Increased number of glucocorticoid receptor-β–expressing cells in the airways in fatal asthma (original) (raw)
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Glucocorticoid Receptors in Bronchial Epithelial Cells in Asthma
American Journal of Respiratory and Critical Care Medicine, 1998
The expression of the glucocorticoid receptor (GR) in untreated or in steroid-dependent asthmatic patients is poorly understood. We therefore studied GR mRNA and protein levels in bronchial biopsies obtained from seven untreated asthmatic patients, seven control volunteers, and seven patients with chronic bronchitis. We also studied in bronchial epithelial cells obtained by brushing from 13 untreated asthmatics, 18 steroid-dependent asthmatics, 11 control volunteers, and 12 patients with chronic bronchitis, GR and heat shock protein 90 kD (hsp90) mRNA as well as the immunoreactivity of GR, intercellular adhesion molecule (ICAM-1), and granulocyte macrophage-colony-stimulating factor (GM-CSF). GR mRNA and protein level was similar in all subject groups in both biopsies and bronchial epithelial cells. Hsp90 mRNA level was also similar in all subject groups. ICAM-1 expression was significantly increased in bronchial epithelial cells from untreated asthmatics, but ICAM-1 was not expressed in those from steroid-dependent asthmatic patients. GM-CSF expression was significantly increased in bronchial epithelial cells from untreated and steroid-dependent asthmatic patients. GR expression within the airways is unaltered by oral long-term steroid treatment in asthma, but the expression of some but not all specific markers for asthma is modified by oral steroid. Vachier I,
Is There a Role for Glucocorticoid Receptor Beta in Glucocorticoid-dependent Asthmatics?
American Journal of Respiratory and Critical Care Medicine, 2000
Glucocorticoids (GCs) are routinely used as anti-inflammatory drugs in the treatment of asthma. They act through binding to glucocorticoid receptor α (GRα), which represses numerous genes encoding pro-inflammatory mediators. A hormone binding deficient GR isoform named GRβ has been isolated in humans. When overexpressed by transfection, GRβ may function as a dominant negative modulator of GRα. However, to act as such, GRβ has to be more abundant than GRα, and conflicting data have been obtained concerning the relative levels of the two isoforms in cell lines and freshly isolated cells. Moreover, the dominant negative effect was not confirmed by independent laboratories. In GCresistant asthmatics, GRβ was expressed by an increased number of peripheral blood mononuclear cells (PBMCs), airway T cells, and cells found in skin biopsies of tuberculin responses. However, the relative amounts of GRα and GRβ in these cells were not determined. In GC-dependent asthmatics, PBMCs expressed GRα predominantly. No cells containing higher levels of GRβ than GRα have yet been reported in asthmatics. Even if the existence of such cells is demonstrated, the role of GRβ in asthma will remain a matter of controversy because functional studies have given discrepant data.
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N e w Y o r k S c i e n c e J o u r n a l 2 0 1 0 ; 3 ( 5 ) ABSTRACT Background: Glucocorticoids are the gold standard treatment of bronchial asthma. Although the majority of patients with asthma respond favorably to inhaled and systemic steroid therapy, a subset of asthmatics failed to demonstrate a satisfactory response even to systemic glucocorticoid therapy. GCR β (glucocorticoid receptor beta) is a hormone binding deficit isoform of GCR (glucocorticoid receptor) which has been isolated in humans and when over expressed, it may function as a dominant negative modulator of GCR. Aim of the work: This study was designed to determine the percentage of expression of GCRβ on PBMCs: (peripheral blood mononuclear cells )of asthmatic patients and to correlate it with the clinical severity and pulmonary functions. Subjects and Methods: 60 asthmatic patients (41 males, 19 females) and 20 healthy controls were enrolled in this study. Asthmatics were classified according to GINA guidelines (2002) into mild, moderate and severe asthma. They were subdivided into asthmatic on inhaled corticosteroid (ICS) (n=35) and those not on ICS (n=25). For all studied groups, spirometeric pulmonary functions and immunohisto-chemistry staining of PBMC S were performed to analyze percentage of expression of GCRβ on PBMCs. Results: It showed that the percentage of expression of GCRβ on PBMC S were statistically higher in all asthmatic patient groups compared to control, with higher % of expression in those not on ICS. Also a statistical significant higher % of expression of GCR β in severe asthmatics compared to both mild and moderate groups was detected. In conclusion: This study highlights the importance of glucocorticoid receptor beta isoform in pathogenesis of bronchial asthma and this may be directly linked to asthma severity and can affect the response to medications especially ICS. [New York Science Journal 2010;3(5):54-62]. (ISSN: 1554-0200).
