Effects of concanavalin A on chondrocyte hypertrophy and matrix calcification.
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.
Yan
W
W
Department of Biochemistry, Hiroshima University, Hiroshima 734, Japan.
Pan
H
H
Ishida
H
H
Nakashima
K
K
Suzuki
F
F
Nishimura
M
M
Jikko
A
A
Oda
R
R
Kato
Y
Y
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D002113:Calcification, Physiologic; D002356:Cartilage / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D002465:Cell Movement; D048429:Cell Size; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis; D003208:Concanavalin A / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D004790:Enzyme Induction; D006133:Growth Substances / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology; D006984:Hypertrophy; D008297:Male; D008362:Mannosides / Q000494:pharmacology; D008766:Methylmannosides; D011509:Proteoglycans / Q000096:biosynthesis; D011817:Rabbits; D018167:Receptors, Calcitriol / Q000096:biosynthesis; D014574:Uronic Acids / Q000378:metabolism
D006133:Growth Substances; D006728:Hormones; D008362:Mannosides; D008766:Methylmannosides; D011509:Proteoglycans; D018167:Receptors, Calcitriol; D014574:Uronic Acids; D003208:Concanavalin A; C008466:methylmannoside; D003094:Collagen; D004247:DNA; D000469:Alkaline Phosphatase