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Differential effects of interferon‐γ and glucocorticoids on FcγR gene expression in murine macrophages
Author(s) -
Sivo Judit,
Politis Alexander D.,
Vogel Stefanie N.
Publication year - 1993
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.54.5.451
Subject(s) - interferon gamma , biology , messenger rna , glucocorticoid receptor , gene expression , microbiology and biotechnology , receptor , glucocorticoid , phagocytosis , endocrinology , cytokine , immunology , gene , biochemistry
Interferon‐γ (IFN‐γ) was shown previously to increase Feγ receptor (FcyR)‐mediated binding and phagocytosis of immunoglobulin G‐opsonized erythrocytes in mouse peritoneal exudate macrophages. Glucocorticoids potentiated this effect. We have extended these observations to an investigation of the effects of IFN‐γ and glucocorticoids on steady‐state mRNA levels of the three FcyR genes expressed on murine macrophages: FcyRI, FcγRII, and FcγRIIIα. FcγRI mRNA was present at a barely detectable level in unstimulated cells but was induced 5‐ to 10‐fold by IFN‐γ. FcγRIIIα mRNA was expressed constitutively and was induced significantly but very modestly (1.5‐fold) by IFN‐γ. FcγRII mRNA also exhibited high constitutive expression, but it was not altered by IFN‐γ treatment. Dexamethasone (DEX) significantly increased the expression of IFN‐γ‐induced FcγRI mRNA but had no effect on the expression of FcγRII or FcγRIIIa transcripts in untreated or IFN‐ γ‐treated cells. The effect of DEX on FcγRI mRNA was seen after about 10 h of simultaneous treatment with IFN‐γ, was dose‐dependent, and was glucocorticoid specific. DEX did not modulate the rate of decay of the FcγRI mRNA, suggesting that the up‐regulatory effect of DEX may occur, in part, at the level of transcription. In the same culture system, the steady‐state level of IFN‐ γ‐induced Ia mRNA was concurrently inhibited by DEX. The up‐regulation of the IFN‐γ‐induced high‐affinity FcγRI mRNA, the failure to modulate the expression of the two low‐affinity FcγR mRNA species, and the down‐ regulation of IFN‐γ‐induced la mRNA by DEX in the same cell population illustrate the diverse, gene‐specific influence of glucocorticoids on the expression of IFN‐ γ‐inducible genes.