Expression Of Glucocorticoid Receptor Beta Research Articles

Increased lipopolysaccharide content is positively correlated with glucocorticoid receptor-beta expression in chronic rhinosinusitis with nasal polyps.

IntroductionChronic rhinosinusitis with nasal polyps (CRSwNP) is a common and frequently occurring disease of the upper respiratory tract. The nasal instillation of the Gram‐negative (G−) bacterial product lipopolysaccharide (LPS) can induce not only acute sinusitis but also the development of CRSwNP in animal models. Nevertheless, the expression and distribution of LPS in patients with CRSwNP have not been investigated. And the study was to investigate the expression of LPS and its relationship with glucocorticoid receptors (GRs) in CRSwNP.MethodsMultiple methods, including bacterial culture and immunohistochemistry, were used to detect and analyze nasal bacteria, plasma LPS content, and the levels of LPS and GR‐α/β, cluster of differentiation 68 (CD68), and myeloperoxidase (MPO) expression, as well as their relationship in CRSwNP.ResultsThe number of G− bacteria and Escherichia coli (E. coli) was not significantly different between CRSwNP subjects and the controls. However, the positive rate of LPS was much higher than that of E. coli in CRSwNP subjects and was significantly higher in noneosinophilic CRSwNP subjects than in eosinophilic CRSwNP subjects. Moreover, the LPS levels were positively correlated with GR‐β but not GR‐α expression in CRSwNP. Immunofluorescence assays showed that LPS was mainly detected in CD68+ macrophages and MPO+ neutrophils, in addition to histiocytes, in CRSwNP.ConclusionsPersistent LPS in CRSwNP can lead to unresolved mucosal inflammation, eventually leading to tissue remodeling and the development of CRSwNP. Our findings suggest that increased LPS content and possible resistance to glucocorticoids may be one of the important pathogenic mechanisms of G− bacteria in CRSwNP.

The effect of candesartan on chronic stress induced imbalance of glucose homeostasis

ObjectiveTo explore whether chronic stress induces imbalance of glucose homeostasis, and to investigate the possible involvement of the renin-angiotensin system (RAS). MethodsMale Sprague-Dawley rats were divided into four groups: control, chronic stress, chronic stress plus low dose candesartan (an angiotensin II receptor-1 blocker, ARB, 5 mg/kg/d, i.p.), chronic stress plus high dose candesartan (15 mg/kg/d, i.p.). Rats were received restraint stress for 14 days. Glucose transporter 2 (GLUT2) mRNA was quantified in liver by real-time polymerase chain reaction. The concentration of glucokinase (GK), glucose-6-phosphatase (G-6-P), glycogen synthase (GS), insulin receptor (ISR), glucocorticoid receptor (GR)-alpha and -beta in liver, hexokinase (HK), lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) in muscle, and serum insulin were measured by ELISA. Body weights, systolic blood pressure, heart rate and fasting blood glucose were monitored. Glucose tolerance test were performed after 14 days restraint stress. ResultsAfter 14 days restraint stress, systolic blood pressure, increase of plasma glucose concentration at 15 minutes were higher and the fasting plasma concentration of glucose was lower compared with control group (P < 0.05), which were reversed by high dose ARB treatment (P < 0.05). In addition, chronic stress decreased expression of GLUT2 and increased expression of GR beta in liver. High dose ARB treatment normalized GLUT2 and GR beta expressions in liver. ConclusionsOur present data indicate chronic stress induces the imbalance of glucose homeostasis and RAS contributes to the imbalance of glucose homeostasis induced by chronic stress.

