Cyclooxygenase-2 Induction by Bradykinin in Human Pulmonary Artery Smooth Muscle Cells Is Mediated by the Cyclic AMP Response Element through a Novel Autocrine Loop Involving Endogenous Prostaglandin E2, E-prostanoid 2 (EP2), and EP4 Receptors

Abstract

Bradykinin (BK) is an important mediator in several inflammatory and vascular diseases that acts in part via induction of cyclooxygenase-2 (COX-2). The mechanisms involved in BK-mediated COX-2 induction are unclear.Here we characterized the transcriptional mechanisms involved in human pulmonary artery smooth muscle cells. BK stimulated the activity of a transiently transfected 966-bp (؊917 to ؉ 49) COX-2 promoter luciferase reporter construct. There was no reduction in BK-induced luciferase activity in cells transfected with COX-2 promoter constructs of 674, 407, 239, and 135 bp or constructs with mutated CCAAT/enhancer-binding proteinor NF-B-binding sites. In contrast luciferase activity was reduced in cells transfected with a 407-bp COX-2 promoter fragment containing a mutated cAMP response element (CRE)-binding site, suggesting that the CRE binding site is critical. Electrophoretic mobility shift assays using oligonucleotides specific for the CREbinding region of the COX-2 promoter and consensus oligonucleotides showed strong specific binding. Furthermore BK increased consensus cAMP-responsive luciferase reporter (p6CRE/luc)-mediated luciferase expression. CRE activation occurred by BK inducing cytosolic phospholipase A 2 -mediated arachidonic acid release and rapid prostaglandin E 2 (PGE 2 ) production, thereby increasing cAMP. Indomethacin inhibited BKinduced PGE 2 production, cAMP accumulation, and CRE/luc reporter and COX-2 promoter luciferase activity. Exogenous PGE 2 and EP2 (ONO-AE1 259) and EP4 (ONO-AE1 329) PGE 2 receptor agonists mimicked the effect of BK. Collectively these studies indicate that COX-2 induction by BK in human pulmonary artery smooth muscle cells is mediated by the CRE through a novel autocrine loop involving endogenous PGE 2 .

Bradykinin potentiates cytokine‐induced prostaglandin biosynthesis in osteoblasts by enhanced expression of cyclooxygenase 2, resulting in increased RANKL expression

“…Consistent with observations in other cell types (38,43), stimulation of B2 receptors significantly enhanced COX-2 mRNA in MG-63 cells and in mouse calvarial bones. In addition, this study was the first to show that a BK B1 receptor agonist significantly enhanced COX-2 mRNA in both the human osteoblastic cell line MG-63 and in mouse calvariae.…”

Endothelial Cell Confluence Regulates Cyclooxygenase-2 and Prostaglandin E2 Production That Modulate Motility

“…In addition to this, we find a positive feed-forward loop involving the prostanoid PGE 2 after mechanical disruption of endothelial cell monolayers that aids recovery of monolayer integrity. PGE 2 stimulates endothelial cell cyclooxygenase-2 expression at low nanomolar levels, as recently found for cyclooxygenase 2 accumulation in pulmonary artery smooth muscle cells after bradykinin stimulation (28). PGE 2 accumulated to levels (ϳ6 nM) sufficient to stimulate cyclooxygenase-2 expression after wounding confluent monolayers even in the absence of an exogenous source of arachidonate.…”

Bradykinin B2 Receptor Mediates NF-κB Activation and Cyclooxygenase-2 Expression via the Ras/Raf-1/ERK Pathway in Human Airway Epithelial Cells

“…In foreskin fibroblasts, COX-2 induction by IL-1␤ used the C/EBP-binding domain (45). In airway smooth muscle cells, BK-induced COX-2 expression was mediated by CCAAT/enhancer protein but not by NF-B or C/EBP, whereas NF-B was involved in IL-1␤-induced COX-2 expression (46). The results of this study showed that NF-B activation contributed to BK-induced COX-2 induction in A549 cells, and that the inhibitors of the NF-B-dependent signaling pathway, including PDTC and TPCK, inhibited BK-induced COX-2 expression.…”