title: Dexamethasone antagonizes IL-4 and IL-10-induced release of IL-1RA by monocytes but augments IL-4-, IL-10-, and TGF-beta-induced suppression of TNF-alpha release.
abstract: The activities of monocyte-derived tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta are potentially modified by IL-1RA and soluble receptors for TNF (sTNF-R), which are themselves monocyte products. IL-4, IL-10, TGF-beta, and glucocorticoids (GC) all suppress the lipopolysaccharide (LPS)-stimulated release of TNF-alpha and IL-1beta but vary in their effects on IL-1RA and sTNF-R. This raises the prospect of interactions between the cytokines and glucocorticoids, which may be antagonistic or additive on IL-1 and TNF activity. We, therefore, studied the interactions of the GC dexamethasone (Dex) with IL-4, IL-10, and transforming growth factor (TGF)-beta on the release of TNF-alpha and IL-1RA by human monocytes and the monocytic THP-1 cell line. Low concentration of Dex (10(-8)-10(-7)M) acted additively with low concentrations of IL-4 (0.01-1 ng/ml), IL-10 (0.01-0.1 U/ml), or TGF-beta (0.01-1 ng/ml) to profoundly suppress LPS-stimulated release of TNF-alpha by whole blood and, to a lesser degree, THP-1 cells. Dex also suppressed spontaneous release of IL-1RA from PBMC and THP-1 cells, whereas IL-4 and IL-10, but not TGF-beta, stimulated release. Dex antagonized the enhanced release in IL-4 and IL-10-stimulated cultures. The capacity to stimulate release of IL-1RA may contribute to the anti-inflammatory potential of IL-4 and IL-10 in monocyte/macrophage-mediated disease. GC, therefore, do not uniquely enhance the suppressive functions of IL-4 and IL-10 on monokine activity. The therapeutic benefit of combinations of GC and IL-4, IL-10 or TGF-beta in disease may depend on the roles of the individual monokines and antagonists in pathogenesis.
authors.affiliation: Department of Pharmacology, University of Western Australia.
authors.forename: D A
authors.initials: DA
authors.lastname: Joyce
authors.forename: J H
authors.initials: JH
authors.lastname: Steer
authors.forename: A
authors.initials: A
authors.lastname: Kloda
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D011994:Recombinant Proteins / Q000378:metabolism; D012016:Reference Values; D012795:Sialoglycoproteins / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D005938:Glucocorticoids; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D008070:Lipopolysaccharides; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D015847:Interleukin-4; D003907:Dexamethasone