Cyclooxygenase-2-Derived E Prostaglandins Down-Regulate Matrix Metalloproteinase-1 Expression in Fibroblast-Like Synoviocytes via Inhibition of Extracellular Signal-Regulated Kinase Activation

Abstract

We examined the regulation of matrix metalloproteinase (MMP) production by mitogen-activated protein kinases and cyclooxygenases (COXs) in fibroblast-like synoviocytes (FLSCs). IL-1β and TNF-α stimulated FLSC extracellular signal-regulated kinase (ERK) activation as well as MMP-1 and -13 release. Pharmacologic inhibitors of ERK inhibited MMP-1, but not MMP-13 expression. Whereas millimolar salicylates inhibited both ERK and MMP-1, nonsalicylate COX and selective COX-2 inhibitors enhanced stimulated MMP-1 release. Addition of exogenous PGE1 or PGE2 inhibited MMP-1, reversed the effects of COX inhibitors, and inhibited ERK activation, suggesting that COX-2 activity tonically inhibits MMP-1 production via ERK inhibition by E PGs. Exposure of FLSCs to nonselective COX and selective COX-2 inhibitors in the absence of stimulation resulted in up-regulation of MMP-1 expression in an ERK-dependent manner. Moreover, COX inhibition sufficient to reduce PGE levels increased ERK activity. Our data indicate that: 1) ERK activation mediates MMP-1 but not MMP-13 release from FLSCs, 2) COX-2-derived E PGs inhibit MMP-1 release from FLSCs via inhibition of ERK, and 3) COX inhibitors, by attenuating PGE inhibition of ERK, enhance the release of MMP-1 by FLSC.

Prostaglandin E Receptor Type 4-associated Protein Interacts Directly with NF-κB1 and Attenuates Macrophage Activation

“…Consistent with our observations, PGE 2 /EP4-mediated inhibition of stimulus-induced MEK activation occurs in other cell types (45)(46)(47). We furnish here novel evidence supporting the involvement of EP4-EPRAP signaling in the suppression of MEK activation through inhibiting inducible p105 phosphorylation and degradation.…”

Helicobacter pylori Stimulates Gastric Epithelial Cell MMP-1 Secretion via CagA-dependent and -independent ERK Activation

“…Because 1) phosphorylated CagA activates host cell SHP-2 (11), and 2) SHP-2 expression knockdown by small interfering RNA abolishes ERK activation in AGS cells stably expressing an EPIYA-positive CagA (80), both CagA-induced ERK activation and MMP-1 secretion likely are SHP-2-mediated. That MEK inhibition also regulates ERK activity and MMP-1 expression in rheumatoid synovial fibroblasts (36) and osteoarthritis chondrocytes (81) indicates that ERK pathway regulation of MMP-1 secretion is a conserved signaling pathway in cells involved with inflammation and erosion. MEK inhibition also reduces ERK activation, MMP-1 secretion, and collagenolysis, in invasive melanoma cells embedded in Type I collagen matrices (53).…”

“…The cultures were incubated for the indicated times at 37°C, and supernatants collected, concentrated, and analyzed, as described (23). Adherent cells were washed 3 times with cold phosphate-buffered saline, lysed (20 mM Tris, pH 7.4, 1 mM EGTA, 2 mM sodium vanadate, 25 mM sodium fluoride, 0.5% (v/v) Triton X-100, 2 mM phenylmethylsulfonyl fluoride, 10 5 kallikrein units/ml aprotinin, and 10 g/ml each of chymostatin, antipain, and pepstatin) for 20 min at 4°C, as described (36), and lysates collected and used directly or frozen for further study.…”

“…Volume equivalents were assayed for MMP-1 by SDS-PAGE and immunoblotting with anti-MMP-1 antiserum (1:400). In each case, immunoblots were resolved by incubating with horseradish peroxidase-conjugated anti-rabbit antibody, imaged by chemiluminescence and autoradiography according to the manufacturer's instructions, and quantitated by densitometry (36).…”

“…However, ERK also can regulate inflammatory responses, including neutrophil adhesion and superoxide generation (35). In synovial fibroblasts, ERK activation mediates cytokine-and growth factor-stimulated MMP-1 secretion, enhancing tissue destruction in inflammatory arthritis (36). Although H. pylori stimulates ERK activation in gastric epithelial cells (37)(38)(39)(40)(41), the kinetics of ERK activation, as well as the role of CagA in this process, are not fully understood.…”