title: Thiol redox disturbances in children with severe asthma are associated with posttranslational modification of the transcription factor nuclear factor (erythroid-derived 2)-like 2.
abstract: BACKGROUND
  Airway thiol redox disturbances, including depletion of the antioxidant, glutathione, are differentiating features of severe asthma in children.
  
  
  OBJECTIVE
  Given the role of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in maintaining glutathione homeostasis and antioxidant defense, we quantified expression and activity of Nrf2 and its downstream targets in the airways and systemic circulation of children with asthma. We hypothesized that Nrf2 activation and function would be impaired in severe asthma, resulting in depletion of thiol pools and insufficient glutathione synthesis and conjugation.
  
  
  METHODS
  PBMCs and airway lavage cells were collected from children 6 to 17 years with severe (n = 51) and mild-to-moderate asthma (n = 38). The thiols glutathione and cysteine were quantified, and expression and activity of Nrf2 and its downstream targets were assessed.
  
  
  RESULTS
  Children with severe asthma had greater oxidation and lower concentrations of glutathione and cysteine in the plasma and airway lavage. Although Nrf2 mRNA and protein increased in severe asthma as a function of increased thiol oxidation, the Nrf2 expressed was highly dysfunctional. Nrf2 activation and downstream targets of Nrf2 binding, including glutathione-dependent enzymes, were not different between groups. The duration of asthma was a key factor associated with Nrf2 dysfunction in severe asthma.
  
  
  CONCLUSIONS
  Children with severe asthma have a global disruption of thiol redox signaling and control in both the airways and systemic circulation that is associated with posttranslational modification of Nrf2. We conclude that the Nrf2 pathway is disrupted in severe asthma as a function of chronic oxidative stress, which ultimately inhibits glutathione synthesis and antioxidant defense.
authors.affiliation: Department of Pediatrics, Emory University, Atlanta, GA, USA. anne.fitzpatrick@emory.edu
authors.forename: Anne M
authors.initials: AM
authors.lastname: Fitzpatrick
authors.forename: Susan T
authors.initials: ST
authors.lastname: Stephenson
authors.forename: Graham R
authors.initials: GR
authors.lastname: Hadley
authors.forename: Leandrea
authors.initials: L
authors.lastname: Burwell
authors.forename: Madhuri
authors.initials: M
authors.lastname: Penugonda
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Simon
authors.forename: Jason
authors.initials: J
authors.lastname: Hansen
authors.forename: Dean P
authors.initials: DP
authors.lastname: Jones
authors.forename: Lou Ann S
authors.initials: LA
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000975:Antioxidants / Q000378:metabolism; D001249:Asthma / Q000235:genetics / Q000378:metabolism*; D002648:Child; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D000072019:Kelch-Like ECH-Associated Protein 1; D008297:Male; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D012333:RNA, Messenger; D013438:Sulfhydryl Compounds; D005978:Glutathione