Exaggerated activation of nuclear factor-kappaB and altered IkappaB-beta processing in cystic fibrosis bronchial epithelial cells.
In cystic fibrosis (CF), inflammatory mediator production by airway epithelial cells is a critical determinant of chronic airway inflammation. To determine whether altered signal transduction through the nuclear factor (NF)-kappaB pathway occurs in CF epithelial cells and results in excessive generation of inflammatory cytokines, we evaluated tumor necrosis factor (TNF)-alpha-induced production of the NF-kappaB-dependent cytokine interleukin (IL)-8 and activation of NF-kappaB in three different human bronchial epithelial cell lines: (1) BEAS cells that express wild-type CF transmembrane conductance regulator (CFTR), (2) IB3 cells with mutant CFTR, and (3) C38 cells, which are "corrected" IB3 cells complemented with wild-type CFTR. Treatment of cells with TNF-alpha (30 ng/ml) resulted in markedly elevated NF-kappaB activation and production of IL-8 by IB3 cells compared with BEAS and C38 cells. Despite the differences in NF- kappaB activation, no differences in basal levels of IkappaB-alpha or TNF-alpha- induced IkappaB-alpha processing and degradation were detected among the cell lines. In contrast, the basal level of IkappaB-beta was increased in the IB3 cells. Treatment with TNF-alpha resulted in increased formation of hypophosphorylated IkappaB-beta and increased nuclear localization of IkappaB-beta in IB3 cells compared with the other cell types. These findings provide additional evidence of a dysregulated inflammatory response in CF.
Venkatakrishnan
A
A
Department of Medicine, Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, and Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA.
Stecenko
A A
AA
King
G
G
Blackwell
T R
TR
Brigham
K L
KL
Christman
J W
JW
Blackwell
T S
TS
D001980:Bronchi / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D003550:Cystic Fibrosis / Q000276:immunology* / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D020672:I-kappa B Proteins / Q000276:immunology / Q000378:metabolism*; D015151:Immunoblotting; D016209:Interleukin-8 / Q000378:metabolism; D008025:Ligases / Q000378:metabolism; D016296:Mutagenesis / Q000502:physiology; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D020545:Respiratory Mucosa / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
C505032:CFTR protein, human; D020672:I-kappa B Proteins; D016209:Interleukin-8; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases