TY - JOUR
T1 - NF-κB activation and sustained IL-8 gene expression in primary cultures of cystic fibrosis airway epithelial cells stimulated with Pseudomonas aeruginosa
AU - Joseph, Theresa
AU - Look, Dwight
AU - Ferkol, Thomas
PY - 2005/3
Y1 - 2005/3
N2 - The progression of lung disease in cystic fibrosis (CF) is characterized by an exuberant inflammatory response mounted by the respiratory epithelium that is further exacerbated by bacterial infection. Recent studies have demonstrated upregulation of nuclear factor-κB (NF-κB) in response to infection in genetically modified cell culture models, which is associated with expression of interleukin (IL)-8. Using human airway epithelial cells grown in primary culture, we examined in vitro activation of NF-κB in cells isolated from five CF (ΔF508/ΔF508) and three non-CF (NCF) patients in response to Pseudomonas aeruginosa. Immunofluorescence, gel-shift, and immunoblot assays demonstrated a rapid translocation of NF-κB subunits (p50 and p65) to the nucleus in both CF and NCF cell cultures. However, nuclear extracts from CF cells both before and following P. aeruginosa stimulation revealed elevated NF-κB activation compared with NCF cells. Additionally, elevated nuclear levels of the NF-κB inhibitor IκBα were detected in nuclei of CF cells after P. aeruginosa stimulation, but this increase was transient. There was no difference in IL-8 mRNA levels between CF and NCF cells early after stimulation, whereas expression was higher and sustained in CF cells at later times. Our results also demonstrated increased baseline translocation of NF-κB to nuclei of primary CF epithelial cell cultures, but intranuclear IκBα may initially block its effects following P. aeruginosa stimulation. Thus, IL-8 mRNA expression was prolonged after P. aeruginosa stimulation in CF epithelial cells, and this sustained IL-8 expression may contribute to the excessive inflammatory response in CF.
AB - The progression of lung disease in cystic fibrosis (CF) is characterized by an exuberant inflammatory response mounted by the respiratory epithelium that is further exacerbated by bacterial infection. Recent studies have demonstrated upregulation of nuclear factor-κB (NF-κB) in response to infection in genetically modified cell culture models, which is associated with expression of interleukin (IL)-8. Using human airway epithelial cells grown in primary culture, we examined in vitro activation of NF-κB in cells isolated from five CF (ΔF508/ΔF508) and three non-CF (NCF) patients in response to Pseudomonas aeruginosa. Immunofluorescence, gel-shift, and immunoblot assays demonstrated a rapid translocation of NF-κB subunits (p50 and p65) to the nucleus in both CF and NCF cell cultures. However, nuclear extracts from CF cells both before and following P. aeruginosa stimulation revealed elevated NF-κB activation compared with NCF cells. Additionally, elevated nuclear levels of the NF-κB inhibitor IκBα were detected in nuclei of CF cells after P. aeruginosa stimulation, but this increase was transient. There was no difference in IL-8 mRNA levels between CF and NCF cells early after stimulation, whereas expression was higher and sustained in CF cells at later times. Our results also demonstrated increased baseline translocation of NF-κB to nuclei of primary CF epithelial cell cultures, but intranuclear IκBα may initially block its effects following P. aeruginosa stimulation. Thus, IL-8 mRNA expression was prolonged after P. aeruginosa stimulation in CF epithelial cells, and this sustained IL-8 expression may contribute to the excessive inflammatory response in CF.
KW - Cystic fibrosis
KW - Interleukin-8
KW - IκB
KW - Nuclear factor-κB
UR - http://www.scopus.com/inward/record.url?scp=14944344881&partnerID=8YFLogxK
U2 - 10.1152/ajplung.00066.2004
DO - 10.1152/ajplung.00066.2004
M3 - Article
C2 - 15516493
AN - SCOPUS:14944344881
SN - 1040-0605
VL - 288
SP - L471-L479
JO - American Journal of Physiology - Lung Cellular and Molecular Physiology
JF - American Journal of Physiology - Lung Cellular and Molecular Physiology
IS - 3 32-3
ER -