Affiliations: Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS‐UCB Lyon I, IFR128 Biosciences Lyon‐Gerland, 7 passage du Vercors, 69367 Lyon Cedex 07, France
Note: [] Address for correspondence: Dr. Daniel Herbage, Laboratory of Cartilage Biology and Engineering, IBCP, 7 Passage du Vercors, 69367 Lyon Cedex 07, France. Tel.: +33 (0)4 72 72 26 15; Fax: +33 (0)4 72 72 26 02; E‐mail: d.herbage@ibcp.fr.
Abstract: In osteoarthritic cartilage, chondrocytes are able to present heterogeneous cellular reactions with expression and synthesis of the (pro)collagen types characteristic of prechondrocytes (type IIA), hypertrophic chondrocytes (type X), as well as differentiated (types IIB, IX, XI, VI) and dedifferentiated (types I, III) chondrocytes. The expression of type IIA procollagen in human osteoarthritic cartilage support the assumption that OA chondrocytes reverse their phenotype towards a chondroprogenitor phenotype. Recently, we have shown that dedifferentiation of mouse chondrocytes induced by subculture was associated with the alternative splicing of type II procollagen pre‐mRNA with a switch from the IIB to the IIA form. In this context, we demonstrated that BMP‐2 favours expression of type IIB whereas TGF‐β1 potentiates expression of type IIA induced by subculture. These data reveal the specific capability of BMP‐2 to reverse the program of chondrocyte dedifferentiation. This interesting feature needs to be tested with human chondrocytes since cell amplification is required for the currently used autologous chondrocyte transplantation.
Keywords: Chondrocyte phenotype, type IIA and IIB procollagen, BMP‐2, TGF‐β1, cartilage repair
Journal: Biorheology, vol. 41, no. 3-4, pp. 535-542, 2004