Different Gene Expressions of Alpha and Beta Glucocorticoid Receptors in Asthmatics
Iranian journal of pharmaceutical research : IJPR, 2018
The response to glucocorticoids (GCs) therapy classifies severe refractory asthma (SRA) and mild asthma, so the glucocorticoid receptors (GCRs) gene expression may be involved in SRA pathogenesis. Thus, it is aimed to compare the expression levels of two GCR isoforms (GCRα and GCRβ) in SRA, mild asthmatics, and healthy controls. Total RNA was isolated from the peripheral blood mononuclear lymphocytes of 13 SRA patients, 14 mild asthma patients and 30 healthy volunteers. The expression levels of GCR isoforms were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). The expression level of GCR isoforms did not show any significant difference between the cases/control groups. However, the relative expression analysis between asthma/control, SRA/control and SRA/asthma groups was in the order of 0.933, 0.768 and 0.823 for GCRα and 0.697, 1.014 and 1.454 for GCRβ, respectively. Also, the expression fold change of GCRα/GCRβ in asthma, SRA and control groups was 786.8...
Proceedings of the National Academy of Sciences, 2005
Gene expression profiles were examined in freshly isolated peripheral blood mononuclear cells (PBMC) from two independent cohorts (training and test sets) of glucocorticoid (GC)-sensitive (n ؍ 64) and GC-resistant (n ؍ 42) asthma patients in search of genes that accurately predict responders and nonresponders to inhaled corticosteroids. A total of 11,812 genes were examined with high-density oligonucleotide microarrays in both resting PBMC (106 patients) and cells treated in vitro with IL-1 and TNF-␣ combined (88 patients), with or without GC. A total of 5,011 genes were expressed at significant levels in the PBMC, and 1,334 of those were notably up-regulated or down-regulated by IL-1͞TNF-␣ treatment. The expression changes of 923 genes were significantly reversed in GC responders in the presence of GC. The expression pattern of 15 of these 923 genes that most accurately separated GC responders (n ؍ 26) from the nonresponders (n ؍ 18) in the training set, based on the weighted voting algorithm, predicted the independent test set of equal size with 84% accuracy. The expression accuracy of these genes was confirmed by real-time-quantitative PCR, wherein 11 of the 15 genes predicted GC sensitivity at baseline with 84% accuracy, with one gene predicting at 81% in an independent cohort of 79 patients. We conclude that we have uncovered gene expression profiles in PBMC that predict clinical response to inhaled GC therapy with meaningful accuracy. Upon validation in an independent study, these results support the development of a diagnostic test to guide GC therapy in asthma patients.
Clinical & Experimental Allergy, 2010
Background Corticosteroid insensitivity in asthmatics is associated with an increased expression of glucocorticoid receptor-b (GR-b) in many cell types. T-helper type 17 (Th17) cytokine (IL-17A and F) expressions increase in mild and in difficult-to-treat asthma. We hypothesize that IL-17A and F cytokines alone or in combination, induce the expression of GR-b in bronchial epithelial cells. Objectives To confirm the expression of the GR-b and IL-17 cytokines in the airways of normal subjects and mild asthmatics and to examine the effect of cytokines IL-17A and F on the expression of GR-b in bronchial epithelial cells obtained from normal subjects and asthmatic patients. Methods The expression of IL-17A and F, GR-a and GR-b was analysed in bronchial biopsies from mild asthmatics and normal subjects by Q-RT-PCR. Immunohistochemistry for IL-17 and GR-b was performed in bronchial biopsies from normal and asthmatic subjects. The expression of IL-6 in response to IL-17A and F and dexamethasone was determined by Q-RT-PCR using primary airway epithelial cells from normal and asthmatic subjects. Results We detected significantly higher levels of IL-17A mRNA expression in the bronchial biopsies from mild asthmatics, compared with normal. GR-a expression was significantly lower in the biopsies from asthmatics compared with controls. The expression of IL-17F and GR-b in biopsies from asthmatics was not significantly different from that of controls. Using primary epithelial cells isolated from normal subjects and asthmatics, we found an increased expression of GR-b in response to IL-17A and F in the cells from asthmatics (P40.05). This effect was only partially significant in the normal cells. Dexamethasone significantly decreased the IL-17-induced IL-6 expression in cells from normal individuals but not in those from asthmatics (P40.05). Conclusion Evidence of an increased GR-b expression in epithelial cells following IL-17 stimulation suggests a possible role for Th17-associated cytokines in the mechanism of steroid hypo-responsiveness in asthmatic subjects.
