Expression of glucocorticoid receptor mRNAs in glucocorticoid-resistant nasal polyps

Abstract

Glucocorticoids (GCs) are the most effective group of medications available to treat inflammation. Although most patients with inflammation respond to GC, a small group of patients exhibit persistent GC-resistance with prolonged inflammation. Previously, it was proposed that the GC-resistance is caused by low amount of human GC receptor (hGRα) and/or excessive presence of a GC receptor isoform, hGRβ that was generated from alternative splicing of the hGR message. We have tested this hypothesis by investigating correlation between the expression pattern of hGR mRNAs in patients with inflammatory nasal polyps and the effectiveness of GC treatment. We have performed reverse transcription PCR analysis of mRNAs coding each hGRα and hGRβ in nasal tissues. hGRα mRNA was more expressed in patients with nasal polyps than in normal subjects. However, the elevated hGRα mRNA expression was decreased after GC treatment. Compared with hGRα mRNA expression, level of hGRβ mRNA expression was very low in all groups. In patients, hGRβ mRNA was expressed at a similar level regardless of GC efficacy, indicating that there is no correlation between the GC sensitivity and the expression level of hGRβ mRNA. Thus, persistent GC-resistance is not associated with low expression of hGRa or over- expression of hGRβ.