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


CONCLUSIONS
The acute phase response of NHBEs to cigarette smoke involves activation of both MAPK and NFkappaB.
Hellermann
Gary R
GR
Division of Allergy and Immunology, Joy McCann Culverhouse Airway Disease Center, Department of Internal Medicine, University of South Florida College of Medicine, VA Hospital, Tampa 33612, USA. ghellerm@hsc.usf.edu
Nagy
Szilvia B
SB
Kong
Xiaoyuan
X
Lockey
Richard F
RF
Mohapatra
Shyam S
SS
D001980:Bronchi / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D002478:Cells, Cultured; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000378:metabolism; D018836:Inflammation Mediators / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism* / Q000473:pathology*
D018836:Inflammation Mediators; D012906:Smoke; D020929:Mitogen-Activated Protein Kinase Kinases