Expression of the glucocorticoid receptor alpha and beta isoforms in human nasal mucosa and polyp epithelial cells

Dexamethasone-stimulated glucocorticoid receptor signaling positively regulates the endoplasmic reticulum-associated degradation (ERAD) mechanism in hepatocellular carcinoma cells

Hepatocellular carcinoma is one of the most common types of primary liver cancer in adults and also it is the third leading cause of cancer-related deaths worldwide. Although there are various treatment options such as surgery, radiation, targeted drug therapy, immunotherapy and chemotherapy, most hepatocellular carcinomas are highly resistant to systemic treatments. Today, the molecular pathogenesis of hepatocellular carcinoma remains largely obscure. Therefore, there is a need for detailed research for the characterization of molecular signaling networks related to the development of hepatocellular carcinoma. Recent studies have attention to the hormonal regulation of hepatocellular carcinoma cells mediated by systemic hormones such as glucocorticoids. However, glucocorticoid-mediated regulation of endoplasmic reticulum-associated degradation (ERAD) and unfolded protein response (UPR), which are known to be important survival mechanisms for cancer cells remains unknown in hepatocellular carcinoma. In the present study, we showed that dexamethasone-induced glucocorticoid receptor signaling mediated advanced regulation of ERAD and UPR signaling in hepatocellular carcinoma cells. Glucocorticoid signaling positively regulates mRNA and protein levels of ERAD components and also protein kinase RNA-like ER Kinase (PERK) and inositol-requiring enzyme 1⍺ (IRE1⍺) branches of UPR signaling are accompanied the glucocorticoid signaling. In addition, putative glucocorticoid response elements (GREs) were determined in the promoter regions of ERAD members in in-silico analyses. Additionally, silencing of ERAD components significantly reduced the tumorigenic features of hepatocellular carcinoma cells, including cell proliferation, metastasis, invasion and 3D tumor formation. Collectively, these results reveal a novel pattern of regulation of ERAD components by glucocorticoid-mediated in human hepatocellular carcinoma cells.

Prenatal dexamethasone exposure programs the decreased testosterone synthesis in offspring rats by low level of endogenous glucocorticoids

Prenatal dexamethasone exposure (PDE) can decrease maternal endogenous glucocorticoid level and induce testicular dysplasia in male offspring rats. In this study we investigated low level endogenous glucocorticoid-mediated testicular dysplasia in PDE offspring and elucidated the intrauterine epigenetic programming mechanisms. Pregnant rats were injected with dexamethasone (0.2 mg·kg^-1·d^-1, sc) on gestational day (GD) 9-20. The offspring rat blood and testis were collected after euthanasia on GD20, postnatal week (PW) 12 or PW28. We showed that PDE induced abnormal morphology of testis and significantly decreased the expression of testosterone synthesis-related genes as well as testosterone production before and after birth. Meanwhile, serum corticosterone, the expression and histone 3 lysine 14 acetylation (H3K14ac) of testicular insulin-like growth factor 1 (IGF1) were significantly decreased. After the pregnant rats were subjected to chronic stress for 2 weeks (PW10-12), serum corticosterone level was increased in the adult PDE offspring, and the above-mentioned other indicators were also improved. Cultured Leydig cells (TM3) were treated with corticosterone (62.5-500 nM) in vitro. We showed that corticosterone concentration-dependently inhibited glucocorticoid receptor α (GRα) and miR-124-3p expression, increased histone deacetylase 5 (HDAC5) expression, and decreased IGF1 H3K14ac level and the expression of IGF1/steroidogenic acute regulatory protein (StAR), suggesting that corticosterone at lower than physiological level (<500 nM) inhibited testosterone synthesis by reducing H3K14ac and the expression level of IGF1 through GRα/miR-124-3p/HDAC5 pathway. In conclusion, PDE can cause persistent inhibition of testosterone synthesis before and after birth in the offspring rats by low level of endogenous glucocorticoids.

Immune cell infiltration and related core genes expression characteristics in eosinophilic and non-eosinophilic chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) refers to chronic inflammation of the sinonasal mucosa. It can either be eosinophilic (ECRSwNP) or non-eosinophilic (non-ECRSwNP). However, immune cell infiltration in the microenvironment and pathogenesis of ECRSwNP and non-ECRSwNP are still unclear. The aim of the present study was to assess the immune cell infiltration and molecular mechanisms of ECRSwNP and non-ECRSwNP. In the present study, 22 immune cell types in ECRSwNP and non-ECRSwNP were investigated by CIBERSORT based on transcriptome data. The core gene related pathophysiology of CRSwNP was analyzed using Weighted Gene Correlation Network Analysis according to the phenotype of the infiltrated eosinophils and nasal polyps (NP). A total of four types of immune cells (mast cells, activated dendritic cells, M2 macrophages and activated natural killer cells) were demonstrated to have a direct and indirect correlation with eosinophilic infiltration in ECRSwNP. M1 macrophages and activated CD4⁺ memory T cells were correlated with major immune cell types in non-ECRSwNP. NP could affect the expression of ‘olfactory receptor activity’ and ‘channel activity’ genes to impair the olfactory signaling pathway and neuroactive ligand receptor pathway. ‘Cell adhesion molecule binding’, ‘cytokine receptor binding’ and ‘glucocorticoid receptor binding’ were significantly enriched in ECRSwNP, whereas epithelial cell injury, autophagy and the mTOR pathway (hsa04140 and hsa04150) may serve an important role in the pathogenesis of non-ECRSwNP. There were significantly different immune cell infiltration and related core genes expression characteristics between ECRSwNP and non-ECRSwNP. The results of the present study provide an improved basis for elucidation of the mechanism and treatment of CRSwNP.