Septic serum induces glucocorticoid resistance and modifies the expression of glucocorticoid isoforms receptors: a prospective cohort study and in vitro experimental assay

BackgroundA protective role for glucocorticoid therapy in animal models of sepsis was shown many decades ago. In human sepsis, there is new interest in glucocorticoid therapy at a physiological dose after reports of improved response to vasopressor drugs and decreased mortality in a selected group of patients. However, other reports have not confirmed these results. Cellular glucocorticoid resistance could explain a possible cause of that. To evaluate this hypothesis, we evaluated the expression of glucocorticoid receptor beta, the dominant negative isoform of glucocorticoid receptor, in peripheral mononuclear cells of septic patients and the effect of serum septic patients over glucocorticoid receptor expression and glucocorticoid sensitivity in immune cells culture.MethodsA prospective cohort study and an in vitro experimental study with matched controls were developed. Nine patients with septic shock and nine healthy controls were prospectively enrolled. Mononuclear cells and serum samples were obtained from the patients with sepsis on admission to the Intensive Care Unit and on the day of discharge from hospital, and from healthy volunteers matched by age and sex with the patients. Glucocorticoid receptor alpha and beta expression from patients and from immune cell lines cultured in the presence of serum from septic patients were studied by western blot. Glucocorticoid sensitivity was studied in control mononuclear cells cultured in the presence of serum from normal or septic patients. A statistical analysis was performed using a Mann-Whitney test for non-parametric data and analysis of variance for multiple comparison; P < 0.05 was considered significant.ResultsThe patients' glucocorticoid receptor beta expression was significantly higher on admission than on discharge, whereas the alpha receptor was not significantly different. In vitro, septic serum induced increased expression of both receptors in T and B cells in culture, with a greater effect on receptor beta than the control serum. Septic serum induced glucocorticoid resistance in control mononuclear cells.ConclusionThere is a transient increased expression of glucocorticoid receptor beta in mononuclear cells from septic patients. Serum from septic patients induces cell glucocorticoid resistance in vitro. Our findings support a possible cell glucocorticoid resistance in sepsis.

Importance of glucocorticoid receptors in upper and lower airways

Glucocorticoids (GCs) are the most common and effective drugs for treating inflammatory airway diseases, but some patients respond poorly to them. GC effects are mediated through the glucocorticoid receptor (GR). We present an update on the GR gene, the GR alpha and GR beta splicing variants, their translational and post-translational modifications, as well as their alterations in disease. GR alpha is ubiquitously expressed and is responsible for the induction and repression of target genes. GR beta acts as a dominant negative inhibitor of GR alpha-mediated transactivation and transrepression in certain cell types. The GR beta message is expressed at low levels in numerous tissues and its protein is only expressed in specific cell types. Increased GR beta expression has been reported in bronchial asthma, nasal polyposis and inflammatory bowel diseases (IBD), and after incubation of cells with certain proinflammatory stimuli. In addition to GR beta, other mechanisms explaining GC resistance include alterations in GR binding to ligand, nuclear translocation, and binding to GRE, and/or a defective cross-talk with transcription factors and cofactors.

Microbial superantigens induce glucocorticoid receptor beta and steroid resistance in a nasal explant model.

To study the role of superantigen (SAg) in inducing glucocorticoid (GC) receptor beta and steroid resistance in an explant model of nasal tissue. Nasal tissue was obtained from inferior turbinates of controls and ragweed (RW)-sensitive patients. Tissue samples were incubated with SAg of staphylococcal enterotoxin B. In addition, tissue samples from RW-sensitive patients were incubated with RW allergen in the presence and absence of both SAg and dexamethasone (DEX). The expression of GC receptor beta was assessed by immunocytochemistry. The expression of interleukin (IL)-2 and IL-4 mRNA was assessed by in situ hybridization. SAg induced an increase in the expression of GC receptor beta in atopic tissue and to a lesser extent in nonatopic tissue. The most significant induction of GC receptor beta was observed in response to SAg and RW in atopic tissue. Stimulation of atopic tissue with RW alone and SAg alone induced IL-4 and IL-2 mRNA, respectively. Incubation of atopic tissue with both SAg and RW induced both IL-2 and IL-4 mRNA. The increase in IL-4 mRNA expression was blunted by the addition of DEX to atopic tissue stimulated with RW alone but not to tissue stimulated by both RW and SAg. Our results demonstrate that SAgs induce steroid resistance in atopic nasal explant tissue by up-regulating the expression of GC receptor beta. Furthermore, we have shown that the up-regulation of GC receptor beta is a local event that is associated with the coexpression of IL-2 and IL-4 mRNA.

