Details

Autor(en) / Beteiligte

• Radons, Jürgen
• Bosserhoff, Anja
• Grässel, Susanne
• Falk, Werner
• Schubert, Thomas

Titel

p38MAPK mediates IL-1-induced down-regulation of aggrecan gene expression in human chondrocytes

Ist Teil von

• International journal of molecular medicine, 2006-04, Vol.17 (4), p.661-668

Ort / Verlag

Greece: D.A. Spandidos

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• The pleiotropic cytokine interleukin 1 (IL-1) is considered to be the principal inducer of mediators of cartilage degradation in both, osteoarthritis (OA) and rheumatoid arthritis (RA). IL-1 activates numerous signaling pathways involved in cartilage destruction and dedifferentiation of chondrocytes. In this study, we analyzed expression and functional effects of IL-1 in human chondrocytes. We found an IL-1-induced reduction in the expression of the cartilage specific proteoglycan aggrecan as an indicator for the IL-1-mediated dedifferentiation of chondrocytes. To block the IL-1-induced signaling pathways specifically, we incubated human chondrocytes and cartilage explants with IL-1 in the presence of different signal transduction inhibitors and analyzed their effect on aggrecan mRNA expression and IL-6 secretion. IL-6 has been found to act synergistically in the IL-1-induced suppression of the proteoglycan synthesis in chondrocytes. Our results led to the identification of p38MAPK and/or PI3K/JNK as being crucial for IL-1-induced IL-6 secretion by chondrocytes. IL-1-induced down-regulation of aggrecan expression was found to be mediated by p38MAPK and/or ERK1/2. The identification and characterization of these signaling pathways will enable us to develop new modulation strategies for therapeutic use in inflammatory joint diseases.