Longitudinal evaluation of glucocorticoid receptor alpha/beta expression and signalling, adrenocortical function and cytokines in critically ill steroid-free patients

PURPOSE

Glucocorticoid actions are mediated by the glucocorticoid receptor (GCR) whose dysfunction leads to glucocorticoid tissue resistance. Our objective was to evaluate GCR-α and GCR-β expression and key steps in the GCR signalling cascade in critical illness.

METHODS

Expression of GCR and major GCR-target genes, cortisol, adrenocorticotropin (ACTH) and cytokines was measured in 42 patients on ICU admission and on days 4, 8, and 13. Twenty-five age- and sex-matched subjects were used as controls.

RESULTS

Acutely, mRNA expression of GCR-α was 10-fold and of GCR-β 3-fold the expression of controls, while during the sub-acute phase expression of both isoforms was lower compared to controls. Expression of FKBP5 and GILZ decreased significantly. Cortisol levels remained elevated and ACTH increased during the 13-day period.

CONCLUSIONS

GCR expression and hypothalamic-pituitary-adrenal axis function undergo a biphasic response during critical illness. The dissociation between low GCR expression and high cortisol implies an abnormal stress response.

Benefits and harm of systemic steroids for short- and long-term use in rhinitis and rhinosinusitis: an EAACI position paper

Because of the inflammatory mechanisms of most chronic upper airway diseases such as rhinitis and chronic rhinosinusitis, systemic steroids have been used for their treatment for decades. However, it has been very well documented that—potentially severe—side-effects can occur with the accumulation of systemic steroid courses over the years. A consensus document summarizing the benefits of systemic steroids for each upper airway disease type, as well as highlighting the potential harms of this treatment is currently lacking. Therefore, a panel of international experts in the field of Rhinology reviewed the available literature with the aim of providing recommendations for the use of systemic steroids in treating upper airway disease.

Lack of additive benefit of oral steroids on short-term postoperative outcomes in nasal polyposis

OBJECTIVES

There is a lack of evidence concerning the efficacy of oral corticosteroids (OCS) as a postoperative treatment for patients with chronic rhinosinusitis with nasal polyps (CRSwNP). The objective of our study was to determine the short-term additive benefit of postoperative OCS in CRSwNP patients.

METHODS

We prospectively randomized CRSwNP patients who were treated by endoscopic sinus surgery. All patients were resistant to maximum medical treatment according to European position paper on rhinosinusitis and nasal polyps 2012 guidelines. Treatment group received postoperative OCS in descending doses plus nasal douching over a period of 4 weeks, whereas the control group received only nasal douching. The efficacy of OCS was determined by a total 5 item symptoms score (T5SS), polyp size score, Barcelona Smell Test 24 and Medical Outcome Study Short Form-36 questionnaire for quality of life (QoL).

RESULTS

Of the 70 enrolled patients, 35 were in the treatment group and 35 in the control group. After 4 weeks of follow-up, patients from both groups improved in T5SS, QoL, endoscopic findings (except for crusts that increased in both) and sense of smell, without significant differences between OCS and control groups.

CONCLUSION

Postoperative OCS as an add-on treatment for CRSwNP patients does not improve sinonasal and QoL outcomes; thus, they should not be routinely recommended.

LEVEL OF EVIDENCE

Ib Laryngoscope, 2019.

Topical Steroids in Rhinosinusitis and Intraoperative Bleeding: More Harm Than Good?

The aim of this study was to assess whether the chronic preoperative administration of intranasal corticosteroids (INCs) in chronic rhinosinusitis with/without nasal polyposis (CRSwNP/CRSsNP, respectively) could significantly influence bleeding during functional endoscopic sinus surgery (FESS). We prospectively enrolled 109 patients (56 CRSwNP and 53 CRSsNP) candidate for FESS who underwent clinical evaluation and anamnestic data collection. They were allocated to 2 groups depending on whether or not they were chronic INC users, as declared at their first medical evaluation: chronic "INC users" represented the treated group, while "INC nonusers" formed the control group. Lund-Mackay and American Society of Anesthesiology (ASA) scores, blood loss expressed both in milliliters and using the Boezaart scale, operation time in minutes, pre- and postoperative 22-item Sino Nasal Outcome Scores (SNOT-22) were collected. Each sample underwent histopathological evaluation. The results showed that anamnestic information, Lund-Mackay, and SNOT-22 scores were similar between the 2 groups (P > .05). The average blood loss expressed in milliliters and operative time were slightly, but not significantly, higher in the INC user group, while the Boezaart scores proved significantly higher in the INC users (P = .038). No differences emerged between CRSwNP and CRSsNP within each group in terms of bleeding. The pathologist described common features in the majority (78%) of INC group samples: ectatic venules embedded in a fibrous stroma and hypertrophy of the arterial muscular layer. In our experience, despite the presence of NP, chronic preoperative administration of INCs was associated with increased intraoperative bleeding according the Boezaart scale although objective recordings of blood loss were not statistically different between the INC users and nonusers.