Steroid-Unresponsive Asthma

Although most patients with chronic asthma respond to corticosteroid therapy, a small subset of asthmatics are unresponsive to corticosteroids and demonstrate persistent airway obstruction and inflammation despite treatment with high doses of systemic glucocorticoids. There are at least two types of steroid-resistant asthma. Type I steroid-resistant (SR) asthma is cytokine induced and is associated with increased expression of glucocorticoid receptor beta, a less active glucocorticoid receptor isoform. Type II SR asthma is due to low numbers of glucocorticoid receptors. An important distinction between these two types of SR asthma is that the glucocorticoid receptor defect in Type I, but not Type II, SR asthma is reversible in culture and is sustained by incubation with combination interleukin (IL)-2 and IL-4. The treatment of these patients requires a systematic approach to rule out underlying conditions that lead to steroid resistance or treatment failure as well as the use of alternative strategies to inhibit airway inflammation.

Clinical pharmacology of inflammatory bowel disease therapies.

Knowledge about the clinical pharmacology of medical therapy of inflammatory bowel disease has incrementally advanced. Small studies with mesalamine have suggested that intestinal mucosal concentrations of mesalamine may predict clinical response to mesalamine therapy. Increased expression of glucocorticoid receptor beta and increased expression of the multidrug resistance drug pump P-glycoprotein 170 have been proposed as markers of drug resistance to glucocorticoids. A baseline determination of thiopurine methyltransferase phenotype or genotype may predict early leukopenia in patients treated with azathioprine or 6- mercaptopurine. Serial measurement of erythrocyte 6-thioguanine nucleotides may be useful in tailoring the dose of these medications. A loading dose of intravenous azathioprine does not accelerate the time to response in patients with steroid-treated Crohn's disease; however, standard azathioprine may work more quickly than previously reported. Methotrexate, 15 to 25 mg/wk, is effective for the treatment of Crohn's disease (active or in remission), and there is no significant difference in the erythrocyte concentrations of methotrexate polyglutamate in patients with inflammatory bowel disease receiving 15 mg, compared with 25 mg, subcutaneously on a weekly basis.

791 The relationship of glucocorticoid receptor-beta expression to Th1 and Th2 responses in the skin

791 The relationship of glucocorticoid receptor-beta expression to Th1 and Th2 responses in the skin

Inhibition of mineralocorticoid activity by the beta-isoform of the human glucocorticoid receptor.

Mineralocorticoids and glucocorticoids are important regulators of electrolyte homeostasis and arterial blood pressure. Their effects are mediated by the mineralocorticoid (MR) and the glucocorticoid receptor (GR), respectively. The present study was designed to determine how the two isoforms of the human GR, the "classic" GR alpha and the non-hormone-binding GR beta, interfere with the transcriptional effects of the hormone-activated human MR. COS-7 monkey kidney cells were transfected with different mineralocorticoid-responsive reporter plasmids and a vector expressing the human MR protein. Different amounts of either control, GR alpha, or GR beta plasmid were co-transfected, and luciferase activity was measured after stimulation with aldosterone and/or dexamethasone. MR-mediated stimulation of transcription was enhanced by co-transfection of the GR alpha expression vector. In contrast, MR-mediated stimulation of transcription was strongly inhibited by co-transfection of equal amounts of the GR beta expression vector. Reverse transcription-polymerase chain reaction (RT-PCR) showed expression of both GR isoforms as well as of MR in the human kidney. These data indicate that the two isoforms of the human GR exert opposite effects on mineralocorticoid activity. We conclude that the ratio between GR alpha and GR beta can define the sensitivity of mineralocorticoid target tissues to aldosterone. Imbalances of this ratio may participate in clinical syndromes of impaired or augmented mineralocorticoid sensitivity, such as certain cases of pseudohypoaldosteronism or, possibly, primary arterial hypertension.