Cysteine oxidation impairs systemic glucocorticoid responsiveness in children with difficult-to-treat asthma - 06/08/15
Abstract |
Background |
The mechanisms underlying glucocorticoid responsiveness are largely unknown. Although redox regulation of the glucocorticoid receptor (GR) has been reported, it has not been studied in asthmatic patients.
Objective |
We characterized systemic cysteine oxidation and its association with inflammatory and clinical features in healthy children and children with difficult-to-treat asthma. We hypothesized that cysteine oxidation would be associated with increased markers of oxidative stress and inflammation, increased features of asthma severity, decreased clinically defined glucocorticoid responsiveness, and impaired GR function.
Methods |
PBMCs were collected from healthy children (n = 16) and children with asthma (n = 118) aged 6 to 17 years. Children with difficult-to-treat asthma underwent glucocorticoid responsiveness testing with intramuscular triamcinolone. Cysteine, cystine, and inflammatory chemokines and reactive oxygen species generation were quantified, and expression and activity of the GR were assessed.
Results |
Cysteine oxidation was present in children with difficult-to-treat asthma and accompanied by increased reactive oxygen species generation and increased CCL3 and CXCL1 mRNA expression. Children with the greatest extent of cysteine oxidation had more features of asthma severity, including poorer symptom control, greater medication use, and less glucocorticoid responsiveness despite inhaled glucocorticoid therapy. Cysteine oxidation also modified the GR protein by decreasing available sulfhydryl groups and decreasing nuclear GR expression and activity.
Conclusions |
A highly oxidized cysteine redox state promotes a posttranslational modification of the GR that might inhibit its function. Given that cysteine oxidation is prevalent in children with difficult-to-treat asthma, the cysteine redox state might represent a potential therapeutic target for restoration of glucocorticoid responsiveness in this population.
Le texte complet de cet article est disponible en PDF.Key words : Biomarker, childhood asthma, treatment response, cysteine, inflammation, oxidative stress, refractory asthma, severe asthma
Abbreviations used : ACQ, Eh, GR, ROS
Plan
| Supported by National Institutes of Health (NIH) grant RO1 NR012021 and supported in part by the National Center for Advancing Translational Sciences of the NIH (award no. UL1 TR000454). |
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| Disclosure of potential conflict of interest: S. T. Stephenson, L. A. S. Brown, M. N. Helms, H. Qu, S. D. Brown, and M. R. Brown have received research support from the National Institutes of Health (NIH); National Heart, Lung, and Blood Institute (NHLBI); and National Institute of Nursing Research (NINR). A. M. Fitzpatrick has received research support from the NIH, NHLBI, and NINR and has consultant arrangements with MedImmune, Merck, GlaxoSmithKline, Genentech, and Boehringer Ingelheim. |
Vol 136 - N° 2
P. 454 - août 2015 Retour au numéro
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