Decreased glucocorticoid receptor expression during critical illness

INTRODUCTION

In critically ill patients, the hypothalamic-pituitary-adrenal axis is activated, resulting in increased serum cortisol concentrations. However, in some patients, especially those with sepsis, cortisol levels are relatively low for the degree of illness severity. Therefore, in the present project, we aim to characterize the time course of glucocorticoid receptor (GCR) alpha and beta expression in peripheral polymorphonuclear cells of critically ill septic or nonseptic patients using real-time PCR.

DESIGN

A prospective observational study conducted on 32 critically ill adults not receiving steroids, in a university-affiliated, multidisciplinary intensive care unit (ICU). Blood samples were collected for measurement of glucocorticoid receptor expression within 24-48 hours of admission to the ICU and at days 4, 8 and 13 after admission, reflecting the acute and chronic phase of the illness.

RESULTS

During ICU stay, patients expressed over time reduced levels of both GCR-α and GCR-β mRNA. More specifically, GCR-α mRNA expression was decreased fourfold 4 days after admission (P < 0.0001) and remained low up to 2 weeks after admission (P < 0.001). On the other hand, GCR-β mRNA levels remained stable shortly after admission, but approx. one week after admission, its levels decreased threefold (P < 0.01) and remained reduced up to 2 weeks after admission (P < 0.001).

DISCUSSION

Our results suggest that critically ill patients have highly variable expression of alpha and beta GCR, and moreover, the levels of both receptors decrease during ICU stay. Taken together, these might explain the differential responsiveness of patients to exogenous steroid administration or to endogenous cortisol secretion.

Risks and management of long-term corticosteroid use in chronic rhinosinusitis

PURPOSE OF REVIEW

The purpose of this review is to provide an update on the use and risks of long-term corticosteroids in the management of chronic rhinosinusitis (CRS).

RECENT FINDINGS

Long-term use of systemic corticosteroids is not indicated in the management of CRS due to the associated side effects and potential complications. Therefore, recent research has focused on the safety and efficacy of topical corticosteroid, particularly second-generation corticosteroids, and their modes of administration. Second-generation corticosteroids are more potent and have less systemic bioavailability than their first-generation counterparts. However, caution must be taken with concomitant use of more than two types of corticosteroids (topical, systemic, inhaled etc.) and also with their dosage and frequency of administration to avoid adrenal suppression, growth suppression in children, elevated intraocular pressure or epistaxis. Research is ongoing into therapies that may reduce corticosteroid resistance which has been demonstrated in some nasal polyps.

SUMMARY

Corticosteroids play an essential role in the management of CRS; however, use must be tailored to the patient-specific disease and requires ongoing review and regular reevaluation by their physician.

The effects of hydrocortisone on tight junction genes in an in vitro model of the human fallopian epithelial cells

The tight junction between epithelial cells helps making connections in the fallopian tube and contributes to successful fertilization. Breaking the tight junction complex induces various diseases such as the EP. Previous studies have shown that glucocorticoids are effective in repairing and maintaining intercellular tight junctions in epithelial cells of the fallopian tube, although their mechanism is still unknown. This research is a genomic study of hydrocortisone's effect on epithelial cells of the fallopian tube. Using the human fallopian tube, epithelial cell line (OE-E6/E7) was cultured in four concentrations of hydrocortisone (0 nM, 50 nM, 100 nM and 200 nM) for three durations (24 h, 48 h and 72 h). Glucocorticoids are effective on the expression of Zona occluding-1(ZO-1), Claudin 4, Claudin3, Desmoglein and E-cadherin genes involved in the tight junctions of the fallopian tube. The expression of all genes was up-regulated in the concentrations of 100 nM after 48 h treatment, as compared with the control (0 nM). However, their expression was down-regulated significantly after 72 h treatment (P < 0.05). The present study showed that treatment of epithelial cells of the fallopian tube with glucocorticoid increased the expression of genes involved in tight junctions, including claudin-3, claudin-4, E-cadherin, zona occludin-1 and Desmoglein-1. The obtained data suggests that a new mechanism is developed for glucocorticoid induction of tight junctions by increasing the expression of claudin-3, claudin-4, E-cadherin, zona occludin-1 and Desmoglein-1 genes.

Glucocorticoid receptor isoform expression in peripheral blood mononuclear leukocytes of patients with chronic rhinosinusitis

BACKGROUND

In several inflammatory disorders, altered peripheral blood mononuclear leukocyte (PBML) glucocorticoid (GC) receptor isoform expression has been associated with GC resistance and disease severity. However, it is unclear if PBML GC receptor isoforms are expressed differentially and are associated with worsened disease severity in chronic rhinosinusitis (CRS).

METHODS

PBMLs were isolated from control (n = 8), CRS without nasal polyps (CRSsNP) (n = 8), atopic CRS with nasal polyps (CRSwNP) (n = 8), non-atopic CRSwNP (n = 8), and allergic fungal rhinosinusitis (AFRS) (n = 8) patients. Demographics, atopic status, asthmatic status, 22-item Sino-Nasal Outcome Test (SNOT-22) scores, Lund-Kennedy nasal endoscopy scores, Lund-Mackay sinus computed tomography (CT) scores, Kennedy Osteitis scores, and GC utilization 6 months postoperatively were collected. Intracellular immunostaining was then performed for functional GC receptor α (GCRα) and nonfunctional GC receptor β (GCRβ), followed by flow cytometry analysis of geometric mean fluorescent intensity (MFI) and the percentage of cells expressing each GC receptor isoform.

