title: Rhinovirus infection causes steroid resistance in airway epithelium through nuclear factor κB and c-Jun N-terminal kinase activation.
abstract: BACKGROUND
  Although inhaled glucocorticoids are the mainstays of asthma treatment, they are poorly effective at treating and preventing virus-induced asthma exacerbations. The major viruses precipitating asthma exacerbations are rhinoviruses.
  
  
  OBJECTIVE
  We sought to evaluate whether rhinovirus infection interferes with the mechanisms of action of glucocorticoids.
  
  
  METHODS
  Cultured primary human bronchial or transformed (A549) respiratory epithelial cells were infected with rhinovirus 16 (RV-16) before dexamethasone exposure. Glucocorticoid receptor (GR) α nuclear translocation, glucocorticoid response element (GRE) binding, and transactivation/transrepression functional readouts were evaluated by using immunocytochemistry, Western blotting, DNA binding assays, real-time quantitative PCR, coimmunoprecipitation, and ELISA techniques. Specific inhibitors of c-Jun N-terminal kinase (JNK) and of IκB kinase (IKK) were used to investigate the involvement of intracellular signaling pathways.
  
  
  RESULTS
  RV-16 infection impaired dexamethasone-dependent (1) inhibition of IL-1β-induced CXCL8 release, (2) induction of mitogen-activated protein kinase phosphatase 1 gene expression, and (3) binding of GR to GREs in airway epithelial cells. This was associated with impaired GRα nuclear translocation, as assessed by means of both immunochemistry (54.0% ± 6.8% vs 24.7% ± 3.8% GR-positive nuclei after 10 nmol/L dexamethasone treatment in sham- or RV-16-infected cells, respectively; P < .01) and Western blotting. RV-16 infection induced nuclear factor κB activation and GRα phosphorylation, which were prevented by inhibitors of IKK2 and JNK, respectively. In rhinovirus-infected cells the combination of JNK and IKK2 inhibitors totally restored dexamethasone suppression of CXCL8 release, induction of mitogen-activated protein kinase phosphatase 1 gene expression, and GRα nuclear translocation.
  
  
  CONCLUSIONS
  RV-16 infection of human airway epithelium induces glucocorticoid resistance. Inhibition of RV-16-induced JNK and nuclear factor κB activation fully reversed rhinovirus impairment of both GRα nuclear translocation and the transactivation/transrepression activities of glucocorticoids.
authors.affiliation: Section of Respiratory Diseases, Department of Medical Sciences, University of Ferrara, Ferrara, Italy. Electronic address: ppa@unife.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Papi
authors.forename: Marco
authors.initials: M
authors.lastname: Contoli
authors.forename: Ian M
authors.initials: IM
authors.lastname: Adcock
authors.forename: Cinzia
authors.initials: C
authors.lastname: Bellettato
authors.forename: Anna
authors.initials: A
authors.lastname: Padovani
authors.forename: Paolo
authors.initials: P
authors.lastname: Casolari
authors.forename: Luminita A
authors.initials: LA
authors.lastname: Stanciu
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Barnes
authors.forename: Sebastian L
authors.initials: SL
authors.lastname: Johnston
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ito
authors.forename: Gaetano
authors.initials: G
authors.lastname: Caramori
mesh_terms: D001249:Asthma / Q000150:complications / Q000188:drug therapy / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use; D004351:Drug Resistance; D004789:Enzyme Activation; D005938:Glucocorticoids / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D053583:Interleukin-1beta / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D010850:Picornaviridae Infections / Q000150:complications / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000821:virology*; D012229:Rhinovirus
chemical_list: D005938:Glucocorticoids; D053583:Interleukin-1beta; D016209:Interleukin-8; D016328:NF-kappa B; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone; D051550:I-kappa B Kinase; D048031:JNK Mitogen-Activated Protein Kinases
keywords: Asthma; EC(50); Emax; GAPDH; GR; GRE; Glucocorticoid receptor; Glucocorticoid response element; Glyceraldehyde-3-phosphate dehydrogenase; HBEC; Human bronchial epithelial cell; ICAM-1; ICS; IKK; Inhaled corticosteroid; Intercellular adhesion molecule 1; IκB kinase; JNK; MKP-1; MOI; Maximal effective concentration; Median effective concentration; Mitogen-activated protein kinase phosphatase; Multiplicity of infection; NF-κB; Nuclear factor κB; RV-16; RV-1B; Rhinovirus 16; Rhinovirus type 1B; Small interfering RNA; c-Jun N-terminal kinase; glucocorticoids; kinases; siRNA; transcription factors; viral respiratory tract infections