Modulation of Glucocorticoid Receptor Function and Expression in Adolescent Moderate Asthma

Abstract

Background: Previous studies on adult asthmatics have shown that the disease is associated with alterations in glucocorticoid receptor (GR) function. Objectives: The aim of the present study was to examine GR functional properties in adolescent asthma of different severity. Therefore, we determined GR hormone binding parameters, e.g. the equilibrium dissociation constant (K_d) and the number of binding sites (B_max), as well as the level of receptor expression in mononuclear cells isolated from the peripheral blood of patients with mild/moderate persistent asthma. Methods: The GR hormone binding activity was assessed by whole-cell binding assay, while receptor expression was evaluated by quantitative Western blotting. Results: In peripheral blood mononuclear cells (PBMCs) of patients suffering from moderate asthma, the GR displayed higher K_d and B_max values (78.0 ± 19.5 nM and 11,715 ± 1,952 sites/cell, respectively; n = 17) in comparison to healthy subjects (23.8 ± 7.7 nM and 6,124 ± 1,369 sites/cell; n = 12) and mild asthmatics (22.4 ± 8.0 nM and 4,840 ± 776 sites/cell; n = 11). However, the GR protein level in PBMCs was found to be similar in the three study groups. Conclusion: The results provide data on GR expression and its functional status in inflammatory cells of pediatric asthmatic patients. In moderate asthma, functional characteristics of GR are altered, though the significance of these findings remains to be clarified.

Glucocorticoid receptor expression on circulating leukocytes in healthy and asthmatic adolescents in response to exercise

“…We also did not find any differences in GR mRNA expression between controls and asthmatics, although our sample size of asthmatics was small. This is consistent with previous studies where levels of GR mRNA or protein levels did not differ between healthy and asthmatic participants with varying degrees of severity ( 16 , 39 ). Perisic et al found that GR binding affinity in mononuclear cells was decreased, while the number of GR was increased, in moderate asthmatic adolescents compared to mild asthmatics and healthy subjects.…”

“…Perisic et al found that GR binding affinity in mononuclear cells was decreased, while the number of GR was increased, in moderate asthmatic adolescents compared to mild asthmatics and healthy subjects. The investigators did not examine responsiveness to steroids ( 39 ).…”

Glucocorticoid receptor alpha translational isoforms as mediators of early adversities and negative emotional states

“…Densitometry of protein bands on X-ray film was performed by the ImageJ analysis PC software. In order to minimize the variations between different blots, and to compare the protein levels between different blots, an internal reference sample (IRS) was run on each gel (Day et al, 1987; Spiliotaki et al, 2006; Perisic et al, 2009). The IRS was made as a mixture of aliquots of the control samples from the study.…”

Glucocorticoid Receptor in Health and Disease

“…Specifically, they present a higher number of GR per cell (B max ) and lower affinity of the receptor for the hormone (1/K D ). However, the GR protein level was found to be similar in PBMCs from the three groups of subjects (102). Subsequently we tested a hypothesis that GR functional alterations in asthma result from the action of oxidants.…”