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Synergistic induction of matrix metalloproteinase 1 by interleukin-1? and oncostatin M in human chondrocytes involves signal transducer and activator of transcription and activator protein 1 transcription factors via a novel mechanism

2001; Wiley; Volume: 44; Issue: 10 Linguagem: Inglês

10.1002/1529-0131(200110)44

1529-0131

J. Catterall, S. Carr�re, P. J. T. Koshy, B. A. Degnan, W. D. Shingleton, Constance Brinckerhoff, Joni L. Rutter, T. E. Cawston, Andrew D. Rowan,

Chemokine receptors and signaling

To investigate the mechanism of interleukin-1alpha (IL-1alpha) and oncostatin M (OSM) synergistic regulation of matrix metalloproteinase 1 (MMP-1) in human chondrocytes.Using an immortalized human chondrocyte cell line (T/C28a4), we investigated regulation of the MMP-1 gene. Northern blotting and flow cytometric analysis were used to assess changes in receptor, MMP-1, and c-fos expression. Transient transfections using MMP-1 promoter/luciferase constructs, electrophoretic mobility shift assay, and site-directed mutagenesis were used to investigate MMP-1 promoter activation.We found no alteration in the expression of receptors used by these cytokines after stimulation with IL-1alpha/OSM. Using MMP-1 promoter/luciferase reporter constructs, we found that the proximal (-517/+63) region of the MMP-1 promoter was sufficient to support a synergistic activation. A role for activated signal transducers and activators of transcription (STAT-3) was demonstrated, although no binding of STAT-3 to the MMP-1 promoter was found. However, constitutive binding of activator protein 1 (AP-1) was detected, and changes in c-fos expression could modulate promoter activity.Since no changes in receptor expression were observed, receptor modulation cannot account for the IL-1alpha/OSM synergy observed. Instead, the interplay of various intracellular signaling pathways is a more likely explanation. STAT activation is required, but STAT proteins do not interact directly with the MMP-1 promoter. We propose that activated STATs stimulate c-fos expression, and changes in expression of the AP-1 components regulate MMP-1 expression. We highlight a new mechanism for MMP-1 regulation in human chondrocytes that could provide potential new therapeutic targets.