Inhibition of tumor necrosis factor alpha-induced prostaglandin E2 production by the antiinflammatory cytokines interleukin-4, interleukin-10, and interleukin-13 in osteoarthritic synovial fibroblasts: distinct targeting in the signaling pathways.
OBJECTIVE
To investigate the effects of the antiinflammatory cytokines interleukin-4 (IL-4), IL-10, and IL-13 on tumor necrosis factor alpha (TNFalpha)-induced prostaglandin E2 (PGE2) release in the cellular signaling cascade on human osteoarthritis (OA) synovial fibroblasts.


METHODS
Human OA synovial fibroblasts were cultured to explore the impact of IL-4, IL-10, and IL-13 on TNFalpha binding to TNF receptors (TNFR), soluble TNFR (sTNFR), cytoplasmic phospholipase A2 (cPLA2), and cyclooxygenase-2 (COX-2) production, and on the binding activity of the transcription factors nuclear factor kappaB (NF-kappaB), CCAAT-enhancer binding protein (C/EBP), activator protein 2 (AP-2), and cyclic AMP response element-binding protein (CREB).


RESULTS
IL-4, IL-10, and IL-13 at 5 ng/ml dramatically reduced TNFalpha-induced PGE2 release by approximately 90% (P < 0.0001). IL-4 up-regulated the level of TNFalpha-induced TNFR by 47% (P < 0.06), while IL-10 down-regulated it by 71% (P < 0.02); IL-13 had no effect. Although statistical significance was not reached, all 3 cytokines up-regulated the basal level of sTNFR-55. IL-4 and IL-10, while not altering the basal level of sTNFR-75, significantly increased the TNFalpha-stimulated release of sTNFR-75. IL-4, IL-10, and IL-13 reduced the TNFalpha-induced COX-2 level, and IL-4 and IL-10 reduced the cPLA2 level. IL-4 had no effect on TNFalpha up-regulation of NF-kappaB, and a slight decrease was noted with IL-10 and IL-13 at the highest concentration used (5 ng/ml). IL-4 and IL-13 decreased the TNFa-induced C/EBP accumulation in a dose-dependent manner, while IL-10 up-regulated its basal level. AP-2 and CREB were not induced by TNFalpha.


CONCLUSIONS
The results indicate that these antiinflammatory cytokines reversed the TNFalpha-induced release of PGE2 by OA synovial fibroblasts, by acting at various levels of the TNFa-dependent signaling cascade. These data shed new light on the mechanisms by which these cytokines reduce inflammatory processes.
Alaaeddine
N
N
University of Montréal, and Centre Hospitalier de l'Université de Montréal, Quebec, Canada.
Di Battista
J A
JA
Pelletier
J P
JP
Kiansa
K
K
Cloutier
J M
JM
Martel-Pelletier
J
J
D015152:Blotting, Northern; D022762:CCAAT-Enhancer-Binding Proteins; D000242:Cyclic AMP / Q000276:immunology / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000276:immunology / Q000378:metabolism; D051546:Cyclooxygenase 2; D003593:Cytoplasm / Q000201:enzymology / Q000276:immunology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015232:Dinoprostone / Q000276:immunology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D006801:Humans; D016753:Interleukin-10 / Q000276:immunology / Q000378:metabolism; D018793:Interleukin-13 / Q000276:immunology / Q000378:metabolism; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D007378:Interleukins / Q000276:immunology / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins; D008875:Middle Aged; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010003:Osteoarthritis / Q000276:immunology / Q000378:metabolism*; D010741:Phospholipases A / Q000276:immunology / Q000378:metabolism; D054467:Phospholipases A2; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction / Q000276:immunology; D013583:Synovial Membrane / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology*
D022762:CCAAT-Enhancer-Binding Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D018793:Interleukin-13; D007378:Interleukins; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D012333:RNA, Messenger; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D015847:Interleukin-4; D000242:Cyclic AMP; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010741:Phospholipases A; D054467:Phospholipases A2; D015232:Dinoprostone