A Bcl-2 antisense oligonucleotide increases alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) toxicity in cortical cultures.
Both alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated neurotoxicity and the induction of death-regulatory genes have been implicated in the pathophysiology of delayed ischemic neuronal injury. To assess the role of the antiapoptotic gene Bcl-2 in the modulation of AMPA toxicity, we exposed neuron-enriched cultures from rat cerebral cortex to AMPA, in the absence or presence of an antisense oligodeoxynucleotide (ODN) directed against Bcl-2. AMPA produced concentration-dependent toxicity detected by a decrease in fluorescence of the redox indicator Alamar blue and by an increase in lactic acid dehydrogenase release. This effect was accompanied by the induction of Bcl-2 protein expression, with maximal induction at 100 microM AMPA. A phosphorothioate antisense ODN against Bcl-2 reduced the AMPA-stimulated induction of Bcl-2 protein levels, detected by western blotting, by about 70%. In the presence of the antisense ODN, but not sense or scrambled ODNs, the toxicity of 100 microM AMPA was increased by about 60%. These findings suggest that induction of Bcl-2 expression by AMPA may have a protective role to limit AMPA receptor-mediated neuronal damage and that modifying Bcl-2 expression could have therapeutic potential in ischemia.
White
M J
MJ
Department of Neurology, University of Pittsburgh School of Medicine, PA 15261, USA.
Chen
J
J
Zhu
L
L
Irvin
S
S
Sinor
A
A
DiCaprio
M J
MJ
Jin
K
K
Greenberg
D A
DA
D000818:Animals; D016375:Antisense Elements (Genetics) / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D015870:Gene Expression / Q000187:drug effects; D009474:Neurons / Q000502:physiology*; D015345:Oligonucleotide Probes / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000633:toxicity*
D016375:Antisense Elements (Genetics); D018690:Excitatory Amino Acid Agonists; D015345:Oligonucleotide Probes; D019253:Proto-Oncogene Proteins c-bcl-2; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid