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Glucocorticoids acting through their specific receptor can either enhance or repress gene transcription. Dexamethasone represses interleukin-1β-stimulated histone acetylation and granulocyte-macrophage colony-stimulating factor expression through a combination of direct inhibition of p65-associated histone acetyltransferase (HAT) activity and by recruiting histone deacetylase 2 (HDAC2) to the p65-HAT complex. Here we show that mifepristone, a glucocorticoid receptor partial agonist, has no ability to induce gene expression but represses interleukin-1β-stimulated histone acetylation and granulocyte-macrophage colony-stimulating factor release by 50% maximally. Mifepristone was able to inhibit p65-associated HAT activity to the same extent as dexamethasone but failed to inhibit the natural promoter to an equal extent due to an inability to recruit HDAC2 to the p65-associated HAT complex. These data suggest that the maximal repressive actions of glucocorticoids require recruitment of HDAC2 to a p65-HAT complex. These data also suggest that pharmacological manipulation of specific histone acetylation status is a potentially useful approach for the treatment of inflammatory diseases.
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Preamble Recent publications on the SYNTAX (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery) score have caught our attention and triggered a written reaction on the history and evolution of the SYNTAX score over the last decades. Among these publications, there is the editorial of Marie-Claude Morice, "Has the SYNTAX score become obsolete?"1. The most recent guidelines on revascularisation also question the ability of the SYNTAX II score to predict four-year all-cause mortality … even if the rate of mortality at four years in the EXCEL study was not yet available at the time ...
The cyclic nucleotides, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) play an important role in the regulation of airway smooth muscle tone and activation of inflammatory cells. Intracellular concentrations of these nucleotides are tightly regulated by phosphodiesterases (PDEs). Several families of PDEs are now recognized and, within each isoenzyme family, molecular cloning has revealed multiple members. PDE III and IV are important in the breakdown of cAMP; PDE III is involved in the regulation of airway smooth muscle tone, whereas PDE IV is more important in inflammatory cells, including mast cells, macrophages, eosinophils, T-lymphocytes and epithelial cells. PDE V is involved in the breakdown of cGMP in airway and vascular smooth muscle. Regulation of PDE expression in health and disease is now under investigation. Several selective PDE inhibitors have recently been developed, and experimental studies indicate that PDE IV inhibitors may be useful as anti-inflammatory treatments in asthma. Clinical trials in asthma are now in progress.
Inhaled glucocorticosteroids (GCS) decrease airway responsiveness (AR) in asthma by mechanisms that may involve suppressing airway inflammation and a reduction in the number of inflammatory cells in the airways. To investigate the functional response to a reduction in airway inflammatory cells in asthma, we studied the effects of inhaled budesonide on AR to three different bronchial challenges, adenosine 5′-monophosphate (AMP), which primarily activates mast cells; methacholine (MCh), a direct stimulus, and sodium metabisulfite (MBS), a neural stimulus. In a double-blind randomized crossover manner, with a washout period of 28 days, 12 subjects with mild asthma underwent inhalation challenge with doubling increments of MCh, MBS, and AMP before and after 14 days of treatment with budesonide 0.8 mg twice daily from a multidose dry-powder delivery system (Turbohaler) or matched placebo. Treatment with budesonide reduced AR to MCh and MBS to a similar degree, displacing the dose-response curve of each agonist to the right by 1.17 (95% confidence intervals, 0.34 to 2.00) and 1.06 (0.34 to 1.78) doubling dilutions, respectively, when compared with placebo (p < 0.01). Budesonide caused an additional and significantly greater reduction in AR to AMP, displacing the dose-response curve to the right by 2.92 (2.12 to 3.72) doubling dilutions when compared with placebo (p < 0.001) and to the other challenges (p < 0.01). We conclude that budesonide reduces AR to MCh and MBS by an action common to the effects of both direct and neural stimuli on airway smooth muscle contraction. The greater reduction in AR to AMP suggests that budesonide may have an additional action by reducing airway mast cell numbers and/or function.