese
MT
Hoefer
Sandra
S
Adam
Geo
G
Niederhauser
Olivier
O
Kemp
John A
JA
Loetscher
Hansruedi
H
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology* / Q000254:growth & development / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death; D003574:Cytochrome c Group / Q000378:metabolism; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004789:Enzyme Activation; D053804:Granzymes; D006801:Humans; D020244:Infarction, Middle Cerebral Artery; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012697:Serine Endopeptidases / Q000494:pharmacology
D000590:Amino Acid Chloromethyl Ketones; D003574:Cytochrome c Group; D018696:Neuroprotective Agents; D011498:Protein Precursors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D016291:Dizocilpine Maleate; D010447:Peptide Hydrolases; C509213:GZMB protein, human; D053804:Granzymes; C509214:Gzmb protein, mouse; C509215:Gzmb protein, rat; D012697:Serine Endopeptidases; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C108711:DEVDase