Protein kinase R, IkappaB kinase-beta and NF-kappaB are required for human rhinovirus induced pro-inflammatory cytokine production in bronchial epithelial cells

Mol Immunol. 2007 Mar;44(7):1587-97. doi: 10.1016/j.molimm.2006.08.014. Epub 2006 Sep 20.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Aminopurine / pharmacology
  • Bronchi / chemistry
  • Bronchi / immunology*
  • Bronchi / virology
  • Cytokines / genetics
  • Cytokines / metabolism*
  • Epithelial Cells / chemistry
  • Epithelial Cells / immunology
  • Epithelial Cells / virology
  • Gene Expression Regulation
  • Humans
  • I-kappa B Kinase / metabolism*
  • NF-kappa B / metabolism
  • Protein Kinase Inhibitors / pharmacology
  • RNA, Double-Stranded / metabolism
  • RNA, Double-Stranded / pharmacology
  • RNA, Viral / metabolism
  • RNA, Viral / pharmacology
  • Rhinovirus / immunology*
  • Transcription Factor RelA / analysis
  • Transcription Factor RelA / metabolism*
  • eIF-2 Kinase / analysis
  • eIF-2 Kinase / antagonists & inhibitors
  • eIF-2 Kinase / metabolism*

Substances

  • Cytokines
  • NF-kappa B
  • Protein Kinase Inhibitors
  • RNA, Double-Stranded
  • RNA, Viral
  • Transcription Factor RelA
  • 2-Aminopurine
  • eIF-2 Kinase
  • I-kappa B Kinase