Untitled

Abstract

The immediate-early cyclooxygenase-2 (COX-2) gene encodes an inducible prostaglandin synthase enzyme which is implicated in inflammatory and proliferative diseases. COX-2 is highly induced during cell activation by various factors, including mitogens, hormones and cytokines. Since pro-inflammatory cytokine IL-1beta has been shown to induce prostaglandin E2 (PGE2) release in human gingival fibroblasts (HGF), here we analyzed the effect of IL-1beta on the expression of COX-2 and the activation of NFkappaB in HGF. Northern hybridization analysis revealed that IL-1beta (200 pg/ml) increased the expression of COX-2 mRNA in HGF. The effect of IL-1beta was abrogated by herbimycin A, a protein tyrosine kinase inhibitor, and enhanced by orthovanadate, a protein tyrosine phosphatase inhibitor. IL-1beta-induced PGE2 release was blocked by the tyrosine kinase inhibitor and increased by the tyrosine phosphatase inhibitor. The results of transient transfection assays using chimeric constructs of the human COX-2 promoter (nt -1432 approximately +59) ligated to a luciferase reporter gene indicated that IL-1beta stimulated the transcriptional activity approximately 1.5-fold. Gel mobility shift assays with a radiolabelled COX-2-NFkappaB oligonucleotide (nts-223 to-214) revealed an increase in the binding of nuclear proteins from IL-1beta-stimulated HGF. This increase of DNA-protein complex formation induced by IL-1beta was blocked by herbimycin A and another tyrosine kinase inhibitor, genistein. These results suggest that NFkappaB is an important transcription factor for IL-1beta-induced COX-2 gene expression, and is involved in inducing COX-2 gene transcription through tyrosine phosphorylation in HGF.

[6]-Gingerol inhibits COX-2 expression by blocking the activation of p38 MAP kinase and NF-κB in phorbol ester-stimulated mouse skin

“…Since the induction of COX-2 is frequently regulated by NF-kB (Nakao et al, 2000;Lim et al, 2001;Surh et al, 2001), we attempted to examine the effects of [6]gingerol on TPA-stimulated DNA binding and transcriptional activity of NF-kB in mouse skin. For this Figure 2 Inhibitory effects of [6]-gingerol on phorbol esterinduced COX-2 expression in mouse skin.…”

Prostaglandin E2 Stimulates Bone Sialoprotein (BSP) Expression through cAMP and Fibroblast Growth Factor 2 Response Elements in the Proximal Promoter of the Rat BSP Gene

“…U0126 (5 M) was used to inhibit MAP kinase kinase activity (52). Sodium orthovanadate (50 M) and okadaic acid (50 nM) were used for tyrosine phosphatase and serine-threonine phosphatase inhibition, respectively (53,54). Forskolin (1 M) was used for activation of adenylate cyclase (45).…”

Cot Kinase Induces Cyclooxygenase-2 Expression in T Cells through Activation of the Nuclear Factor of Activated T Cells

“…Previous results indicate that Cot kinase increases interleukin-2 gene expression (14 -16) mainly by up-regulating the transcription driven by NF-B and the composite element NFAT-AP-1 of interleukin-2 promoter (16); Cot kinase also up-regulates the AP-1 response element of the collagenase promoter (12,14,16). It has been shown that COX-2 promoter contains binding sites for these transcription factors, acting as positive regulatory elements of COX-2 transcription in several cell types (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). However, we have shown here that activation of COX-2 promoter in T cells occurs in a NF-kB-independent manner, in agreement with previous results discarding a role of this transcription factor in this cell type.…”

“…This induction takes place at the transcriptional level and is mediated by two NFAT sites in the COX-2 promoter (21). Previous studies in different cells types (including vascular endothelial cells, lung epithelial cells, synoviocytes, pancreatic cells, gingival fibroblasts, and monocytes) have shown the importance of NF-B and AP-1 transcription factors in other cell types (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34).…”