PGE2 inhibits MMP expression by suppressing MKK4-JNK MAP kinase-c-JUN pathway via EP4 in human articular chondrocytes.

Prostaglandin E2 (PGE2) is one of pro-inflammatory mediators. PGE2 maintains the homeostasis of many organs including articular cartilage, and a previous report showed that continuous inhibition of PGE2 accelerates the progression of osteoarthritis (OA). While PGE2 inhibits matrix metalloprotease (MMP) expression in several types of cells, little is known on direct effects of PGE2 on MMP expression in articular chondrocytes.

Hyaluronan inhibits IL-1beta-stimulated collagenase production via down-regulation of phosphorylated p38 in SW-1353 human chondrosarcoma cells.

We investigated the intracellular mechanism for the inhibitory effects of hyaluronan (HA) on interleukin-1beta (IL-1beta)-stimulated collagenase-1 and -3 (matrix metalloproteinases (MMPs)-1 and -13) production in a human chondrosarcoma cell line, SW-1353. MMPs-1 and -13 were induced by IL-1beta at 2 ng/ml in SW-1353 cells for 48 h. HA of 800 kDa, which is used clinically, significantly suppressed IL-1beta-stimulated production of MMPs-1 and -13 by immunoblotting.

Induction of apoptosis by anti-CD44 antibody in human chondrosarcoma cell line SW1353.

Because chondrosarcoma is resistant to chemotherapy and ionizing radiation, the primary treatment of chondrosarcoma is surgical resection. Effective chemotherapeutic agents for chondrosarcoma are necessary. Although there is evidence that CD44 is involved in apoptosis susceptibility in several cell types, the effectiveness of anti-CD44 treatment on chondrosarcoma has never been studied.

Requirement of mitogen-activated protein kinase for collagenase production by the fibronectin fragment in human articular chondrocytes in culture.

Fibronectin fragments have been shown to up-regulate matrix metalloproteinase production in chondrocytes. We investigated the roles of mitogen-activated protein kinase (MAPK) pathways activated by the COOH-terminal heparin-binding fibronectin fragment (HBFN-f) in collagenase production by human chondrocytes in culture. In articular cartilage explant culture, HBFN-f stimulated type II collagen cleavage by collagenase in association with increased secretion of MMP-1 and MMP-13.

Lectin-like oxidized low-density lipoprotein receptor 1 mediates matrix metalloproteinase 3 synthesis enhanced by oxidized low-density lipoprotein in rheumatoid arthritis cartilage.

Objective: To investigate for the presence of oxidized low-density lipoprotein (ox-LDL) and lectin-like oxidized LDL receptor 1 (LOX-1) in cartilage specimens from rheumatoid arthritis (RA) joints and to determine whether the interaction of ox-LDL with LOX-1 can induce matrix metalloproteinase 3 (MMP-3) in articular cartilage explant culture.

Methods: Human articular cartilage specimens obtained from patients with RA, osteoarthritis (OA), and femoral neck fractures were examined for LOX-1 and ox-LDL by confocal fluorescence microscopy. The association between ox-LDL and LOX-1 was evaluated by immunofluorescence analysis.

Inhibition of interleukin-1beta-stimulated production of matrix metalloproteinases by hyaluronan via CD44 in human articular cartilage.

Objective: To investigate the mechanism of the inhibitory action of hyaluronan (HA) on interleukin-1beta (IL-1beta)-stimulated production of matrix metalloproteinases (MMPs) in human articular cartilage.

Methods: IL-1beta was added to normal and osteoarthritic (OA) human articular cartilage in explant culture to stimulate MMP production. Articular cartilage was incubated or preincubated with a clinically used form of 800-kd HA to assess its effect on IL-1beta-induced MMPs.

Hyaluronan inhibits matrix metalloproteinase-1 production by rheumatoid synovial fibroblasts stimulated by proinflammatory cytokines.

Objective: To study the inhibitory effects of hyaluronan (HA) on the production of matrix metalloproteinase-1 (MMP-1) by rheumatoid synovial fibroblasts (RSF) stimulated by proinflammatory cytokines, tumor necrosis factor-a (TNF-a), and interleukin-1beta (IL-1beta).

Methods: HA of various sizes at various concentrations was added to monolayer cultures of RSF in the presence of TNF-a or IL-1beta, with or without pretreatment with a monoclonal antibody against CD44, OS/37. Concentrations of MMP-1 in cell lysates and conditioned media and of CD44 on RSF were assayed by immunoblotting.