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Integrin alpha1beta1 mediates collagen induction of MMP-13 expression in MC615 chondrocytes
Marie-Claire Ronzière1, Elisabeth Aubert-Foucher, Jérôme Gouttenoire
1Laboratoire de Biologie et Ingénierie du Cartilage, Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS/UCBL, IFR 128 BioSciences Lyon-Gerland, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
Abstract:
During endochondral ossification, type I collagen is synthesized by osteoblasts together with some hypertrophic chondrocytes. Type I collagen has also been reported to be progressively synthesized in degenerative joints. Because Matrix Metalloproteinase-13 (MMP-13) plays an active role in remodeling cartilage in fetal development and osteoarthritic cartilage, we investigated whether type I collagen could activate MMP-13 expression in chondrocytes. We used a well-established chondrocytic cell line (MC615) and we found that MMP-13 expression was induced in MC615 cells cultured in type I collagen gel. We also found that alpha1beta1 integrin, a major collagen receptor, was expressed by MC615 cells and we further assessed the role of alpha1beta1 integrin in conducting MMP-13 expression. Induction of MMP-13 expression by collagen was potently and synergistically inhibited by blocking antibodies against alpha1 and beta1 integrin subunits, indicating that alpha1beta1 integrin mediates the MMP-13-inducing cellular signal generated by three-dimensional type I collagen. We also determined that activities of tyrosine kinase and ERK and JNK MAP kinases were required for this collagen-induced MMP-13 expression. Interestingly, bone morphogenetic protein (BMP)-2 opposed this induction, an effect that may be related to a role of BMP-2 in the maintenance of cartilage matrix.
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