RESULTS

Compared to controls, each CRS subtype had decreased PBML GCRα and GCRα:GCRβ MFI expression, but no difference in GCRβ expression. Decreasing PBML GCRα in AFRS was associated with increasing Lund-Mackay sinus CT scores (r = -0.880, p =0.004). No significant associations were found between GC receptor isoform expression and other clinical measures.

CONCLUSION

CRS patients have reduced functional PBML GCRα expression and decreased GCRα:GCRβ compared to controls. Reductions in GCRα in AFRS are associated with worsening Lund-Mackay sinus CT scores. The clinical implications of decreased functional GC receptor expression merits further investigation.

Contemporary Use of Corticosteroids in Rhinology

PURPOSE OF REVIEW

Exogenously administered corticosteroids are widely used today in the field of rhinology. Allergic rhinitis (AR), non-allergic rhinitis (NAR), acute rhinosinusitis (ARS), chronic rhinosinusitis with (CRSwNP) and without (CRSsNP) nasal polyps, and autoimmune disorders with nasal manifestations are common diseases treated effectively with intranasal and oral glucocorticoids. We focus on physiological pathways, therapeutic benefits, indications, contra-indications, and side effects of glucocorticoid utilization in the treatment of rhinologic disorders such as AR, NAR, ARS, CRSsNP, and CRSwNP.

RECENT FINDINGS

Second-generation intranasal steroid (INS) agents have pharmacokinetic characteristics that minimize their systemic bioavailability, resulting in minimum risk for systemic adverse events. Several studies have demonstrated the symptomatic efficacy of both intranasal and oral corticosteroids in ARS. Moreover, intranasal and systemic steroid administration has been repeatedly proven beneficial in the conservative and perioperative management of CRSwNP. For patients with AR, there is no need for oral steroids, with the exception of severe cases, as there is lack of superiority to INS. SCUAD patients challenge currently available treatment schemes, underlining the importance of research in the field. Corticosteroids' effectiveness in the treatment of various rhinologic disorders is indisputable. However, their characteristics, and potential side effects, make a clear consensus for utilization difficult.

Pathogenesis of eosinophilic chronic rhinosinusitis

Eosinophilic chronic rhinosinusitis (ECRS) is considered a refractory and intractable disease. Patients with ECRS present with thick mucus production, long-term nasal congestion, loss of sense of smell, and intermittent acute exacerbations secondary to bacterial infections. Despite medical and surgical interventions, there is a high rate of recurrence with significant impairment to quality of life. The recent increasing prevalence of ECRS in south Asian countries and the strong tendency of ECRS to reoccur after surgery should be considered. The majority of cases need repeat surgery, and histological examinations of these cases show eosinophilic-dominant inflammation. The degradation and accumulation of eosinophils, release of cytokines, and mucus secretion have important roles in the pathogenesis of ECRS. ECRS differs from non-ECRS, in which eosinophils are not involved in the pathogenesis of the disease, and also in terms of many clinical characteristics, blood examination and nasal polyp histological findings, clinical features of the disease after surgery, efficacy of medications, and computed tomography findings. This review describes the clinical course, diagnosis, and treatment of ECRS as well as its pathophysiology and the role of eosinophils, mucus, cytokines, and other mediators in the pathogenesis of ECRS.

Mechanisms of Glucocorticoid Action in Chronic Rhinosinusitis

The innate immune system and its complex interplay with the adaptive immune system are increasingly being recognized as important factors in the pathogenesis of chronic rhinosinusitis (CRS). Adaptive immune components, including resident and inflammatory cells, and their associated mediators, have been the subject of most research in CRS. For this reason, theories of CRS pathogenesis have involved the concept that inflammation, rather than infection, is the dominant etiologic factor in CRS. Therefore, glucocorticoids are increasingly used to treat CRS. This review will outline our current knowledge of action mode of glucocorticoids in CRS.

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

Background

A 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.

Methods

A 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.

Results

The 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.

Conclusion

There 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.

Brazilian Academy of Rhinology position paper on topical intranasal therapy

This documents aims at educating those who treat sinonasal diseases - both general practitioners and specialists - about topical nasal treatments. By means of scientific evidence reviews, the Brazilian Academy of Rhinology provides its practical and updated guidelines on the most utilized topical nasal medication, except for the drugs that have topical antibiotics in their formulas.

Expression of the cysteinyl leukotriene 1 receptor and glucocorticoid receptor-β in nasal polyps

The objective of this study was to analyze the expression of cysteinyl leukotriene 1 (CysLT1) receptor and glucocorticoid receptors (GRs) in nasal polyps, and to evaluate the relationship between the expression of CysLT1 receptors and that of GRs. Nasal polyps were taken from 32 patients of chronic rhinosinusitis with nasal polyposis. Samples of middle turbinate from seven healthy subjects were used as controls. Specimens were immunohistochemically stained for CysLT1 receptor, GR-α and GR-β receptor, and were quantified in the unit area of the tissues. Numbers of CysLT1 receptor-positive cells were much increased in nasal polyps than in middle turbinate (281 ± 67 vs. 157 ± 85 cells/mm(2), P = .01). There was no significant difference in the numbers of GR-α positive cells between nasal polyps and normal turbinate mucosa. GR-β positive cells were increased in nasal polyps as compared to normal turbinate mucosa (36 ± 8 vs. 19 ± 7 cells/mm(2), P = .03). A significant relationship was found between the expression of CysLT1 receptor and GR-β in nasal polyps (R = .525, P = .04), whereas there was no significant relationship between the expression of CysLT1 receptor and GR-α in nasal polyps. Our study shows that CysLT1 receptor expression predominates on GR-β over-expressed polyps. This may suggest the additional effect of CysLT1 receptor antagonist for the treatment of nasal polyposis resistant to steroid alone.

