Chondrocalcin is internalized by chondrocytes and triggers cartilage destruction via an interleukin-1beta-dependent pathway.
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Date publication
octobre 2013
Auteurs
Membres identifiés du Cancéropôle Est :
Pr MAGDALOU Jacques, Pr MAINARD Didier, Dr VINCOURT Jean-Baptiste
Tous les auteurs :
Bantsimba-Malanda C, Cottet J, Netter P, Dumas D, Mainard D, Magdalou J, Vincourt JB
Lien Pubmed
Résumé
Chondrocalcin is among the most highly synthesized polypeptides in cartilage. This protein is released from its parent molecule, type II pro-collagen, after secretion by chondrocytes. A participation of extracellular, isolated chondrocalcin in mineralization was proposed more than 25 years ago, but never demonstrated. Here, exogenous chondrocalcin was found to trigger MMP13 secretion and cartilage destruction ex vivo in human cartilage explants and did so by modulating the expression of interleukin-1beta in primary chondrocyte cultures in vitro. Chondrocalcin was found internalized by chondrocytes. Uptake was found mediated by a single 18-mer peptide of chondrocalcin, which does not exhibit homology to any known cell-penetrating peptide. The isolated peptide, when artificially linked as a tetramer, inhibited gene expression regulation by chondrocalcin, suggesting a functional link between uptake and gene expression regulation. At the same time, the tetrameric peptide potentiated chondrocalcin uptake by chondrocytes, suggesting a cooperative mechanism of entry. The corresponding peptide from type I pro-collagen supported identical cell-penetration, suggesting that this property may be conserved among C-propeptides of fibrillar pro-collagens. Structural modeling localized this peptide to the tips of procollagen C-propeptide trimers. Our findings shed light on unexpected function and mechanism of action of these highly expressed proteins from vertebrates.
Référence
Matrix Biol. 2013 Oct-Nov;32(7-8):443-51