Effects of Budesonide on the Expression of the Glucocorticoid Receptor-α in Nasal Polyp Epithelial Cells

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.

The expression of 11β-hydroxysteroid dehydrogenase type 1 and 2 in nasal polyp-derived epithelial cells and its possible contribution to glucocorticoid activation in nasal polyp

BACKGROUND

The actions of glucocorticoids in target tissues depend on the local metabolism of glucocorticoids catalyzed by 11β hydroxysteroid dehydrogenase (HSD) 1 and 2. Glucocorticoids are the most effective anti-inflammatory drugs in the treatment of nasal polyps. However, the mechanisms that underlie the anti-inflammatory effects are unclear.

OBJECTIVE

The present study analyzed the expression of 11β-HSD1, 11β-HSD2, and steroidogenic enzymes (cytochrome P450, family 11, subfamily B, polypeptide 1 [CYP11B1]; cytochrome P450, family 11, subfamily A, polypeptide 1 [CYP11A1]) in nasal polyp tissues, and endogenous cortisol levels in nasal polyp-derived epithelial cells.

METHODS

The expression levels and distribution pattern of 11β-HSD1, 11β-HSD2, CYP11B1, and CYP11A1 were determined in nasal polyp tissues or nasal polyp-derived epithelial cells by using real-time polymerase chain reaction, Western blot, and immunohistochemistry testing. The expression levels of cortisol by using enzyme-linked immunosorbent assay were determined in cultured polyp-derived epithelial cells treated with adrenocorticotrophic hormone (ACTH), 11β-HSD1 inhibitor, or small interfering ribonucleic acid technique. The effect of glucocorticoids on the expression levels of these enzymes was investigated in cultured cells.

RESULTS

Expressed in nasal polyp tissues and nasal polyp-derived epithelial cells were 11β-HSD1, 11β-HSD2, CYP11B1, and CYP11A1. Cortisol production in cultured epithelial cells was decreased in cells treated with 11β-HSD1 small interfering ribonucleic acid or inhibitor, compared with nontreated cells. Cultured cells treated with adrenocorticotropic hormone induced increased cortisol production. 11β-HSD1 expression levels were upregulated in cells treated with glucocorticoid.

CONCLUSIONS

Analysis of these results indicated that 11β-HSD1 expressed in polyp-derived epithelial cells may be involved in the anti-inflammatory function of glucocorticoid in the treatment of nasal polyps, which contributes to increased levels of endogenous cortisol.