Interleukin-1-induced interleukin-6 is required for the inhibition of proteoglycan synthesis by interleukin-1 in human articular cartilage.
Cartilage from normal controls, patients with osteoarthritis, and patients with rheumatoid arthritis produced no interleukin-6 (IL-6) in culture. However, IL-1 induced massive production of IL-6 (up to 135 ng/ml) in cartilage from all 3 sources, in a dose-dependent manner (in some cases, a peak value was reached). The levels of induced IL-6 were similar to those found in rheumatoid arthritis synovial fluid. At IL-1 concentrations that induced almost complete inhibition of proteoglycan (PG) synthesis, IL-6 production could still be increased considerably. Exogenous IL-6 inhibited PG synthesis by up to 25%. IL-1-induced inhibition of PG synthesis was reversed by antibodies against recombinant human IL-6. These results suggest that IL-6 is required for the IL-1-induced inhibition of PG synthesis.
Nietfeld
J J
JJ
Department of Rheumatology, University Hospital, Utrecht, The Netherlands.
Wilbrink
B
B
Helle
M
M
van Roy
J L
JL
den Otter
W
W
Swaak
A J
AJ
Huber-Bruning
O
O
D000328:Adult; D000367:Age Factors; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism*; D002675:Child, Preschool; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology / Q000502:physiology*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D010003:Osteoarthritis / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000494:pharmacology; D013582:Synovial Fluid / Q000378:metabolism
D007375:Interleukin-1; D015850:Interleukin-6; D011509:Proteoglycans; D011994:Recombinant Proteins