Mechanism of cigarette smoke condensate-induced acute inflammatory response in human bronchial epithelial cells

Respir Res. 2002;3(1):22. doi: 10.1186/rr172. Epub 2002 Jul 10.


Background: To demonstrate the involvement of tobacco smoking in the pathophysiology of lung disease, the responses of pulmonary epithelial cells to cigarette smoke condensate (CSC) - the particulate fraction of tobacco smoke - were examined.

Methods: The human alveolar epithelial cell line A549 and normal human bronchial epithelial cells (NHBEs) were exposed to 0.4 microg/ml CSC, a concentration that resulted in >90% cell survival and <5% apoptosis. Changes in gene expression and signaling responses were determined by RT-PCR, western blotting and immunocytofluorescence.

Results: NHBEs exposed to CSC showed increased expression of the inflammatory mediators sICAM-1, IL-1beta, IL-8 and GM-CSF, as determined by RT-PCR. CSC-induced IL-1beta expression was reduced by PD98059, a blocker of mitogen-actived protein kinase (MAPK) kinase (MEK), and by PDTC, a NFkappaB inhibitor. Analysis of intracellular signaling pathways, using antibodies specific for phosphorylated MAPKs (extracellular signal-regulated kinase [ERK]-1/2), demonstrated an increased level of phosphorylated ERK1/2 with increasing CSC concentration. Nuclear localization of phosphorylated ERK1/2 was seen within 30 min of CSC exposure and was inhibited by PD98059. Increased phosphorylation and nuclear translocation of IkappaB was also seen after CSC exposure. A549 cells transfected with a luciferase reporter plasmid containing a NFkappaB-inducible promoter sequence and exposed to CSC (0.4 microg/ml) or TNF-alpha (50 ng/ml) had an increased reporter activity of approximately 2-fold for CSC and 3.5-fold for TNF-alpha relative to untreated controls.

Conclusion: The acute phase response of NHBEs to cigarette smoke involves activation of both MAPK and NFkappaB.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bronchi / metabolism*
  • Bronchi / pathology*
  • Bronchi / physiopathology
  • Cells, Cultured
  • Humans
  • Inflammation / genetics
  • Inflammation / metabolism
  • Inflammation Mediators / physiology*
  • Mitogen-Activated Protein Kinase Kinases / biosynthesis
  • Mitogen-Activated Protein Kinase Kinases / genetics
  • Mitogen-Activated Protein Kinase Kinases / physiology
  • Respiratory Mucosa / metabolism*
  • Respiratory Mucosa / pathology*
  • Respiratory Mucosa / physiopathology
  • Smoke / adverse effects*
  • Smoking / adverse effects
  • Smoking / metabolism*
  • Smoking / pathology*


  • Inflammation Mediators
  • Smoke
  • Mitogen-Activated Protein Kinase Kinases