Differential expression profiles of PLC-beta1 and -delta1 in primary cultured rat cortical neurons treated with N-methyl-D-aspartate and peroxynitrite.
Phospholipase C (PLC)-delta1 protein appears to accumulate aberrantly in Alzheimer's disease brains and its expression is reported to be induced by overstimulation of N-methyl-D-aspartate (NMDA) receptor, but there is little knowledge on its physiological role. To clarify this, we examined the expression profile of PLC-delta1 in primary cultured rat cortical neurons treated with NMDA or peroxynitrite, in comparison with those of PLC-beta1 and -gamma1, the overexpression of both of which protects cells from oxidative stress. Overstimulation of NMDA receptor decreased and increased the expression of PLC-beta1 and -delta1, respectively, but did not affect that of PLC-gamma1, in the neurons. The viability of neurons decreased depending on the period of treatment with S-nitroso-N-acetyl D,L-penicillamine (SNAP), there being a significant decrease on 9 h treatment. On examination of the expression profiles of PLC isozymes after treatment of neurons with SNAP, PLC-beta1 was found to be increased after 1h treatment and decreased after 9 h treatment, while PLC-delta1 was significantly increased, especially after 5 h treatment. Peroxynitrite treatment caused a dose-dependent decrease in the viability of neurons, and expression of PLC-beta1 was increased by a nontoxic level of peroxynitrite and decreased by a toxic level of it, while that of PLC-delta1 was increased by a sublethal level of it. These findings suggested that induction of PLC-beta1 might protect neurons from oxidative stress, but that of PLC-delta1 might have the opposite role, although both isozymes responded to oxidative stress.
Department of Environmental Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan. nagasawa@mb.kyoto-phu.ac.jp
Kazuki
K
Nagasawa
Kentaro
K
Nishida
Katsuhito
K
Nagai
Shun
S
Shimohama
Sadaki
S
Fujimoto
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004347:Drug Interactions; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007527:Isoenzymes / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D051381:Rats; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors; D010738:Type C Phospholipases / Q000145:classification / Q000378:metabolism*
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D007527:Isoenzymes; C110881:S-nitro-N-acetylpenicillamine; D013778:Tetrazolium Salts; D013844:Thiazoles; D030421:Peroxynitrous Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D010738:Type C Phospholipases; C022616:thiazolyl blue; D010396:Penicillamine