Cytosolic phospholipase A alpha modulates NMDA neurotoxicity in mouse hippocampal cultures.
The arachidonic acid-specific cytosolic phospholipase A(2) alpha (cPLA(2)alpha) has been implicated in the generation of neurological injuries. cPLA(2)alpha-dependent neurological injury has been postulated to be mediated through inflammatory and eicosanoid pathways. We determined if cPLA(2)alpha amplifies the injury of a non-inflammatory, excitotoxic stimulus by modifying a well-described toxicity assay to measure the toxicity of N-methyl-d-aspartate (NMDA) in the CA1 region of organotypic, mouse hippocampal cultures. Hippocampal cultures from wild-type and cPLA(2)alpha knockout mice were exposed to 5, 7.5 or 10 microm NMDA for 1 h. Toxicity was measured 23 h later. Cultures derived from cPLA(2)alpha(-/-) mice and cultures treated with the selective inhibitor AACOCF(3) were significantly protected from NMDA toxicity, as compared with wild-type cultures. To determine if cPLA(2)alpha-dependent toxicity is cyclooxygenase (COX)-2 dependent, COX-2 and PGE(2) levels were measured 7 and 25 h after NMDA treatment. NMDA treatment failed to induce COX-2 protein or increase PGE(2) in the culture media in either genotype at either time. In contrast, phorbol 12-myristate 13-acetate and ionophore treatment caused robust induction of COX-2 and PGE(2) in both genotypes. We conclude that cPLA(2)alpha may have a hitherto unrecognized direct effect on excitatory neurotoxicity, suggesting that cPLA(2)alpha inhibition is a therapeutic candidate for treatment of the early, excitotoxic injury observed in stroke.
Brady
Ken M
KM
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Texel
Sarah J
SJ
Kishimoto
Koji
K
Koehler
Raymond C
RC
Sapirstein
Adam
A
D000818:Animals; D000831:Animals, Newborn; D001095:Arachidonic Acids / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016202:N-Methylaspartate / Q000633:toxicity*; D009578:Nitrobenzenes / Q000494:pharmacology; D009924:Organ Culture Techniques; D010741:Phospholipases A / Q000172:deficiency / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D001095:Arachidonic Acids; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D009578:Nitrobenzenes; D013449:Sulfonamides; C081565:arachidonyltrifluoromethane; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D016202:N-Methylaspartate; D051546:Cyclooxygenase 2; D010741:Phospholipases A; D013755:Tetradecanoylphorbol Acetate