Pathological mechanisms and clinical features of eosinophilic chronic rhinosinusitis in the Japanese population

The overall pathological view of paranasal sinus inflammation in the Japanese population has profoundly changed in recent years. Eosinophilic chronic rhinosinusitis (ECRS) is a clinical entity of intractable chronic sinus inflammation accompanied by numerous infiltrations of activated eosinophils in the paranasal sinus mucosa and/or nasal polyps. Several pathologic processes are considered to act in concert to promote the accumulation of eosinophils in ECRS. They include infiltration of progenitor cells, increase in local IL-3, IL-5, IL-13, GM-CSF and eotaxin production, and upregulation of adhesion molecules. The role of nasal allergen sensitization and innate immunity responses in the sinus mucosa has also been proposed in the development of ECRS. Various pathogens including TLRs ligands may trigger an abnormal immune response at the mucosal surface. The objectives of ECRS management should focus directly on inhibition of local eosinophil infiltration. Surgical procedures include widely opening the bony wall septum of every affected sinus and mechanical removal of diseased mucosal lesion. The use of local and/or systemic steroids, leukotriene receptor antagonists, and Th2 cytokine antagonists is recommended. Local administration of steroids is a potent treatment strategy for preventing relapse of nasal polyposis and is considered to be the first-line treatment for ECRS patients.

The role of local steroid injection for nasal polyposis

Sinonasal polyps affect a small but significant percentage of patients with chronic sinusitis. Treatments vary and range from oral and topical medical treatments to surgical removal. Corticosteroids typically have been regarded as the gold standard medical treatment for sinonasal polyps. Delivery of steroids is traditionally via oral or topical means. Over the years, otolaryngologists have also found that intrapolyp injection of corticosteroids is an effective means to treat some patients with sinonasal polyps. This article reviews the prevalence, pathophysiology, and medical treatment options for sinonasal polyps. Focused attention is paid to treatment with steroid injections, including a review of its associated risks and benefits.

Glucocorticoid receptor-beta and receptor-gamma exert dominant negative effect on gene repression but not on gene induction

Glucocorticoid has diverse biological effects through induction or repression of its target genes via glucocorticoid receptor (GR). In addition to the wild-type GR (GR-alpha), a variety of GR variants has been reported, and these are thought to modify glucocorticoid action. Among others, GR-beta is reported be responsible for the glucocorticoid resistance frequently observed in steroid-resistant nephrotic syndrome, rheumatoid arthritis, and hematologic tumors, although the precise molecular mechanism remains unclear. In this study, we examined the function of GR-beta and some GR variants (GR-gamma and GR-Delta313-338) using GR-deficient BE(2)C and T84 cells in vitro. We found that GR-beta, when expressed alone, completely lost the capacity of both trans-activation and trans-repression on GR target genes. Interestingly, however, GR-beta showed a dominant-negative effect on GR-alpha only for its trans-repressive effects on cAMP-mediated and cAMP response element-dependent genes. Furthermore, both GR-beta and GR-gamma had dominant-negative effects on GR-alpha selectively for its trans-repressive effects on nuclear factor-kappaB-mediated and inflammation-related genes. These results suggest that 1) the GR-beta variant by itself has no receptor function, but 2) GR-beta and GR-gamma have properties to exert dominant-negative effects on the GR-alpha-mediated trans-repression, which may be responsible for the steroid resistance frequently observed in chronic inflammatory diseases under glucocorticoid therapy.

Expression and distribution of glucocorticoid receptor isoforms in eosinophilic chronic rhinosinusitis

OBJECTIVE

Patients with eosinophilic chronic rhinosinusitis (ECRS) show a high percentage of eosinophilic infiltration in the paranasal sinus mucosa. It is well documented that topical steroids have a beneficial effect in ECRS with nasal polyposis. We investigated mucosal distribution and cellular localization of glucocorticoid receptor (GR) isoform expression in human paranasal sinuses in relation to the clinical characteristics of eosinophilic chronic rhinosinusitis (ECRS) patients.

METHODS

Mucosal specimens were obtained from 20 sinusitis patients by endoscopic sinus surgery (ESS). Quantitative fluorescence immunohistochemical analysis was employed to examine the degree of glucocorticoid receptor (GR) isoform expression in sinus mucosa specimens. An RT-PCR procedure was performed to determine the relative quantities of mRNA for the human GRalpha and GRbeta genes.

