Apoptosis induced by inhibition of cyclic AMP response element-binding protein in vascular smooth muscle cells.
BACKGROUND
The balance between apoptosis and proliferation of vascular smooth muscle cells (VSMCs) is believed to contribute to the vascular remodeling process. Cyclic AMP response element-binding protein (CREB) is a critical transcription factor for the survival of neuronal cells and T lymphocytes. However, the role of CREB in blood vessels is incompletely characterized.


RESULTS
Nuclear staining with Hoechst 33258 or propidium iodine showed an increase in apoptotic cells with activation of caspase-3 in VSMCs infected with adenovirus expressing the dominant-negative form of CREB (AdCREBM1). Basal expression of Bcl-2 and Bcl-2 promoter activity were decreased by infection with AdCREBM1. Immunohistochemistry revealed that CREB was mainly induced and activated in the neointimal alpha-smooth muscle actin-positive cells of rat carotid artery after balloon injury. Infection with AdCREBM1 suppressed neointimal formation (intima-media ratio) by 33.8% after 14 days of injury, which was accompanied by an increase in apoptosis as indicated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells and a decrease in bromodeoxyuridine incorporation.


CONCLUSIONS
These results suggest that CRE-dependent gene transcription might play an important role in the survival and proliferation of VSMCs. CREB might be a novel transcription factor mediating the vascular remodeling process and a potential therapeutic target for atherosclerotic disease.
Tokunou
Tomotake
T
Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, 812-8582 Fukuoka, Japan.
Shibata
Rei
R
Kai
Hisashi
H
Ichiki
Toshihiro
T
Morisaki
Takashi
T
Fukuyama
Kae
K
Ono
Hiroki
H
Iino
Naoko
N
Masuda
Satoko
S
Shimokawa
Hiroaki
H
Egashira
Kensuke
K
Imaizumi
Tsutomu
T
Takeshita
Akira
A
D000800:Angioplasty, Balloon; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001973:Bromodeoxyuridine / Q000493:pharmacokinetics; D017536:Carotid Artery, Common / Q000187:drug effects / Q000378:metabolism; D002455:Cell Division; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D015870:Gene Expression / Q000187:drug effects; D005799:Genes, Dominant; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D020287:In Situ Nick-End Labeling; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D014162:Transfection; D017539:Tunica Intima / Q000187:drug effects / Q000378:metabolism
D017362:Cyclic AMP Response Element-Binding Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D001973:Bromodeoxyuridine