The molecular mechanism of inhibition of interleukin-1 beta-induced cyclooxygenase-2 expression in human synovial cells by Tripterygium wilfordii Hook F extract
K. Maekawa et al., The molecular mechanism of inhibition of interleukin-1 beta-induced cyclooxygenase-2 expression in human synovial cells by Tripterygium wilfordii Hook F extract, INFLAMM RES, 48(11), 1999, pp. 575-581
Objective: Several extracts of Tripterygium wilfordii Hook F (TWHF) have be
en reported to be effective in patients with rheumatoid arthritis. We inves
tigated the effect of multi-glycosides of TWHF (GTW), a TWHF extract, on in
terleukin (TL)-1 beta-stimulated human rheumatoid synovial cells. Materials
and Methods. IL-1 beta-stimulated synovial cells were used to detect the e
ffects of GTW on cyclooxygenase (COX)-1 and COX-2 activities, expression of
COX protein and mRNA, and nuclear transcription factors in experiments usi
ng respective reporter plasmids.
Results: GTW inhibited prostaglandin E-2 production by IL-1 beta-stimulated
synovial cells in a concentration-dependent manner, and also inhibited COX
-2 protein and mRNA expression in a similar fashion to dexamethasone. Howev
er, GTW did not act as a glucocorticoid agonist. GTW repressed IL-1 beta-in
duced nuclear factor-kappa B activity, but did not have a significant influ
ence on activating protein-1 activity.
Conclusion: The anti-rheumatic effect of GTW or TWHF may be partly mediated
through the inhibition of prostaglandin E-2 production in human synovial c
ells due to suppression of COX-2 mRNA, possibly via inhibition of nuclear f
actor-kappa B activity.