Molecular mechanism of fibronectin gene activation by cyclic stretch in vascular smooth muscle cells.
Fibronectin plays an important role in vascular remodeling. A functional interaction between mechanical stimuli and locally produced vasoactive agents is suggested to be crucial for vascular remodeling. We examined the effect of mechanical stretch on fibronectin gene expression in vascular smooth muscle cells and the role of vascular angiotensin II in the regulation of the fibronectin gene in response to stretch. Cyclic stretch induced an increase in vascular fibronectin mRNA levels that was inhibited by actinomycin D and CV11974, an angiotensin II type 1 receptor antagonist; cycloheximide and PD123319, an angiotensin II type 2 receptor antagonist, did not affect the induction. In transfection experiments, fibronectin promoter activity was stimulated by stretch and inhibited by CV11974 but not by PD123319. DNA-protein binding experiments revealed that cyclic stretch enhanced nuclear binding to the AP-1 site, which was partially supershifted by antibody to c-Jun. Site-directed mutation of the AP-1 site significantly decreased the cyclic stretch-mediated activation of fibronectin promoter. Furthermore, antisense c-jun oligonucleotides decreased the stretch-induced stimulation of the fibronectin promoter activity and the mRNA expression. These results suggest that cyclic stretch stimulates vascular fibronectin gene expression mainly via the activation of AP-1 through the angiotensin II type 1 receptor.
Cardiovascular Research, Department of Internal Medicine II, Yokohama City University School of Medicine, Yokohama 236, Japan. tamukou@med.yokohama-u.ac.jp
K
K
Tamura
Y E
YE
Chen
M
M
Lopez-Ilasaca
L
L
Daviet
N
N
Tamura
T
T
Ishigami
M
M
Akishita
I
I
Takasaki
Y
Y
Tokita
R E
RE
Pratt
M
M
Horiuchi
V J
VJ
Dzau
S
S
Umemura
D000804:Angiotensin II / Q000378:metabolism; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D003609:Dactinomycin / Q000494:pharmacology; D005353:Fibronectins / Q000235:genetics*; D005786:Gene Expression Regulation; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D011945:Receptors, Angiotensin / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000235:genetics; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D017931:DNA Primers; D005353:Fibronectins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D018808:Transcription Factor AP-1; D000804:Angiotensin II; D003609:Dactinomycin