Effects of cystic fibrosis transmembrane conductance regulator and DeltaF508CFTR on inflammatory response, ER stress, and Ca2+ of airway epithelia

Am J Physiol Lung Cell Mol Physiol. 2007 Nov;293(5):L1250-60. doi: 10.1152/ajplung.00231.2007. Epub 2007 Sep 7.

Abstract

We tested whether cystic fibrosis (CF) airway epithelia have larger innate immune responses than non-CF or cystic fibrosis transmembrane conductance regulator (CFTR)-corrected cells, perhaps resulting from ER stress due to retention of DeltaF508CFTR in the endoplasmic reticulum (ER) and activation of cytosolic Ca(2+) (Ca(i)) and nuclear factor (NF)-kappaB signaling. Adenovirus infections of a human CF (DeltaF508/DeltaF508) nasal cell line (CF15) provided isogenic comparisons of wild-type (wt) CFTR and DeltaF508CFTR. In the absence of bacteria, there were no or only small differences among CF15, CF15-lacZ (beta-galactosidase-expressing), CF15-wtCFTR (wtCFTR-corrected), and CF15-DeltaF508CFTR (to test ER retention of DeltaF508CFTR) cells in NF-kappaB activity, interleukin (IL)-8 secretion, Ca(i) responses, and ER stress. Non-CF and CF primary cultures of human bronchial epithelial cells (HBE) secreted IL-8 equivalently. Upon infection with Pseudomonas aeruginosa (PA) or flagellin (key activator for airway epithelia), CF15, CF15-lacZ, CF15-wtCFTR, and CF15DeltaF508CFTR cells exhibited equal PA binding, NF-kappaB activity, and IL-8 secretion; cells also responded similarly to flagellin when both CFTR (forskolin) and Ca(i) signaling (ATP) were activated. CF and non-CF HBE responded similarly to flagellin + ATP. Thapsigargin (Tg, releases ER Ca(2+)) increased flagellin-stimulated NF-kappaB and ER stress similarly in all cells. We conclude that ER stress, Ca(i), and NF-kappaB signaling and IL-8 secretion were unaffected by wt- or DeltaF508CFTR in control and during exposure to PA, flagellin, flagellin + ATP, or flagellin + ATP + forskolin. Tg, but not wt- or DeltaF508CFTR, triggered ER stress. Previous measurements showing hyperinflammatory responses in CF airway epithelia may have resulted from cell-specific, rather than CFTR- or DeltaF508CFTR-specific effects.

Publication types

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

MeSH terms

  • Bronchi / cytology
  • Bronchi / metabolism
  • Calcium / metabolism*
  • Calcium Signaling
  • Cells, Cultured
  • Cystic Fibrosis / metabolism*
  • Cystic Fibrosis / microbiology
  • Cystic Fibrosis / pathology
  • Cystic Fibrosis Transmembrane Conductance Regulator / pharmacology*
  • Endoplasmic Reticulum / drug effects*
  • Endoplasmic Reticulum / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Flagellin / pharmacology
  • Humans
  • Inflammation
  • Interleukin-8 / metabolism
  • Microscopy, Confocal
  • Mutation / genetics
  • NF-kappa B / metabolism
  • Pseudomonas Infections / metabolism
  • Pseudomonas Infections / microbiology
  • Pseudomonas Infections / pathology
  • Pseudomonas aeruginosa / pathogenicity
  • Respiratory Mucosa / drug effects*
  • Respiratory Mucosa / metabolism

Substances

  • Interleukin-8
  • NF-kappa B
  • cystic fibrosis transmembrane conductance regulator delta F508
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Flagellin
  • Calcium