Activator Protein-1 Mediates Shear Stress–Induced Prostaglandin D Synthase Gene Expression in Vascular Endothelial Cells

Abstract

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. Methods and Results-We examined the promoter region of the L-PGDS gene by loading laminar shear stress (20 dyne/cm 2 ), using a parallel-plate flow chamber, on endothelial cells transfected with luciferase reporter vectors containing the 5Ј-flanking regions of the human L-PGDS gene. A deletion mutant analysis revealed that a shear stress-responsive element resided in the region between Ϫ2607 and Ϫ2523 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. applied in vitro prevents platelet aggregation 1 and induces endothelium-dependent arterial relaxation. 2 PGD 2 is metabolized to the PGJ 2 family, which includes PGJ 2 , ⌬ 12 -PGJ 2 , and 15-deoxy-⌬ 12,14 -PGJ 2 (15d-PGJ 2 ), without the requirement of specific enzymes. 3 The PGJ 2 family, particularly 15d-PGJ 2 , exhibits strong anti-inflammatory effects by inhibiting nuclear factor B 4 and IB kinase 5 or through the activation of a peroxisome proliferator-activated receptor-␥. 6 In macrophages, 15d-PGJ 2 inhibits inflammatory cytokine production, metalloproteinase-9 activation, and inducible NO synthase expression. 7,8 The PGJ 2 family strongly inhibits vascular smooth muscle cell proliferation and promotes smooth muscle cell differentiation. 9 -11 In vascular endothelial cells, 15d-PGJ 2 inhibits apoptotic cell death by upregulating the caspase inhibitor cellular inhibitor of apoptosis protein 1 (c-IAP1). 12 The majority of the effects induced by PGD 2 and the PGJ 2 family members appear to be anti-inflammatory, and therefore atheroprotective, because atherosclerosis is considered to be a chronic inflammation in vascular cells and tissues. 13 Lipocalin-type PGD synthase (L-PGDS) catalyzes the isomeric conversion of PGH 2 to PGD 2 . 14 In human cardiovascular tissues, the L-PGDS mRNA is most strongly expressed in the heart, where immunoreactivity of the enzyme is localized in the myocardial and endocardial cells. 15 Human aortic endothelial cells and intimal smooth muscle cells in vivo also stain positive for the L-PGDS mRNA by in situ hybridization. 16 Recent studies have suggested relationships between L-PGDS and cardiovascular diseases. For example, L-PGDS is secreted into the coronary circulation in angina patients. 15 Ele...

Functional TRPM7 Channels Accumulate at the Plasma Membrane in Response to Fluid Flow

“…The rapid time course for this response suggests that TRPM7 is among the first molecules to respond to shear stress. Most cellular events induced by shear stress, such as cytoskeletal remodeling 22,23 and changes in gene expression pattern, 24,25 occur in the time scale of minutes to hours.…”

Enhancement of prostaglandin D2 production through cyclooxygenase-2 and lipocalin-type prostaglandin D synthase by upstream stimulatory factor 1 in human brain-derived TE671 cells under serum starvation

“…The transcriptional regulatory mechanism of L-PGDS gene expression has been extensively studied in various cells under a variety of conditions (Fujimori, 2007). L-PGDS gene expression was enhanced in TE671 cells by some stresses such as nutrient depletion (White et al, 1997) and shear stress (Miyagi et al, 2005). However, the mechanism regulating the transcription of the L-PGDS gene under such conditions is still unknown.…”

Zebrafish and chicken lipocalin-type prostaglandin D synthase homologues: Conservation of mammalian gene structure and binding ability for lipophilic molecules, and difference in expression profile and enzyme activity

“…L-PGDS gene expression is regulated through some nuclear receptors such as thyroid hormone receptor (White et al, 1997;García-Fernández et al, 1998), glucocorticoid receptor (García-Fernández et al, 2000), and estrogen receptors (Otsuki et al, 2003). Moreover, its expression is regulated by Notch-Hes signal, interleukin-1β, and protein kinase C in brain-derived cells (Fujimori et al, 2003(Fujimori et al, , 2005, and is enhanced in vascular endothelial cells via the action of activator protein-1 (Miyagi et al, 2005).…”