trichostatin-a and Pulmonary-Disease--Chronic-Obstructive

Diverse cellular functions including the regulation of inflammatory gene expression, DNA repair and cell proliferation are regulated by epigenetic changes. Transcriptional co-activators possess intrinsic histone acetyltransferase (HAT) activity, and histone acetylation plays a major role in inflammatory gene expression. Other marks such as histone methylation are also associated with gene induction and gene repression. Recent evidence implicates histone acetylation and methylation as being crucial for the development of tolerance in macrophages and CpG methylation for T regulatory cell development and function. The expression of the enzymes that lay down or remove these epigenetic marks have not been well studied in human airways disease, but reduced HDAC2 expression and activity is reported in lung macrophages, biopsies and blood cells from patients with COPD, severe asthma and smoking asthma. In vitro, inhibitors of histone deacetylases (HDAC) often lead to a further induction of inflammatory gene expression. This is not always the case, however, as HATs and HDACs also target non-histone proteins particularly transcription factors to alter their activity. Furthermore, trichostatin A, an HDAC inhibitor, can reduce inflammation in a murine model of allergic asthma. This effect of HDAC inhibitors may be due to their effects on cell death acting through acetylation of non-histone proteins. The role of epigenetic modifications in inflammatory gene expression and in the control of cell function in the airways is becoming clearer. Targeting specific enzymes involved in this process may lead to new therapeutic agents, in particular, in situations where current anti-inflammatory therapies are currently suboptimal.

Topics: Acetylation; Animals; Asthma; DNA Methylation; Enzyme Inhibitors; Epigenesis, Genetic; Gene Expression Regulation; Histone Acetyltransferases; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; Humans; Hydroxamic Acids; Immune Tolerance; Inflammation; Pulmonary Disease, Chronic Obstructive; Transcriptional Activation

During bacterial infections, pathogen-associated molecular patterns (PAMPs) induce cytokine/chemokine release in immunoactive cells. This increases corticosteroid-resistant airway inflammation in chronic obstructive pulmonary disease (COPD) and leads to exacerbations. Anti-inflammatory therapies other than corticosteroids are required and resveratrol is currently under discussion. Resveratrol is an activator of sirtuins, which are class III histone deacetylases (HDACs). We suggested that human airway smooth muscle cells (HASMCs) release COPD-associated cytokines/chemokines in response to lipoteichoic acid (LTA), a major PAMP of gram-positive bacteria and that resveratrol is superior to the corticosteroid dexamethasone in suppressing these cytokines/chemokines. Cultivated HASMCs of patients with COPD were pre-incubated with resveratrol or dexamethasone before stimulation with LTA. CCL2, GM-CSF, IL-6 and IL-8 were analysed in culture supernatants by enzyme-linked immunosorbent assay. Drug effects were investigated in the absence and presence of trichostatin A (TSA), an inhibitor of class I/II HDACs, and EX527, an inhibitor of the sirtuin SIRT1. LTA induced robust cytokine/chemokine release. Resveratrol was superior to dexamethasone in reducing CCL-2, IL-6 and IL-8 in LTA-exposed HASMCs of patients with COPD. Both drugs were equally effective in reducing GM-CSF. Resveratrol effects were partially reversed by EX527 but not by TSA. Dexamethasone effects were partially reversed by TSA but not by EX527. We conclude that HASMCs contribute to the increase in airway inflammation in COPD exacerbations caused by gram-positive bacterial infections. Our data suggest resveratrol as an alternative anti-inflammatory therapy in infection-induced COPD exacerbations. Resveratrol and corticosteroids suppress cytokine/chemokine expression through activation of SIRT1 or interaction with class I/II HDACs, respectively, in HASMCs.

