Glucocorticoid receptor (GR) beta has intrinsic, GRalpha-independent transcriptional activity.

The human glucocorticoid receptor (GR) gene produces C-terminal GRbeta and GRalpha isoforms through alternative use of specific exons 9beta and alpha, respectively. We explored the transcriptional activity of GRbeta on endogenous genes by developing HeLa cells stably expressing EGFP-GRbeta or EGFP. Microarray analyses revealed that GRbeta had intrinsic gene-specific transcriptional activity, regulating mRNA expression of a large number of genes negatively or positively. Majority of GRbeta-responsive genes was distinct from those modulated by GRalpha, while GRbeta and GRalpha mutually modulated each other's transcriptional activity in a subpopulation of genes. We did not observe in HCT116 cells nuclear translocation of GRbeta and activation of this receptor by RU 486, a synthetic steroid previously reported to bind GRbeta and to induce nuclear translocation. Our results indicate that GRbeta has intrinsic, GRalpha-independent, gene-specific transcriptional activity, in addition to its previously reported dominant negative effect on GRalpha-induced transactivation of GRE-driven promoters.

Major depression is associated with significant diurnal elevations in plasma interleukin-6 levels, a shift of its circadian rhythm, and loss of physiological complexity in its secretion: clinical implications.

BACKGROUND: Major depressive disorder (MDD) is associated with increased risk for premature coronary heart disease and bone loss. Single time measurements of plasma IL-6, a good predictor of future risk for both cardiovascular disease and osteoporosis, revealed significant elevations in depressed patients. The objective of this study was to rigorously compare plasma IL-6 levels, measured over 24 h, in MDD patients and healthy controls. Given the activating role of IL-6 on the hypothalamic-pituitary-adrenal (HPA) axis, and the relevance of its dysregulation in MDD, we also analyzed the relations between IL-6 and cortisol levels. METHODS: We studied nine patients and nine controls, individually matched by gender, age (+/-5 yr), body mass index (+/-2 kg/m2), and menstrual cycle phase. Diagnosis of MDD was confirmed by structured clinical interview based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I diagnostic criteria. Self-reported mood ratings were assessed by multiple visual analog scales. The rhythmicity and complexity of IL-6 and cortisol secretion were tested by cosinor analyses, approximate entropy (ApEn) and cross-ApEn algorithms. RESULTS: MDD patients had significant mean IL-6 elevations from 1000-1200 h and at 1500 h (P ranging from <0.05 to <0.01) vs. controls. In addition, in MDD, the circadian rhythm of IL-6 was shifted by 12 h, and its physiological complexity was reduced, with no difference in the cross-ApEn of IL-6 and cortisol between the two groups, and significant time-lagged correlations only in the controls. IL-6 levels correlated significantly with mood ratings. CONCLUSIONS: We report profound morning elevations of plasma IL-6 and a reversal of its circadian rhythm in MDD patients, in the absence of hypercortisolism. These findings may be relevant to the increased risk for coronary heart disease and bone loss in MDD.

Mechanisms of alcohol-mediated CD4+ T lymphocyte death: relevance to HIV and HCV pathogenesis.

Clinical and experimental studies have demonstrated that excessive alcohol consumption can result in impairment of the immune system, and can impact several immune functions including immune tolerance and host defense against opportunistic infections, and development of certain tumors. Although multiple factors are involved in the effects of ethanol on the immune system, several studies implicate chronic activation of immune cells and impairment of thymus-derived lymphocytes (T lymphocytes). Helper CD4+ T lymphocytes are the central regulators of the immune system and depletion of these lymphocytes is a major contributing factor in ethanol-induced immune dysfunction and exacerbation of HIV and/or HCV pathogenesis. However, the mechanisms involved in the ethanol induced CD4+ T cell depletion have only recently begun to be elucidated. Our work demonstrates that exposure of human CD4+ T cells to physiologically relevant concentrations of ethanol leads to the (i) enhanced activation of TNFalpha-inducible NFkappaB, the transcriptional regulator of the Fas promoter and ii) increased susceptibility to Fas-and activation-induced apoptotic death via augmentation of caspase 3 activity. Work done by us, and others, on the effects of ethanol on CD4+ T cell function and survival strongly suggests that alcohol plays a significant role as a co-factor in HIV and/or HCV pathogenesis.

Ethanol enhances activation-induced caspase-3 dependent cell death in T lymphocytes.

BACKGROUND: Clinical and experimental studies have shown that an important deleterious consequence of excessive alcohol consumption is immunosuppression, specifically, a depletion in the mature CD4+ T-cell population. A predominant mechanism involved in T-cell depletion is activation-induced cell death (AICD). Although it is well documented that ethanol intake can cause depletion of CD4+ T cells, the mechanism of how alcohol mediates its effects is unclear. METHODS: The results were based on data from three separate experiments presented as mean +/- standard deviation (SD). Jurkat CD4+ T cells and peripheral blood lymphocytes were treated with 25 mM of ethanol (12-18 hr), followed by stimulation with mitogens Conconavalin A (5 microg/ml) and Phytohemmaglutinin (1 microg/ml) or T-cell receptor ligation (anti-CD3 antibody (5 microg/ml)) for 6 hr, and then harvested for measurement. The apoptotic cell death markers measured include cell viability, Caspase-3-like activity, and DNA fragmentation. RESULTS: We demonstrate that alcohol pretreatment enhances AICD of Jurkat CD4+ T cells and peripheral blood lymphocytes upon activation by CD3-crosslinking or stimulation with Conconavalin A and Phytohemmaglutinin. Furthermore, we find that the ethanol-mediated enhancement of T cells to apoptosis involves increased activation of Caspase-3 and can be abrogated by treatment with a specific inhibitor of Caspase-3. CONCLUSIONS: Our data indicate that ethanol can sensitize CD4+ T cells to enhanced stimulation-induced Caspase-3 activation and to subsequent AICD. This is, perhaps, an important mechanism in alcohol-induced immunosuppression.