RESULTS

Patients in the ECRS group showed significant increases in peripheral blood eosinophils as compared to the non-ECRS group (16.98% vs. 2.31%). Positive immunoreactivity of GRbeta expression was predominantly found to be positive in inflammatory cells. The absolute number of GRbeta-positive cells in the ECRS group was increased in comparison with that in the non-ECRS group. The difference was statistically significant both in the maxillary (179.7 cells/mm(2) vs. 82.5 cells/mm(2)) and ethmoid sinus (302.0 cells/mm(2) vs. 61.5 cells/mm(2)) mucosa. The GRbeta/GRalpha cell ratio in the ECRS group was elevated when compared with that in the non-ECRS group both in the maxillary and the ethmoid sinus mucosa, with the latter difference being significant.

CONCLUSIONS

The presence of high peripheral eosinophilia indicates a high likelihood of ECRS disease. Our results support the association of GRbeta expression with ECRS. The expression of GRbeta immunoreactivity, an endogenous inhibitor of steroid action previously associated with steroid insensitivity, may be one of major contributing factors in ECRS.

Corticosteroid treatment in chronic rhinosinusitis: the possibilities and the limits

Chronic rhinosinusitis, including nasal polyps, is an inflammatory disease of the nose and sinuses. The medical treatment, mainly topical intranasal and oral corticosteroids, constitutes its first line of therapy. Long-term treatment with corticosteroid nasal spray reduces inflammation and nasal polyp size, and improves nasal symptoms such as nasal blockage, rhinorrea, and the loss of smell. Corticosteroid intranasal drops may be used when intranasal spray fails to demonstrate efficacy. Short courses of oral steroids are recommended in severe chronic rhinosinusitis with nasal polyps or when a rapid symptomatic improvement is needed. Endoscopic sinus surgery is only recommended when the medical treatment fails. Intranasal corticosteroids should be continued postoperatively. When using intranasal corticosteroids, care should be taken in selected populations such as children, pregnant women, and elderly patients; especially in those patients with comorbid conditions such as asthma, in which the overall steroid intake can be high due to the administration of both intranasal and inhaled corticosteroids.

Human glucocorticoid receptor isoform beta: recent understanding of its potential implications in physiology and pathophysiology

The human glucocorticoid receptor (GR) gene expresses two splicing isoforms alpha and beta through alternative use of specific exons 9alpha and 9beta. In contrast to the classic receptor GRalpha, which mediates most of the known actions of glucocorticoids, the functions of GRbeta have been largely unexplored. Owing to newly developed methods, for example microarrays and the jellyfish fluorescence proteins, we and others have recently revealed novel functions of GRbeta. Indeed, this enigmatic GR isoform influences positively and negatively the transcriptional activity of large subsets of genes, most of which are not responsive to glucocorticoids, in addition to its well-known dominant negative effect against GRalpha-mediated transcriptional activity. A recent report suggested that the "ligand-binding domain" of GRbeta is active, forming a functional ligand-binding pocket associated with the synthetic compound RU 486. In this review, we discuss the functions of GRbeta, its mechanisms of action, and its pathologic implications.

Glucocorticoid receptor immunoreactivity of eosinophils in nasal polyps

CONCLUSION

The higher level of glucocorticoid receptor (GR) expression in cases of chronic sinusitis with bronchial asthma or allergic rhinitis suggests that glucocorticoids may exert a greater influence on eosinophils, thereby making them more effective in the treatment of polyps or chronic sinusitis.

OBJECTIVES

The GR immunoreactivity of eosinophils in nasal polyps was investigated to elucidate the mechanism by which glucocorticoids interact with eosinophils.

MATERIALS AND METHODS

Nasal polyp specimens were divided into 3 groups: 7 patients with chronic sinusitis alone (CS only group), 12 patients with chronic sinusitis complicated by perennial allergic rhinitis (CS/AR group), and 6 patients with chronic sinusitis complicated by bronchial asthma except for aspirin-induced asthma (CS/asthma group). Immunofluorescent staining with an anti-GR polyclonal antibody and anti-major basic protein (MBP) monoclonal antibody was used.

RESULTS

The total number of MBP+ cells, GR+ cells, and MBP+/GR+ cells in the CS/asthma group was significantly higher than that in the other two groups. The total number of these cells in the CS/AR group was also higher than that in the CS only group The ratio of MBP+/GR+ cells to GR+ cells was highest in the CS/asthma group. The ratio of MBP+/GR+ cells to MBP+ cells in the CS only group was lower than those in the other two groups.

Regulation of glucocorticoid receptor in nasal polyps by systemic and intranasal glucocorticoids

BACKGROUND

Poor response of nasal polyps to glucocorticoids (GCs) may be because of abnormal expression of GC receptors (GR) alpha and beta or to downregulation of GRalpha. We aimed to evaluate the in vivo regulation of GR isoforms in GC-treated nasal polyps and to assess the relationship between clinical response to GCs and GR levels.

METHODS

Patients with nasal polyps were randomly (3:1) treated (n = 51) or not (n = 14) with oral prednisone and intranasal budesonide for 2 weeks, plus intranasal budesonide for 10 additional weeks. Nasal symptoms were evaluated. Biopsies were obtained before (w0) and after 2 (w2) and 12 (w12) weeks of treatment, and analysed for their inflammatory content and GR mRNA (10(2) cDNA copies/mug total RNA) and protein (% immunoreactive inflammatory cells) expression. Healthy nasal mucosa (n = 11) was also investigated. Data are presented as median and 25-75th percentile.

