The immunomodulatory effects of acute and chronic alcohol use are characterized by impaired antigen-specific immune activation and by increased susceptibility to infections due to alterations in innate immune responses and inflammatory mediator production. The central feature of cellular responses to inflammatory and stress signals is the activation of the nuclear regulatory kappa B/Rel family of transcriptional factors via various surface receptor systems in immunocompetent cells. Activation of NF-kappa B, however, is regulated at multiple levels including I-kappa B degradation, nuclear translocation, and by interaction of NF-kappa B/Rel with other transcription factors. Data from our and other laboratories demonstrate that acute alcohol treatment inhibits activation and nuclear binding of the p65/p50 NF-kappa B functional heterodimer in human monocytes, a mechanism likely contributing to inhibition of pro-inflammatory cytokine production. Here we show that acute alcohol-mediated inhibition of NF-kappa B activation in various monocytic cells including human monocytes and murine macrophages. Inhibition of NF-kappa B activation by alcohol in monocytic cells was independent of I-kappa B alpha degradation. These acute-alcohol-induced changes in monocytic cells were different compared to T lymphocytes, both in Jurkat CD4 cells and peripheral human T cells, acute alcohol had a biphasic effect on TNF-alpha-induced NF-kappa B activation via an I-kappa B alpha-dependent mechanism. Inhibition of NF-kappa B activation by acute alcohol in LPS-activated human monocytes was associated with an increase in nuclear glucocorticoid receptor (GR) levels and reduced GR binding to the glucocorticoid response element (GRE). Together these findings support the hypothesis that in the presence of alcohol, nuclear interaction of NF-kappa B (p65) with glucocorticoid receptor and/or other transcription factors may contribute to the reduced NF-kappa B activation. In contrast to the inhibitory effects of acute alcohol on NF-kappa B activation in monocytic cells, chronic alcohol use and alcoholic hepatitis result in an augmentation of NF-kappa B activation and pro-inflammatory cytokine induction. These results suggest that the complex interactions of the NF-kappa B/Rel and related transcription factors including GR and heat-shock responses determine the level of activation of the immunocompetent cells in response to the challenge of acute and chronic alcohol use at the single cell level.

BACKGROUND: Acute alcohol treatment blocks inflammatory cytokines via inhibition of NF-kappaB in monocytes in the presence of ongoing IkappaBalpha degradation, suggesting regulation of NF-kappaB activation downstream of IkappaBalpha degradation. DNA binding of NF-kappaB has been suggested to be regulated by other nuclear regulatory factors, including the glucocorticoid receptor (GR). Here, we show for the first time that acute alcohol (25 mM) exposure modulates GR activation in monocytes. METHODS: Human peripheral blood monocytes were treated with lipopolysaccharide (LPS) in the presence or absence of alcohol (25 mM) for 1 hour. Nuclear GR levels were estimated by Western blotting and NFkappaB activation was studied in the same extracts by gel shift analysis (EMSA). Cells were stimulated with 1 microM of Dex to be used as positive control for GR activation. GR/GRE binding was also determined in nuclear extracts by EMSA. IkappaBalpha mRNA known to be induced by GR/GRE activation was studied in total RNA extracts by the SuperArray method (SuperArray Inc., Bethesda, MD). RESULTS: LPS is a potent inducer of GR nuclear translocation and GR binding to the glucocorticoid response element (GRE). Acute alcohol treatment both induced (p < 0.05) and augmented (p < 0.05) LPS-stimulated GR nuclear levels. However, alcohol inhibits LPS-induced (nonligand bound) GR/GRE binding activity in monocytes. This inhibition of GR transactivation by alcohol was further confirmed by decreased expression (40%) of a target gene, IkappaBalpha. Thus, alcohol treatment increases nonligand-bound nuclear GR, but inhibits its transactivation function. Ligand-induced GR/GRE binding was decreased in alcohol-treated monocytes. Inhibition of ligand-induced GR/GRE binding by alcohol exposure is likely due to cytoplasmic retention of the GR. CONCLUSIONS: Our results show that acute alcohol exposure inhibits GR in monocytes by differently affecting ligand- and nonligand-induced GR nuclear translocation. These data also suggest that acute alcohol regulates GR activation in monocytes concomitant to inhibition of NF-kappaB activation.