Glucocorticoid receptor localization in normal and asthmatic lung

Abstract

The localization and distribution of the human glucocorticoid receptor (GR) mRNA and protein was investigated in human lung obtained from transplant donors and recipients by in situ hybridization, RNA blot analysis, immunolocalization, and Western analysis. Subjects were either nonasthmatic or had mild asthma requiring only beta(2)-agonists. No difference in amount of GR mRNA was found in total RNA isolated from nonasthmatic or asthmatic donor lung. In situ hybridization showed the highest concentration of GR mRNA in the alveolar walls and vascular endothelium and smooth muscle, with lesser amounts in the airway epithelium and smooth muscle. There was no change in the level or sites of expression of GR mRNA between normal and asthmatic subjects. Immunolocalization of GR confirmed the in situ hybridization data. There was no change in the level or sites of expression of GR, in either the lung or airway, between normal and asthmatic subjects. Immunolocalization of GR in bronchial biopsies from two normal and asthmatic subjects confirmed the localization and distribution of GR. Western analysis and mobility shift assays confirmed no differences in GR levels between the two subject groups. The localization of GR mRNA and protein to specific cell types within lung and airway will make it possible to study the cellular targets of glucocorticoid therapy in inflammatory lung diseases such as asthma.