RESULTS

At w0, nasal polyps expressed less GRalpha mRNA (1343;683-2263; P < 0.05) and GR protein (41;29-54; P < 0.05) than nasal mucosa (2474;1346-2933; 60;51-72, respectively). GRbeta immunoreactivity was higher in nasal polyps (11;4-19; P < 0.05) than in nasal mucosa (5;2-5). At w2, increased GRalpha mRNA (2010;1037-2732; P < 0.01) and GR protein (56;27-71; P = 0.056) were found compared with w0 (1177;759-2058; 37;29-55, respectively). At w12, GRalpha mRNA and GR protein were similar to w0. GRbeta expression was unaltered by treatment. Neither GRalpha nor GRbeta correlated with nasal symptoms. GR immunoreactivity negatively correlated with eosinophils (r = -0.478; P < 0.001).

CONCLUSIONS

GRalpha is downregulated in nasal polyps and upregulated by GC treatment. Neither GRalpha nor GRbeta appear to determine the sensitivity to GCs in nasal polyposis.

Alpha and beta glucocorticoid receptors: relevance in airway diseases

Glucocorticoids (GCs) are the most common and effective drugs for treating inflammatory airway respiratory diseases. Despite their efficacy, some patients respond poorly to GC treatment. Alterations in the expression of the receptor that mediates GC actions, the glucocorticoid receptor (GR), are one of the potential mechanisms that would explain GC insensitivity. In this review, we present an update on the GR gene and its products, namely GRalphaand GRbeta, as well as their alterations in disease. GRalpha has a widespread distribution and is responsible for the induction and repression of target genes, whereas GRbeta can act as a dominant negative inhibitor of GRalpha-mediated transactivation and transrepression. Very low GRbeta mRNA levels have been detected in a number of cells and tissues, which often contradict GRbeta protein data. Nevertheless, an association between GC insensitivity and increased GRbeta expression has been reported in asthma, nasal polyposis, and ulcerative colitis, and in vitro, certain pro-inflammatory cytokines upregulate GRbeta expression. However, the role of GRbeta in modulating GC sensitivity in vivo has been highly debated and is as yet unclear.

Increased glucocorticoid receptor beta alters steroid response in glucocorticoid-insensitive asthma

RATIONALE

Glucocorticoids (GCs) are highly effective in the treatment of asthma. However, some individuals have GC-insensitive asthma.

OBJECTIVES

To evaluate the functional response to steroids of bronchoalveolar lavage (BAL) cells from sites of airway inflammation from patients with GC-insensitive versus GC-sensitive asthma. As well, to attempt to define the functional role of glucocorticoid receptor (GCR)beta (a splicing variant, and dominant negative inhibitor of, the classic GCRalpha) in controlling GCRalpha nuclear translocation and transactivation at a molecular level.

METHODS AND MEASUREMENTS

Fiberoptic bronchoscopy with collection of BAL fluid was performed on seven patients with GC-sensitive asthma and eight patients with GC-insensitive asthma. GCRalpha cellular shuttling in response to 10(-6) M dexamethasone treatment and GCRbeta expression were analyzed in BAL cells by immunofluorescence staining. The effects of overexpression and silencing of GCRbeta mRNA on GCRalpha function were assessed.

MAIN RESULTS

Significantly reduced nuclear translocation of GCRalpha in response to steroids was found in BAL cells from patients with GC-insensitive asthma. BAL macrophages from patients with GC-insensitive asthma had significantly increased levels of cytoplasmic and nuclear GCRbeta. It was demonstrated that GCRalpha nuclear translocation and its transactivation properties were proportionately reduced by level of viral transduction of the GCRbeta gene into the DO-11.10 cell line. RNA silencing of GCRbeta mRNA in human BAL macrophages from patients with GC-insensitive asthma resulted in enhanced dexamethasone-induced GCRalpha transactivation.

CONCLUSIONS

GC insensitivity is associated with loss of GCRalpha nuclear translocation in BAL cells and elevated GCRbeta, which may inhibit GCRalpha transactivation in response to steroids.

Pathophysiological effects of glucocorticoids on nasal polyps: an update

PURPOSE OF REVIEW

The exact mechanisms by which glucocorticoids exert their beneficial effects on nasal polyps are not clearly defined. Nasal polyps, asthma and allergic rhinitis share common features such as mucosal infiltration with eosinophils and mast cells as well as local IgE production. The present review is an update on the pathophysiological mechanisms of glucocorticoids on nasal polyps described during the last 2 years.

RECENT FINDINGS

The reduction of leukocyte numbers in nasal polyps following glucocorticoid treatment depends on several mechanisms, for example altered balance between the two isoforms of the human glucocorticoid receptors, GRalpha and GRbeta. Another explanation may be inhibition of CD4+ T by CD8+ T cells. Increased expression of the antiinflammatory cytokine transforming growth factor beta may contribute to this. A DNA microarray study which examined the expression of some 22 000 genes showed increased expression of several antiinflammatory genes in nasal polyps after treatment with glucocorticoids. The antiinflammatory gene that increased most was uteroglobin (also known as Clara cell protein 16) which is abundantly expressed in airway secretions and thought to have an important role in regulating inflammation.

SUMMARY

Glucocorticoids affect both pro and antiinflammatory pathways in nasal polyps. Upregulation of antiinflammatory genes such as transforming growth factor beta and uteroglobin may play an important role. Elucidation of these mechanisms may help us to understand not only the effects of glucocorticoids on nasal polyps, but also on related disorders such as allergic rhinitis and asthma.

