Growth factors prevent changes in Bcl-2 and Bax expression and neuronal apoptosis induced by nitric oxide.
Recent studies have shown that nitric oxide (NO) donors can trigger apoptosis of neurons, and growth factors such as insulin-like growth factor-1 (IGF-1) and basic fibroblast growth factor (bFGF) can protect against NO-induced neuronal cell death. The purpose of this study was to elucidate the possible mechanisms of NO-mediated neuronal apoptosis and the neuroprotective action of these growth factors. Both IGF-1 and bFGF prevented apoptosis induced by NO donors, sodium nitroprusside (SNP) or 3-morpholinosydnonimin (SIN-1) in hippocampal neuronal cultures. Incubation of neurons with SNP induced caspase-3-like activation following downregulation of Bcl-2 and upregulation of Bax protein levels in cultured neurons. Treatment of neurons with a bax antisense oligonucleotide inhibited the caspase-3-like activation and neuronal death induced by SNP. In addition, treatment of neurons with an inhibitor of caspase-3, Ac-DEVD-CHO, together with SNP did not affect the changes in the protein levels, although it inhibited NO-induced cell death. Pretreatment of cultures with either IGF-1 or bFGF prior to NO exposure inhibited caspase-3-like activation together with the changes in Bcl-2 and Bax protein levels. These results suggest that the changes in Bcl-2 and Bax protein levels followed by caspase-3-like activation are a component in the cascade of NO-induced neuronal apoptosis, and that the neuroprotective actions of IGF-1 and bFGF might be due to inhibition of the changes in the protein levels of the Bcl-2 family.
Tamatani
M
M
Department of Anatomy and Neuroscience, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan. tama@anat2.med.osaka-u.ac.jp
Ogawa
S
S
Nuñez
G
G
Tohyama
M
M
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053938:DNA Fragmentation; D004622:Embryo, Mammalian; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006133:Growth Substances / Q000494:pharmacology* / Q000502:physiology; D006624:Hippocampus / Q000166:cytology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic; D051028:bcl-2-Associated X Protein
C494828:Bax protein, rat; D015853:Cysteine Proteinase Inhibitors; D006133:Growth Substances; D020030:Nitric Oxide Donors; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D051028:bcl-2-Associated X Protein; D016222:Fibroblast Growth Factor 2; D009599:Nitroprusside; D009569:Nitric Oxide; C002385:linsidomine; D007334:Insulin-Like Growth Factor I; D008981:Molsidomine; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases