Oxidative stress-mediated down-regulation of bcl-2 promoter in hippocampal neurons.
Generation of oxidative stress/reactive oxygen species (ROS) is one of the causes of neuronal apoptosis. We have examined the effects of ROS at the transcriptional level in an immortalized hippocampal neuronal cell line (H19-7) and in rat primary hippocampal neurons. Treatment of H19-7 cells with hydrogen peroxide (150 micro m) resulted in a 40% decrease in Bcl-2 protein and a parallel decrease in bcl-2 mRNA levels. H19-7 cells overexpressing bcl-2 were found to be resistant to ROS-induced apoptosis. We had previously shown that bcl-2 promoter activity is positively regulated by the transcription factor cyclic AMP response element binding protein (CREB) in neurons. In the present study, we demonstrate that ROS decreases the activity of luciferase reporter gene driven by a cyclic AMP response element site containing bcl-2 promoter. Exposure of neurons to ROS for 6 h resulted in basal and fibroblast growth factor-2-stimulated phosphorylation/activation of CREB. Chronic 24 h treatment with ROS led to a significant (p < 0.01) decrease in CREB protein and CREB mRNA levels. Adenoviral overexpression of wild type CREB in H19-7 cells resulted in significant (p < 0.01) protection against ROS-induced apoptosis through up-regulation of Bcl-2 expression whereas dominant negative CREB exaggerated the injury. These findings demonstrate that loss of CREB function contributes to oxidative stress-induced neuronal dysfunction.
Pugazhenthi
Subbiah
S
The Department of Medicine, University of Colorado Health Sciences Center, Denver, CO 80220, USA.
Nesterova
Albina
A
Jambal
Purevsuren
P
Audesirk
Gerald
G
Kern
Marcey
M
Cabell
Leigh
L
Eves
Eva
E
Rosner
Marsha R
MR
Boxer
Linda M
LM
Reusch
Jane E-B
JE
D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology; D005949:Glucose Oxidase; D006624:Hippocampus / Q000166:cytology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D017362:Cyclic AMP Response Element-Binding Protein; D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D005949:Glucose Oxidase