CREB-mediated Bcl-2 protein expression after ischemic preconditioning.
Bcl-2 plays a pivotal role in the control of cell death and is upregulated by ischemic tolerance. Because Bcl-2 expression is regulated by the transcription factor cyclic AMP response element-binding protein (CREB), we investigated the role of CREB activation in two models of ischemic preconditioning: focal ischemic tolerance after middle cerebral artery occlusion (MCAO) and in vitro ischemic tolerance modeled by oxygen-glucose deprivation (OGD). After preconditioning ischemia (30 minutes MCAO or 30 minutes OGD), phosphorylation of CREB was increased, and there was an increased interaction between the bcl-2 cyclic AMP-responsive element (CRE) promoter and nuclear proteins after preconditioning ischemia in vivo and in vitro. Chromatin immunoprecipitation revealed an increased interaction between CREB-binding protein and the bcl-2 CRE rather than CREB, after preconditioning ischemia. Ischemic tolerance was blocked by a CRE decoy oligonucleotide, which also blocked Bcl-2 expression. The protein kinase A inhibitor H89, the calcium/calmodulin kinase inhibitor KN62, and the MEK inhibitor U0126 blocked ischemic tolerance, but not the phosphatidylinositol 3-kinase inhibitor LY294002. H89, KN62, and U0126 reduced CREB activation and Bcl-2 expression. Taken together, these data suggest that after ischemic preconditioning CREB activation regulates the expression of the prosurvival protein Bcl-2.
Meller
Robert
R
RS Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232, USA. rmeller@downeurobiology.org
Minami
Manabu
M
Cameron
Jennifer A
JA
Impey
Soren
S
Chen
Dexi
D
Lan
Jing-Quan
JQ
Henshall
David C
DC
Simon
Roger P
RP
D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology*; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D047908:Intracellular Signaling Peptides and Proteins / Q000187:drug effects / Q000378:metabolism; D019194:Ischemic Preconditioning; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D011494:Protein Kinases / Q000187:drug effects / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats
D017362:Cyclic AMP Response Element-Binding Protein; D047908:Intracellular Signaling Peptides and Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C015482:protein kinase modulator; D011494:Protein Kinases