title: Extended therapeutic window for caspase inhibition and synergy with MK-801 in the treatment of cerebral histotoxic hypoxia.
abstract: In rats, striatal histotoxic hypoxic lesions produced by the mitochondrial toxin malonate resemble those of focal cerebral ischemia. Intrastriatal injections of malonate induced cleavage of caspase-2 beginning at 6 h, and caspase-3-like activity as identified by DEVD biotin affinity-labeling within 12 h. DEVD affinity-labeling was prevented and lesion volume reduced in transgenic mice overexpressing BCL-2 in neuronal cells. Intrastriatal injection of the tripeptide, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), a caspase inhibitor, at 3 h, 6 h, or 9 h after malonate injections reduced the lesion volume produced by malonate. A combination of pretreatment with the NMDA antagonist, dizocilpine (MK-801), and delayed treatment with zVAD-fmk provided synergistic protection compared with either treatment alone and extended the therapeutic window for caspase inhibition to 12 h. Treatment with cycloheximide and zVAD-fmk, but not with MK-801, blocked the malonate-induced cleavage of caspase-2. NMDA injections alone resulted in a weak caspase-2 cleavage. These results suggest that malonate toxicity induces neuronal death by more than one pathway. They strongly implicate early excitotoxicity and delayed caspase activation in neuronal loss after focal ischemic lesions and offer a new strategy for the treatment of stroke.
authors: Experimental Neuropharmacology Laboratory, Department of Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, D-72076 Tübingen, Germany.jeorg.b.schulz@uni-tuebingen.de
authors: J B
authors: JB
authors: Schulz
authors: M
authors: M
authors: Weller
authors: R T
authors: RT
authors: Matthews
authors: M T
authors: MT
authors: Heneka
authors: P
authors: P
authors: Groscurth
authors: J C
authors: JC
authors: Martinou
authors: J
authors: J
authors: Lommatzsch
authors: R
authors: R
authors: von Coelln
authors: U
authors: U
authors: Wüllner
authors: P A
authors: PA
authors: Löschmann
authors: M F
authors: MF
authors: Beal
authors: J
authors: J
authors: Dichgans
authors: T
authors: T
authors: Klockgether
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000187:drug effects / Q000473:pathology*; D053143:Caspase 2; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D003513:Cycloheximide / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D016291:Dizocilpine Maleate / Q000494:pharmacology* / Q000627:therapeutic use; D004357:Drug Synergism; D019254:Genes, bcl-2; D006801:Humans; D002534:Hypoxia, Brain / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D020287:In Situ Nick-End Labeling; D008297:Male; D008314:Malonates / Q000633:toxicity; D051379:Mice; D008822:Mice, Transgenic; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D008314:Malonates; D018696:Neuroprotective Agents; D019253:Proto-Oncogene Proteins c-bcl-2; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D016291:Dizocilpine Maleate; D003513:Cycloheximide; C030290:malonic acid; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053143:Caspase 2; D053148:Caspase 3; D020169:Caspases