Effects of Concanavalin A on Chondrocyte Hypertrophy and Matrix Calcification

• Published in: The Journal of biological chemistry Vol. 272; no. 12; pp. 7833 - 7840
• Main Authors: Yan, Weiqun, Pan, Haiou, Ishida, Hideyuki, Nakashima, Kazuhisa, Suzuki, Fujio, Nishimura, Masahiro, Jikko, Akitoshi, Oda, Ryo, Kato, Yukio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 21.03.1997; American Society for Biochemistry and Molecular Biology
• Subjects: Alkaline Phosphatase - biosynthesis; Animals; Calcification, Physiologic; Cartilage - cytology; Cartilage - drug effects; Cartilage - enzymology; Cartilage - metabolism; Cell Movement; Cell Size; Cells, Cultured; Collagen - biosynthesis; Concanavalin A - pharmacology; DNA - metabolism; DNA Replication; Enzyme Induction; Growth Substances - pharmacology; Hormones - pharmacology; Hypertrophy; Male; Mannosides - pharmacology; Methylmannosides; Proteoglycans - biosynthesis; Rabbits; Receptors, Calcitriol - biosynthesis; Space life sciences; Uronic Acids - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.12.7833

Resting chondrocytes do not usually undergo differentiation to the hypertrophic stage and calcification. However, incubating these cells with concanavalin A resulted in 10-100-fold increases in alkaline phosphatase activity, binding of 1,25(OH)2-vitamin D3, type X collagen synthesis, 45Ca incorporation into insoluble material, and calcium content. On the other hand, other lectins tested (including wheat germ agglutinin, lentil lectin, pea lectin, phytohemagglutinin-L, and phytohemagglutinin-E) marginally affected alkaline phosphatase activity, although they activate lymphocytes. Methylmannoside reversed the effect of concanavalin A on alkaline phosphatase within 48 h. Concanavalin A did not increase alkaline phosphatase activity in articular chondrocyte cultures. In resting chondrocyte cultures, succinyl concanavalin A was as potent as concanavalin A in increasing alkaline phosphatase activity, the incorporation of [35S]sulfate, D-[3H]glucosamine, and [3H]serine into proteoglycans, and the incorporation of [3H]serine into protein, although concanavalin A, but not succinyl concanavalin A, induced a rapid change in the shape of the cells from flat to spherical. These findings suggest that concanavalin A induces a switch from the resting, to the growth-plate stage, and that this action of concanavalin A is not secondary to changes in the cytoskeleton. Chondrocytes exposed to concanavalin A may be useful as a novel model of endochondral bone formation.