Glucocorticoid resistance in asthma is associated with elevated in vivo expression of the glucocorticoid receptor /3-isoform. J.Allergy Clin.Immunol. 105: 943-950
Department of Respiratory Medicine and Allergy, King's College London, Guy's Hospital, London, UK. Journal of Allergy and Clinical Immunology
(Impact Factor: 11.48).
06/2000; 105(5):943-50. DOI: 10.1067/mai.2000.106486
Glucocorticoid-resistant bronchial asthma is characterized by failure of corticosteroids to suppress key asthma-relevant, cell-mediated inflammatory responses in the airways.
The mechanism of this phenomenon is not clear but may involve aberrant expression of the beta-isoform of the glucocorticoid receptor.
We have measured expression of the alpha- and beta-glucocorticoid receptor isoforms in tuberculin-driven cutaneous cell-mediated inflammatory lesions in people with asthma who are glucocorticoid sensitive and resistant after 9 days of therapy with oral prednisolone (40 mg/day) or matching placebo in a random order, crossover design.
After placebo therapy, the mean numbers of cells expressing glucocorticoid receptor alpha immunoreactivity in the lesions evoked in glucocorticoid-sensitive and -resistant patients with asthma were statistically equivalent. The numbers of cells expressing glucocorticoid receptor beta were significantly elevated in the patients who were glucocorticoid resistant, resulting in an 8-fold higher ratio of expression of glucocorticoid receptor alpha/glucocorticoid receptor beta in the patients who were glucocorticoid sensitive. Glucocorticoid receptor alpha/glucocorticoid receptors beta were colocalized to the same cells. Oral prednisolone therapy was associated with a significant decrease in the numbers of cells expressing glucocorticoid receptor alpha but not glucocorticoid receptor beta in the subjects who were glucocorticoid sensitive. No significant change was found in the numbers of cells expressing glucocorticoid receptor alpha and glucocorticoid receptor beta in the patients who were glucocorticoid resistant. Prednisolone therapy reduced the ratio of glucocorticoid receptor alpha/glucocorticoid receptor beta expression for the patients who were glucocorticoid sensitive to a level seen in the patients who were glucocorticoid resistant before therapy.
Because glucocorticoid receptor beta inhibits alpha-glucocorticoid receptor-mediated transactivation of target genes, the increased expression of glucocorticoid receptor beta in inflammatory cells might be a critical mechanism for conferring glucocorticoid resistance.
Available from: Annelise Goecke
- "GC actions are mediated through their cellular receptors. Because a dominant negative effect of GRβ was reported, a potential role for this receptor in GC-resistant states has been proposed [39-41,45]. Therefore our study evaluated the expression of GRα and β in septic patients. "
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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.
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.
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.
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.
Available from: ncbi.nlm.nih.gov
- "The biological background of prednisone response is still unknown. However, there have been investigations with respect to glucocorticoid receptors , distribution of GR isoforms , and genetic polymorphisms . Polymorphisms at the promoter region of IL10 gene are associated with several diseases, including autoimmune, infectious, cancer, Alzheimer's disease (AD), and lymphoblastic leukemia . "
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ABSTRACT: Interleukin 10 (IL10) is a pleiotropic cytokine that stimulates various hematopoietic cells. The tumor necrosis factor alpha (TNFα) is a cytokine that may influence the transcriptional activity induced by glucocorticoids. This study examined the impact of TNFα (G308A) and IL10 (G1082A) polymorphisms at promoter regions in relation to the overall survival of 105 children (0 ≤ 18 years) with acute lymphoblastic leukemia (ALL) for a period of 126 months, treated according to the protocol GBTLI99. The G1082A and G308A polymorphisms were identified by allele-specific PCR and PCR-RFLP, respectively. Patients with IL10AA genotype had a higher death ratio (44%, P = 0.0089). Patients with both IL10AA and TNFAA genotypes showed the worst survival when compared with the IL10GG and TNFGA genotypes (P = 0.0043). The results of this study revealed a lower survival among patients with IL10AA genotype and the concomitant occurrence of IL10AA and TNFAA genotypes.
Available from: jmm.sgmjournals.org
- "Although the precise cause of corticosteroid resistance is unknown, there is evidence that the development of corticosteroid-resistant or -insensitive asthma is associated with the modulation of glucocorticoid receptor (GR) function (Adcock & Barnes, 2008; Hamid et al., 1999). In addition, recent studies of asthma patients have demonstrated increased expression of GRb, an endogenous inhibitor of GC action, in PBMCs and airway T cells, and a reduced ratio of GRa positive to GRb positive cells (Hamid et al., 1999; Leung et al., 1997; Sousa et al., 2000). These findings suggest that GC insensitivity is linked to increased expression of GRb. "
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ABSTRACT: Chlamydophila pneumoniae infection has been suggested to be associated with severe asthma characterized by persistent airway limitation, which may be related to airway remodelling. We investigated whether C. pneumoniae infection affected the secretion of metalloproteinase-9 (MMP9) and tissue inhibitor metalloproteinase-1 (TIMP1), and altered the responsiveness of inflammatory cells to corticosteroids. Human peripheral blood mononuclear cells (PBMCs) were cultured in vitro in the presence or absence of C. pneumoniae. Secretion of both MMP9 and TIMP1 was strongly suppressed by dexamethasone treatment in uninfected cells. MMP9 secretion was also significantly inhibited by dexamethasone in C. pneumoniae-infected cells, but TIMP1 secretion was not; hence the MMP9 to TIMP1 ratio decreased. Interestingly, expression of human glucocorticoid receptor β, which is believed to confer resistance to corticosteroids, was enhanced by dexamethasone treatment in C. pneumoniae-infected PBMCs. We conclude that C. pneumoniae infection may promote airway remodelling by decreasing the ratio of MMP9 to TIMP1 secreted by inflammatory cells, and by altering cellular responsiveness to corticosteroids.
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