Effects of recombinant human osteogenic protein 1 on the production of proteoglycan, prostaglandin E2, and interleukin-1 receptor antagonist by human articular chondrocytes cultured in the presence of interleukin-1beta.
OBJECTIVE
Recombinant human osteogenic protein 1 (OP-1) is an effective stimulator of human cartilage 35S-proteoglycan synthesis. The present study was conducted to determine whether stimulation of human articular chondrocytes with OP-1 can help overcome interleukin-1beta (IL-1beta)-induced suppression of 35S-proteoglycan synthesis.


METHODS
Human articular chondrocytes in alginate beads were maintained for 3 days in the absence (control) or presence of IL-1beta at 0.1-100 pg/ml with or without OP-1 at 50 ng/ml, in medium containing 10% fetal bovine serum (FBS). Incorporation of 35S-sulfate into proteoglycans was quantified during the last 4 hours of culture and reported as counts per minute per microg DNA. Release of interleukin-1 receptor antagonist (IL-1Ra) and prostaglandin E2 into the medium was monitored by immunoassay.


RESULTS
IL-1beta at 10 pg/ml caused a 60% decrease in 35S-proteoglycan synthesis. This could be blocked by including 500 ng/ml IL-1Ra in the medium. The presence of 50 ng/ml OP-1 in the IL-1beta-containing medium was effective in restoring 35S-proteoglycan synthesis to the level of that found in cultures not treated with IL-1beta. The restorative effects of OP-1 and IL-1Ra were cumulative. The rate of release of prostaglandin E2 and IL-1Ra into the medium was not affected by the presence of OP-1.


CONCLUSIONS
Treatment of human articular chondrocytes with OP-1 cultured in the presence of FBS is effective in overcoming the down-regulation of proteoglycan synthesis induced by low doses of IL-1beta.
Huch
K
K
Rush Medical College at Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
Wilbrink
B
B
Flechtenmacher
J
J
Koepp
H E
HE
Aydelotte
M B
MB
Sampath
T K
TK
Kuettner
K E
KE
Mollenhauer
J
J
Thonar
E J
EJ
D000293:Adolescent; D000328:Adult; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002675:Child, Preschool; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis*; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D006801:Humans; D007223:Infant; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D011509:Proteoglycans / Q000096:biosynthesis*; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000494:pharmacology; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta
C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D011509:Proteoglycans; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins; D016212:Transforming Growth Factor beta; D015232:Dinoprostone