Inhibition of cytokine gene expression by sodium salicylate in a macrophage cell line through an NF-kappaB-independent mechanism.
Macrophage-derived cytokines and chemokines are involved at multiple steps of immune and inflammatory responses, and the transcriptional factor NF-kappaB appears to play a pivotal role in their coordinated upregulation. The anti-inflammatory agents salicylates have been proposed to act in part by inhibiting NF-kappaB. We have therefore studied the effects of sodium salicylate on lipopolysaccharide (LPS)-induced kappaB-binding activity and on cytokine and chemokine gene expression in the RAW264.7 murine macrophage cell line and compared them to those of an established NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC). PDTC (100 microM) completely abrogated LPS-induced kappaB-binding activity and also profoundly inhibited the induction of interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-10, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and MCP-1 and, to a lesser extent, leukemia inhibitory factor, RANTES, and IL-1Ra. In contrast, sodium salicylate (15 to 20 mM) had no effect on NF-kappaB activation but, nevertheless, suppressed several LPS-induced cytokine and chemokine genes to a degree similar to that obtained with PDTC. However, compared to PDTC, sodium salicylate caused significantly less inhibition of IL-1Ra and IL-10 gene expression after LPS stimulation. Neither LPS-induced MIP-1alpha, MIP-1beta, nor MIP-2 was significantly affected by PDTC or sodium salicylate, demonstrating that NF-kappaB is dispensable for the transcriptional regulation of these genes by LPS. In summary, these results suggest that both NF-kappaB-dependent and NF-kappaB-independent pathways are necessary for the induction by LPS of a complex cytokine and chemokine response. In the RAW264.7 macrophage cell line, suprapharmacological concentrations of sodium salicylate exert a potent inhibitory effect on LPS-induced cytokine gene induction but appear to accomplish this by interfering with NF-kappaB-independent pathways of activation.
Lemay
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Department of Medicine, Division of Nephrology, New England Medical Center, Boston, Massachusetts 02111, USA. serge.lemay@lan1.molonc.mcgill.ca
Lebedeva
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Singh
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D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002460:Cell Line; D018925:Chemokines / Q000235:genetics; D016207:Cytokines / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D011759:Pyrrolidines / Q000494:pharmacology; D012980:Sodium Salicylate / Q000494:pharmacology*; D013859:Thiocarbamates / Q000494:pharmacology
D000975:Antioxidants; D018925:Chemokines; D016207:Cytokines; D016298:Hematopoietic Cell Growth Factors; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011759:Pyrrolidines; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D012980:Sodium Salicylate