Activator protein-1 mediates shear stress-induced prostaglandin d synthase gene expression in vascular endothelial cells.
OBJECTIVE
We attempted to determine the molecular mechanism of fluid shear stress-induced lipocalin-type prostaglandin D synthase (l-PGDS) expression in vascular endothelial cells.


RESULTS
We examined the promoter region of the l-PGDS gene by loading laminar shear stress (20 dyne/cm2), using a parallel-plate flow chamber, on endothelial cells transfected with luciferase reporter vectors containing the 5'-flanking regions of the human l-PGDS gene. A deletion mutant analysis revealed that a shear stress-responsive element resided in the region between -2607 and -2523 bp. A mutation introduced into the putative binding site for activator protein-1 (AP-1) within this region eliminated the response to shear stress. In an electrophoretic mobility shift assay, shear stress stimulated nuclear protein binding to the AP-1 binding site, which was supershifted by antibodies to c-Fos and c-Jun. Shear stress elevated the c-Jun phosphorylation level in a time-dependent manner, similar to that of l-PGDS gene expression. SP600125, a c-Jun N-terminal kinase inhibitor, decreased the c-Jun phosphorylation, DNA binding of AP-1, and l-PGDS expression induced by shear stress. Additionally, an mRNA chase experiment using actinomycin D demonstrated that shear stress did not stabilize l-PGDS mRNA.


CONCLUSIONS
Shear stress induces l-PGDS expression by transcriptional activation through the AP-1 binding site.
Miyagi
Megumi
M
Department of Clinical Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Miwa
Yoshikazu
Y
Takahashi-Yanaga
Fumi
F
Morimoto
Sachio
S
Sasaguri
Toshiyuki
T
D024506:5' Flanking Region; D000818:Animals; D001158:Arteries / Q000166:cytology; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D054834:Lipocalins; D010766:Phosphorylation; D020871:RNA Stability / Q000502:physiology; D020218:Response Elements; D013314:Stress, Mechanical; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology; D014471:Umbilical Veins / Q000166:cytology
D054834:Lipocalins; D018808:Transcription Factor AP-1; D048031:JNK Mitogen-Activated Protein Kinases; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase