The mechanism of taurine chloramine inhibition of cytokine (interleukin-6, interleukin-8) production by rheumatoid arthritis fibroblast-like synoviocytes.
OBJECTIVE
Taurine chloramine (Tau-Cl) has been shown to inhibit the production of proinflammatory cytokines (interleukin-6 [IL-6] and IL-8) by fibroblast-like synoviocytes (FLS) isolated from rheumatoid arthritis (RA) patients. The present study was conducted to elucidate the mechanism of inhibitory action exerted by Tau-Cl.


METHODS
The effects of Tau-Cl on 1) the transcription of genes coding for IL-6 and IL-8, and 2) the activity of nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors, which are crucial for the transcription of these cytokine genes, were investigated in FLS isolated from the synovial tissue of RA patients. FLS were cultured in vitro for 3-6 passages and stimulated with recombinant human IL-1beta (1 ng/ml) in the presence of either Tau or Tau-Cl, which were added simultaneously with the stimulus at concentrations of 250 microM or 500 microM. The relative expression of IL-6 and IL-8 messenger RNA (mRNA) was evaluated after 4 hours of stimulation, using competitive reverse transcriptase-polymerase chain reaction. The DNA binding activity of NF-kappaB and AP-1 was examined 30 minutes and 2 hours after cell stimulation, respectively, using electromobility gel shift assay.


RESULTS
IL-1beta triggered a significant rise in the activity of transcription factors NF-kappaB and AP-1, followed by an elevation of cytokine IL-6 and IL-8 mRNA expression. Tau-Cl, but not Tau, reduced IL-1beta-triggered cytokine mRNA expression, exerting stronger inhibitory activity on the levels of IL-6 than on those of IL-8. Importantly, Tau-Cl also diminished the activity of NF-kappaB and, to a lesser extent, that of AP-1 transcription factor. Neither IL-1beta nor Tau-Cl affected the activity of octamer transcription factor 1.


CONCLUSIONS
Tau-Cl inhibition of IL-6 and IL-8 synthesis in FLS from RA patients results from the ability of this compound to diminish the activity of the major transcriptional regulators (NF-kappaB and AP-1), which subsequently reduces the transcription of these cytokine genes.
Kontny
E
E
Institute of Rheumatology, Warsaw, Poland.
Szczepańska
K
K
Kowalczewski
J
J
Kurowska
M
M
Janicka
I
I
Marcinkiewicz
J
J
Maśliński
W
W
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology*; D004268:DNA-Binding Proteins / Q000187:drug effects; D005260:Female; D005347:Fibroblasts / Q000166:cytology*; D051863:Host Cell Factor C1; D006801:Humans; D018836:Inflammation Mediators / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D016209:Interleukin-8 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D016328:NF-kappa B / Q000187:drug effects; D050811:Octamer Transcription Factor-1; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology*; D013654:Taurine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000187:drug effects; D014157:Transcription Factors / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects; D000093242:Interleukin-6 Inhibitors
D004268:DNA-Binding Proteins; D051863:Host Cell Factor C1; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D016328:NF-kappa B; D050811:Octamer Transcription Factor-1; D013654:Taurine; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D000093242:Interleukin-6 Inhibitors; C497692:HCFC1 protein, human; C494165:POU2F1 protein, human; C043410:N-chlorotaurine