Protein kinase R, IkappaB kinase-beta and NF-kappaB are required for human rhinovirus induced pro-inflammatory cytokine production in bronchial epithelial cells.
Rhinovirus infections cause the majority of acute exacerbations of airway diseases such as asthma and chronic obstructive pulmonary disease, with increased pro-inflammatory cytokine production by infected bronchial epithelial cells contributing to disease pathogenesis. Theses diseases are a huge cause of morbidity worldwide, and contribute a major economic burden to healthcare costs. Current steroid based treatments are only partially efficient at controlling virus induced inflammation, which remains an unmet therapeutic goal. Although NF-kappaB has been implicated, the precise mechanisms of rhinovirus induction of pro-inflammatory gene expression in bronchial epithelial cells are unclear. We hypothesised that rhinovirus replication and generation of dsRNA was an important process of pro-inflammatory cytokine induction. Using pharmalogical (2-aminopurine and a new small molecule inhibitor) and genetic inhibition of the dsRNA binding kinase protein kinase R, striking inhibition of dsRNA (polyrIC) and rhinovirus induced CCL5, CXCL8 and IL-6 protein was observed. Using confocal microscopy, rhinovirus induced protein kinase R phosphorylation co-located with NF-kappaB p65 nuclear translocation. Focusing on CXCL8, both rhinovirus infection and dsRNA treatment required IkappaB kinase-beta for induction of CXCL8. Analysis of cis-acting sites in the CXCL8 promoter revealed that both rhinovirus infection and dsRNA treatment upregulated CXCL8 promoter activation via NF-kappaB and NF-IL6 binding sites. Together, the results demonstrate the importance of dsRNA in induction of pro-inflammatory cytokines by rhinoviruses, and suggest that protein kinase R is involved in NF-kappaB mediated gene transcription of pro-inflammatory cytokines via IkappaB kinase-beta. These molecules regulating rhinovirus induction of inflammation represent therapeutic targets.
Edwards
Michael R
MR
Department of Respiratory Medicine, National Heart Lung Institute and Wright Fleming Institute of Infection and Immunity, Imperial College London, Norfolk Place, London W2 1PG, UK. michael.edwards@ic.ac.uk
Hewson
Christopher A
CA
Laza-Stanca
Vasile
V
Lau
Hoy-Tsun H
HT
Mukaida
Naofumi
N
Hershenson
Marc B
MB
Johnston
Sebastian L
SL
D015075:2-Aminopurine / Q000494:pharmacology; D001980:Bronchi / Q000737:chemistry / Q000276:immunology* / Q000821:virology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000737:chemistry / Q000276:immunology / Q000821:virology; D005786:Gene Expression Regulation; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000378:metabolism / Q000494:pharmacology; D012367:RNA, Viral / Q000378:metabolism / Q000494:pharmacology; D012229:Rhinovirus / Q000276:immunology*; D051996:Transcription Factor RelA / Q000032:analysis / Q000378:metabolism*; D019892:eIF-2 Kinase / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*
D016207:Cytokines; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D051996:Transcription Factor RelA; D015075:2-Aminopurine; D019892:eIF-2 Kinase; D051550:I-kappa B Kinase