Interleukin-1 beta induces synthesis and secretion of interleukin-6 in human chondrocytes.
Increased concentrations of interleukin-6 (IL-6) have been found in the synovial fluid of patients with osteoarthritis, rheumatoid arthritis and crystal-related joint diseases. It is therefore of great interest to identify the cells responsible for the production of IL-6, and to investigate whether IL-6 plays a role in the pathogenesis of degenerative or inflammatory joint diseases. Here we show that human interleukin-1 beta (IL-1 beta) induces IL-6 synthesis and secretion in differentiated human chondrocytes. In organ cultures resembling closely the in vivo system 10(6) chondrocytes incubated with 100 units of interleukin-1 beta per ml of medium led to the release of 6 X 10(3) units of IL-6 within 24 h. Chondrocytes cultured in agarose or as monolayers similarly incubated with IL-1 beta produced even higher amounts of IL-6: 70 X 10(3) units per 10(6) cells within 24 h. The induction of IL-6 synthesis by IL-1 beta was also shown at the mRNA level. IL-6 secreted by stimulated chondrocytes showed heterogeneity upon Western blot analysis.
Bender
S
S
Institut für Biochemie, RWTH Aachen, FRG.
Haubeck
H D
HD
Van de Leur
E
E
Dufhues
G
G
Schiel
X
X
Lauwerijns
J
J
Greiling
H
H
Heinrich
P C
PC
D000328:Adult; D015152:Blotting, Northern; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology
D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D011994:Recombinant Proteins