Enhanced oxidative stress in smoking and ex-smoking severe asthma in the U-BIOPRED cohort

Emma, Rosalia; Bansal, Aruna T.; Kolmert, Johan; Wheelock, Craig E.; Dahlen, Swen-Erik; Loza, Matthew J.; De Meulder, Bertrand; Lefaudeux, Diane; Auffray, Charles; Dahlen, Barbro; Bakke, Per S.; Chanez, Pascal; Fowler, Stephen J.; Horvath, Ildiko; Montuschi, Paolo; Krug, Norbert; Sanak, Marek; Sandstrom, Thomas; Shaw, Dominick E.; Fleming, Louise J.; Djukanovic, Ratko; Howarth, Peter H.; Singer, Florian; Sousa, Ana R.; Sterk, Peter J.; Corfield, Julie; Pandis, Ioannis; Chung, Kian F.; Adcock, Ian M.; Lutter, René; Fabbella, Lorena; Caruso, Massimo; U-BIOPRED Study Group

Abstract

Oxidative stress is believed to be a major driver of inflammation in smoking asthmatics. The U-BIOPRED project recruited a cohort of Severe Asthma smokers/ex-smokers (SAs/ex) and non-smokers (SAn) with extensive clinical and biomarker information enabling characterization of these subjects. We investigated oxidative stress in severe asthma subjects by analysing urinary 8-iso-PGF2α and the mRNA-expression of the main pro-oxidant (NOX2; NOSs) and anti oxidant (SODs; CAT; GPX1) enzymes in the airways of SAs/ex and SAn. All the severe asthma U-BIOPRED subjects were further divided into current smokers with severe asthma (CSA), ex-smokers with severe asthma (ESA) and non-smokers with severe asthma (NSA) to deepen the effect of active smoking. Clinical data, urine and sputum were obtained from severe asthma subjects. A bronchoscopy to obtain bronchial biopsy and brushing was performed in a subset of subjects. The main clinical data were analysed for each subset of subjects (urine-8-iso-PGF2α; IS-transcriptomics; BB-transcriptomics; BBrtranscriptomics). Urinary 8-iso-PGF2α was quantified using mass spectrometry. Sputum, bronchial biopsy and bronchial brushing were processed for mRNA expression microarray analysis. Urinary 8-iso-PGF2α was increased in SAs/ex, median (IQR) = 31.7 (24.5±44.7) ng/mmol creatinine, compared to SAn, median (IQR) = 26.6 (19.6±36.6) ng/mmol creatinine (p< 0.001), and in CSA, median (IQR) = 34.25 (24.4±47.7), vs. ESA, median (IQR) = 29.4 (22.3±40.5), and NSA, median (IQR) = 26.5 (19.6±16.6) ng/mmol creatinine (p = 0.004). Sputum mRNA expression of NOX2 was increased in SAs/ex compared to SAn (probe sets 203922_PM_s_at fold-change = 1.05 p = 0.006; 203923_PM_s_at fold-change = 1.06, p = 0.003; 233538_PM_s_at fold-change = 1.06, p = 0.014). The mRNA expression of antioxidant enzymes were similar between the two severe asthma cohorts in all airway samples. NOS2 mRNA expression was decreased in bronchial brushing of SAs/ex compared to SAn (fold-change = -1.10; p = 0.029). NOS2 mRNA expression in bronchial brushing correlated with FeNO (Kendal's Tau = 0.535; p< 0.001). From clinical and inflammatory analysis, FeNO was lower in CSA than in ESA in all the analysed subject subsets (p< 0.01) indicating an effect of active smoking. Results about FeNO suggest its clinical limitation, as inflammation biomarker, in severe asthma active smokers. These data provide evidence of greater systemic oxidative stress in severe asthma smokers as reflected by a significant changes of NOX2 mRNA expression in the airways, together with elevated urinary 8-iso-PGF2α in the smokers/ex-smokers group.

Citation

Emma, R., Bansal, A. T., Kolmert, J., Wheelock, C. E., Dahlen, S., Loza, M. J., …U-BIOPRED Study Group. (2018). Enhanced oxidative stress in smoking and ex-smoking severe asthma in the U-BIOPRED cohort. PLoS ONE, 13(9), 1-16. https://doi.org/10.1371/journal.pone.0203874

• Journal Article Type: Article
• Acceptance Date: Aug 29, 2018
• Online Publication Date: Sep 21, 2018
• Publication Date: Sep 21, 2018
• Deposit Date: Sep 26, 2018
• Publicly Available Date: Sep 26, 2018
• Journal: PLOS ONE
• Electronic ISSN: 1932-6203
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 9
• Article Number: e0203874
• Pages: 1-16
• DOI: https://doi.org/10.1371/journal.pone.0203874
• Keywords: General Biochemistry, Genetics and Molecular Biology; General Agricultural and Biological Sciences; General Medicine
• Public URL: https://nottingham-repository.worktribe.com/output/1134050
• Publisher URL: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203874