Recent Topics in Steroid and Asthma: Beyond the 'Classic' Concept of Action
Glucocorticoid (GC)s exert anti-inflammatory effects via binding to the glucocorticoid receptor (GR) (NR3C1), targeted gene expression, and protein synthesis, which need hours before the onset of the action (transactivation). GCs also suppress inflammation by direct or indirect interaction with transcription factors, such as activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) (transrepression). Recently, the non-genomic actions of GCs were discovered on recognition of its rapid onset of action within seconds to minutes. GCs target many cells and tissues, including immune and inflammatory cells, airway epithelium, and airway smooth muscle (ASM). Of these, ASM is involved in altered airway contractility. A recent study demonstrated that GCs not only suppress inflammation but also exert direct effects on ASM gene expression which influence ASM function. GC resistance in the treatment of bronchial asthma remains a considerable clinical problem. Genes and cellular inflammatory phenotypes of glucocorticoid-resistant (GC-R) asthma have been revealed. Inflammation-associated protein kinase signaling and transcription factors affect GC actions through modulating GR function. Involvement of chromatin modifications have also been reported. Infection, reduced Vitamin D (Vit D), smoking, and obesity are preventable risk factors in GC-R asthma. Some of these recently available results are presented in this review.
Proliferation and activation of bronchial epithelial cells in corticosteroid-dependent asthma
Journal of Allergy and Clinical Immunology, 2001
Background: Structural and functional characteristics of bronchial epithelial cells in corticosteroid-dependent asthma are unknown. Objective: In bronchial biopsy specimens from 16 control, 9 untreated asthmatic, 9 inhaled corticosteroid-treated asthmatic, and 19 corticosteroid-dependent asthmatic subjects, we evaluated epithelium morphology and patterns of cell apoptosis, proliferation, and activation. Methods: We used the terminal deoxynucleotidyl-mediated dUTP nick end labeling (TUNEL) technique to study apoptosis. Immunohistochemistry was used to evaluate the expression of molecules related to apoptosis (such as Bcl-2 and P53), cell proliferation (PCNA), and cell activation (NFκB and CD40/CD40-L). Results: Epithelium thickness was higher in corticosteroiddependent asthmatic and control subjects than in inhaled corticosteroid-treated and untreated asthmatic subjects (P < .0001 and P < .0003). Very few TUNEL-positive epithelial cells were found in the 4 groups. Bcl-2 expression was higher in all groups of asthmatic subjects than in controls (P < .001). In corticosteroid-dependent asthmatic subjects, PCNA, NFκB, and CD40-L expression was higher than in inhaled corticosteroid-treated asthmatic (P < .001), untreated asthmatic (P < .001 and P < .04), and control (P < .01) subjects. CD40 expression was greater in corticosteroid-dependent asthmatic and untreated asthmatic subjects than in inhaled corticosteroidtreated asthmatic subjects (P < .0001 and P < .0006) and controls (P < .02 and P < .03). In corticosteroid-dependent asthma, PCNA expression was correlated with the epithelium thickness (P < .007). Conclusion: This study shows that in bronchial epithelial cells of corticosteroid-dependent asthma, markers of cell survival and proliferation are coexpressed with markers of cell activation, suggesting that in this disease epithelium repair is associated with a persistent activation state of epithelial cells. (J Allergy Clin Immunol 2001;108:738-46.)
Journal of Allergy and Clinical Immunology, 1996
Background: Glucocorticoids are important medications used to control the airway inflammation associated with asthma. Synthetic glucocorticoids vary in their binding affinity for the glucocorticoid receptor (GCR). Methods: We compared hydrocortisone, beclomethasone dipropionate, triamcinolone acetonide, flunisolide, and budesonide with regard to their capacity to inhibit phytohemagglutinin-induced peripheral blood mononuclear cell proliferation from six patients with steroid-sensitive asthma and seven patients with steroid-resistant asthma. Peripheral blood mononuclear cell GCR binding afinities for dexamethasone and budesonide were also determined for both patient groups by using a radioligand binding assay and Scatchard analysis. Results: Dose-dependent inhibition was demonstrated for all glucocorticoids in both patient groups, with the steroid-resistant group requiring approximately 2 log-foM more glucocorticoids for an equivalent degree of inhibition. The mean concentrations necessary to cause 50% inhibition of lymphocyte proliferation (ICsos) for the steroid-sensitive group ranged from 2 • 10-1~ mol/L for budesonide to 7 x 10 s mol/L for hydrocortisone, whereas the mean ICsos for the steroidresistant group ranged from approximately 2 • 10 -s mol/L for budesonide to greater than 10 6 mol/L for hydrocortisone. In addition, a significant correlation was noted between the degree of inhibition of lymphocyte proliferation (ICso) and the binding affinity of dexamethasone to the GCR. Patients with steroid-resistant asthma have been shown to have a reduced GCR binding affinity. The GCR binding affinity for budesonide was significantly higher in both groups (i.e., lower dissociation constant) than that obtained for dexamethasone. Conclusion: These data suggest that glucocorticoids such as budesonide, by virtue of their high GCR binding affinities and greater ability to suppress lymphocyte proliferation, may therefore be beneficial in the management of difficult-to-control asthma. (J Allergy Clin Immunol 1996;98.'1073-9.)