Glucocorticoid receptors in human airways

Inhaled and intranasal glucocorticoids are the most common and effective drugs for controlling symptoms and airway inflammation in respiratory diseases such as asthma, allergic rhinitis, and nasal polyposis. The last few years have seen a growing understanding of the mechanisms of glucocorticoid action and, in particular, the receptor that mediates glucocorticoid actions, the glucocorticoid receptor (GR). In this revision we present an update on the GR gene, the expression and regulation of its gene products, namely GRalpha and GRbeta, as well as their alterations in pathological states. GRalpha is responsible for the induction and repression of target genes, it is expressed in virtually all human cells and tissues, and its expression is known to be downregulated by glucocorticoids. GRbeta has been found to act as a dominant negative inhibitor of GRalpha-mediated transactivation in in vitro studies with transfected cells, but it does not appear to have a significant inhibitory effect on GRalpha-mediated transrepression. In addition, for most tissues the expression of GRbeta, at least at the mRNA level, is extremely low compared with that of GRalpha. Some pro-inflammatory cytokines appear to upregulate the expression of GRbeta, and increased GRbeta expression has been reported in diseases associated with glucocorticoid resistance or insensitivity, such as bronchial asthma, nasal polyposis, and ulcerative colitis. However, the possible role of GRbeta in modulating glucocorticoid sensitivity and/or resistance in vivo has been highly debated and it is not yet clear.

Glucocorticoid Receptor Isoforms α and β inin VitroCytokine-induced Glucocorticoid Insensitivity

We stimulated peripheral blood mononuclear cells from 14 healthy subjects, 14 patients with stable asthma, and 13 patients with unstable asthma with interleukin (IL)-2 and IL-4 to induce glucocorticoid insensitivity and we examined the relationship between insensitivity and the expression of glucocorticoid receptor (GR) isoforms. Results are expressed as IC(50) (nanomolar) values (means +/- SD) in proliferation assays and as 10(3) cDNA molecules per microgram of total RNA (means +/- SD) in real-time polymerase chain reaction analysis. Cells from patients with unstable asthma were less sensitive (316 +/- 7 nM) to dexamethasone antiproliferative effects than those from healthy control subjects (102 +/- 4 nM, p < 0.05) and patients with stable asthma (107 +/- 2 nM, p < 0.05). Coincubation with IL-2 and IL-4 repressed the inhibitory effect of dexamethasone on proliferation in all groups (unstable: 851 +/- 47 nM, p < 0.01; stable: 912 +/- 52 nM, p = 0.001; control subjects: 537 +/- 45 nM, p = 0.001). GR-alpha mRNA baseline expression was higher in patients with unstable asthma [(1.95 +/- 0.40) x 10(3) cDNA molecules/microg total RNA, p < 0.05] than in patients with stable asthma [(1.46 +/- 0.35) x 10(3) cDNA molecules/microg total RNA] and healthy subjects [(1.35 +/- 0.25) x 10(3) cDNA molecules/microg total RNA]. GR-beta mRNA was 600 times lower than GR-alpha in the three groups. Coincubation with IL-2 and IL-4 significantly increased GR-alpha mRNA expression in the three groups (p < 0.01), but caused no significant change in GR-beta mRNA. GR-alpha, but not GR-beta, protein was detected at baseline and after cytokine exposure. Our data do not support the hypothesis that increased GR-beta expression can contribute to cytokine-induced glucocorticoid insensitivity.

Quantification and glucocorticoid regulation of glucocorticoid receptor transcripts in two human leukemic cell lines

We have quantified the basal and glucocorticoid-regulated levels of different transcripts from the human glucocorticoid receptor (GR) gene in the T-cell acute lymphoblastic leukemia cell line, CEM-C7, and in the B lymphoblastoid cell line, IM-9. Highly specific quantitative, reverse transcription-polymerase chain reaction assays measured total GR transcripts, transcripts encoding the isoforms glucocorticoid receptor alpha (GRalpha) and glucocorticoid receptor beta (GRbeta), and transcripts containing different forms of exon 1: 1A1, 1A2, 1A3, 1B, and 1C. GRalpha and GRbeta transcripts are coordinately upregulated in CEM-C7 cells and coordinately downregulated in IM-9 cells by dexamethasone. The concentration of GRalpha mRNA is more than a 1000-fold higher than that for GRbeta mRNA. Transcripts with different exon 1 forms are all upregulated in CEM-C7 cells and all downregulated in IM-9 cells by dexamethasone, but transcripts containing exons 1A1, 1A2, or 1A3 are regulated to a higher degree than transcripts containing exon 1B or exon 1C. However, exon 1B- and exon 1C-containing transcripts are substantially more abundant than exon 1A-containing transcripts, with exon 1A3-containing transcripts more abundant than exon 1A1- or exon 1A2-containing transcripts. Analysis using models for glucocorticoid receptor autoregulation kinetics suggests that the minor 1A3-containing transcript component could be important for GR protein upregulation, and hence apoptosis, in CEM-C7 cells. These studies suggest that GRalpha transcripts containing exons 1A3, 1B, and 1C contribute most to the intracellular level of GR mRNA and may be the most relevant for steroid-mediated apoptosis in T-lymphoblasts.