Release of cell surface proteoglycan from chondrocytes by interleukin-1.
A cell culture model was developed to assess factors that can protect cartilage from recombinant human interleukin-1 alpha (IL-1)-induced breakdown. IL-1 (0.01-10 ng/ml) caused a dose-dependent release of cell surface proteoglycan into the medium of bovine and rabbit articular chondrocytes. Sulfated glycosaminoglycan (S-GAG) was detected in the medium and on the cell surface by a dimethlymethylene blue assay. The redistribution of the cell surface S-GAG to the medium compartment required protein synthesis because it was inhibited by cycloheximide and was time-dependent (> 5 h). Although the release was most likely due to de novo synthesis of proteases, standard protease inhibitors failed to prevent the release even when used in combination. TGF-beta and IGF-I increased the amount of S-GAG in both the medium and cell surface compartments, but did not protect from IL-1-induced release. This method has an advantage over a cartilage model of IL-1-induced matrix release because the drug and cytokine exposure time is reduced and the variability is less.
Goldberg
R L
RL
Research Department, CIBA-GEIGY Corporation, Summit, NJ 07901.
Spirito
S
S
Doughty
J R
JR
Di Pasquale
G
G
D000818:Animals; D001550:Benzamidines / Q000494:pharmacology; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006025:Glycosaminoglycans / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D011509:Proteoglycans / Q000378:metabolism*; D011817:Rabbits; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D001550:Benzamidines; D006025:Glycosaminoglycans; D007375:Interleukin-1; D011509:Proteoglycans; D016212:Transforming Growth Factor beta; C013786:A73025; D007334:Insulin-Like Growth Factor I; D003513:Cycloheximide; C032157:benzamidine; D005033:Ethylmaleimide