Topics: Adrenal Cortex Hormones; Aged; Anti-Inflammatory Agents; Carbazoles; Chemokine CCL2; Cytokines; Dexamethasone; Female; Gram-Positive Bacteria; Granulocyte-Macrophage Colony-Stimulating Factor; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Interleukin-6; Interleukin-8; Lipopolysaccharides; Male; Middle Aged; Myocytes, Smooth Muscle; Pulmonary Disease, Chronic Obstructive; Respiratory System; Resveratrol; Sirtuin 1; Stilbenes; Teichoic Acids

The adenoviral protein E1A has been suggested to play a role in the pathophysiological development of chronic obstructive pulmonary disease (COPD) by inducing expression of inflammatory factors. It is well known that glucocorticoids are important inhibitors of inflammation. In the treatment of COPD corticosteroid therapy commonly has little or no anti-inflammatory effect. We hypothesized that the anti-inflammatory effect of glucocorticoids may be decreased or abolished by E1A expression, which aggravates the airway inflammation and results in the late stage of 'corticosteroid resistance' in COPD development. Corticosteroid therapy is a widely used method to treat respiratory inflammation. However, loss of anti-inflammatory effect is a common and serious complication during the therapy for COPD.. To test whether the E1A gene, which is 1 of the viral genes responsible for enhanced inflammatory responses, is involved in corticosteroid resistance during clinical therapy for COPD.. Rat alveolar epithelial cells were transfected with an E1A gene vector. Stably transfected cells were screened by PCR amplification of the E1A gene fragment. Transcription of the E1A gene was assayed by QT-RT-PCR. Protein expression was measured by immunohistochemistry and Western blot. E1A induced interleukin (IL)-6 secretion. mRNA levels were tested by ELISA and QT-RT-PCR. E1A-positive cells and E1A-negative cells were treated with lipopolysaccharide (LPS), physiological concentrations of hydrocortisone and trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC). The activity of HDAC was confirmed by colorimetric HDAC activity assay kit.. In all 4 E1A-expressing transfectants, expression of the E1A 243R protein was much higher than that of the 289R protein. LPS significantly increased IL-6 secretion in both E1A-positive and E1A-negative cells and no significant differences were found. Treatment with hydrocortisone at a physiological concentration clearly decreased LPS-induced IL-6 secretion, and this down-regulation effect could be abolished in the presence of TSA. LPS significantly decreased HDAC activity, which was completely abolished by application of hydrocortisone. Hydrocortisone alone had no effect on HDAC activity in cells without LPS stimulation. There were no differences in HDAC activity or IL-6 secretion under these treatments between E1A-positive and E1A-negative cells.. Our results indicated that a physiological concentration of glucocorticoid suppresses LPS-mediated IL-6 secretion, through the participation of HDAC. Expression of adenoviral E1A had no effect on HDAC activity and hydrocortisones induced an anti-inflammatory effect.

Topics: Adenovirus E1A Proteins; Animals; Cell Line; Glucocorticoids; Histone Deacetylases; Hydrocortisone; Hydroxamic Acids; Interleukin-6; Lipopolysaccharides; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive; Rats; Transfection

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease of the lungs with little or no response to glucocorticoids and a high level of oxidative stress. Histone deacetylase (HDAC) activity is reduced in cells of cigarette smokers, and low concentrations of theophylline can increase HDAC activity. We measured the effect of theophylline on HDAC activity and inflammatory gene expression in alveolar macrophages (AM) from patients with COPD. AM from normal smokers showed a decrease in HDAC activity compared with normal control subjects, and this was further reduced in COPD patients (51% decrease, P < 0.01). COPD AMs also showed increased basal release of IL-8 and TNF-alpha, which was poorly suppressed by dexamethasone. Theophylline induced a sixfold increase in HDAC activity in COPD AM lysates and significantly enhanced dexamethasone suppression of induced IL-8 release, an effect that was blocked by the HDAC inhibitor trichostatin A. Therefore, theophylline might restore steroid responsiveness in COPD patients.

Topics: Aged; Blotting, Western; Bronchodilator Agents; Enzyme-Linked Immunosorbent Assay; Female; Glutathione; Histone Deacetylases; Humans; Hydroxamic Acids; Immunohistochemistry; Inflammation; Interleukin-8; Lipopolysaccharides; Macrophages; Male; Middle Aged; Oxidative Stress; Pulmonary Disease, Chronic Obstructive; Smoking; Steroids; Theophylline; Tumor Necrosis Factor-alpha; U937 Cells