OBJECTIVE: In osteoarthritic (OA) synovial fluid, many proinflammatory cytokines coexist and stimulate chondrocytes. As interleukin 17 (IL-17) is a catabolic cytokine, we explored its effects on collagenase-3 production. In a comparative manner we identified IL-17 and IL-1beta induced transcription factors mediating upregulation of this enzyme's production. METHODS: Collagenase-3 levels were determined by ELISA. Transfection experiments of human OA chondrocytes were performed, with the plasmids -1599CAT and -133CAT consisting of 1.6 kb and the first proximal 133 bp containing polyomavirus enhancer A-3 (PEA-3), activating protein-1 (AP-1), and TATA box of the human collagenase-3 promoter, respectively. Electrophoretic mobility shift assays were done with the AP-1 and PEA-3 oligonucleotides derived from the human collagenase-3 promoter sequence. Supershift assays were carried out with the specific antibodies against the Jun and Fos proteins. RESULTS: IL-17 induced collagenase-3 expression and synthesis, with an EC50 at 10 ng/ml. Transfection experiments with wild-type -1599CAT and -133CAT and their mutated AP-1 or PEA-3 derivatives revealed that the AP-1 site was essential for basal and proinflammatory cytokine induced collagenase-3 promoter activity, whereas the PEA-3 motif exerted a cooperative effect. Of note, in OA chondrocytes, IL-17 and IL-1beta induced collagenase-3 production through AP-1 occurred with differential protein complexes: IL-17 stimulation resulted in FosB activation, while IL-1beta stimulated c-Fos. Data showed a strong activation of JunB only in cells showing a higher collagenase-3 basal level and low cytokine (IL-17 and IL-1beta) inducibility, suggesting this transcription factor protein acts as a negative regulator. CONCLUSION: We demonstrated that IL-17 and IL-1beta induced collagenase-3 production in OA chondrocytes mainly through AP-1 mediated transcriptional activity but with differential protein complexes, suggesting that some AP-1 proteins play a pivotal role in the different cytokine responses in terms of collagenase-3 production. Our data might suggest that JunB protein plays a rate-limiting step in cytokine induced collagenase-3 production in OA chondrocytes.
OBJECTIVE: In osteoarthritic (OA) synovial fluid, many proinflammatory cytokines coexist and stimulate chondrocytes. As interleukin 17 (IL-17) is a catabolic cytokine, we explored its effects on collagenase-3 production. In a comparative manner we identified IL-17 and IL-1beta induced transcription factors mediating upregulation of this enzyme's production. METHODS:Collagenase-3 levels were determined by ELISA. Transfection experiments of human OA chondrocytes were performed, with the plasmids -1599CAT and -133CAT consisting of 1.6 kb and the first proximal 133 bp containing polyomavirus enhancer A-3 (PEA-3), activating protein-1 (AP-1), and TATA box of the humancollagenase-3 promoter, respectively. Electrophoretic mobility shift assays were done with the AP-1 and PEA-3oligonucleotides derived from the humancollagenase-3 promoter sequence. Supershift assays were carried out with the specific antibodies against the Jun and Fos proteins. RESULTS:IL-17 induced collagenase-3 expression and synthesis, with an EC50 at 10 ng/ml. Transfection experiments with wild-type -1599CAT and -133CAT and their mutated AP-1 or PEA-3 derivatives revealed that the AP-1 site was essential for basal and proinflammatory cytokine induced collagenase-3 promoter activity, whereas the PEA-3 motif exerted a cooperative effect. Of note, in OA chondrocytes, IL-17 and IL-1beta induced collagenase-3 production through AP-1 occurred with differential protein complexes: IL-17 stimulation resulted in FosB activation, while IL-1beta stimulated c-Fos. Data showed a strong activation of JunB only in cells showing a higher collagenase-3 basal level and low cytokine (IL-17 and IL-1beta) inducibility, suggesting this transcription factor protein acts as a negative regulator. CONCLUSION: We demonstrated that IL-17 and IL-1beta induced collagenase-3 production in OA chondrocytes mainly through AP-1 mediated transcriptional activity but with differential protein complexes, suggesting that some AP-1 proteins play a pivotal role in the different cytokine responses in terms of collagenase-3 production. Our data might suggest that JunB protein plays a rate-limiting step in cytokine induced collagenase-3 production in OA chondrocytes.
Authors: Joel A Mathews; Nandini Krishnamoorthy; David I Kasahara; John Hutchinson; Youngji Cho; Jeffrey D Brand; Alison S Williams; Allison P Wurmbrand; Luiza Ribeiro; Frank Cuttitta; Mary E Sunday; Bruce D Levy; Stephanie A Shore Journal: Am J Respir Cell Mol Biol Date: 2018-03 Impact factor: 6.914
Authors: Ellen M Moran; Ronan Mullan; Jennifer McCormick; Mary Connolly; Owen Sullivan; Oliver Fitzgerald; Barry Bresnihan; Douglas J Veale; Ursula Fearon Journal: Arthritis Res Ther Date: 2009-07-23 Impact factor: 5.156