Effect of acute and chronic inflammatory stimuli on expression of protease-activated receptors 1 and 2 in alveolar macrophages.
BACKGROUND
Protease-activated receptors 1 and 2 (PAR-1 and PAR-2) are 7-transmembrane G protein-coupled receptors activated by serine proteases in many cell types, including monocytes-macrophages, leading to the production of pro-inflammatory mediators, cytokines, and growth factors.


OBJECTIVE
We determined the influence of chronic smoking and asthma on the expression of PAR-1 and PAR-2 receptors on alveolar macrophages (AMs).


METHODS
We used RT-PCR and immunocytochemistry with confocal microscopy to determine mRNA and protein expression of PAR-1 and PAR-2 in AMs obtained from healthy smokers, asthmatic patients, and healthy subjects. In addition, we examined the effect of IL-1beta and LPS.


RESULTS
PAR1 mRNA was decreased, whereas PAR2 mRNA was increased in 24-hour cultured AMs from smokers when compared with values in AMs from healthy subjects. Paradoxically, there was a higher degree of PAR-1 protein staining in AMs from smokers, whereas PAR-2 staining was similar in smokers and healthy subjects. PAR-1 and PAR-2 mRNA and protein expression were similar in asthmatic patients and control subjects. IL-1beta and LPS had no effect on PAR1 and PAR2 gene expression by AMs.


CONCLUSIONS
There is a dissociation between gene and protein expression of PAR-1 and PAR-2. PAR-1 protein overexpression in AMs from smokers might be important in the pathophysiology of chronic airways disease.
Roche
Nicolas
N
Department of Thoracic Medicine, Imperial College School of Medicine, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, UK.
Stirling
Robert G
RG
Lim
Sam
S
Oliver
Brian G
BG
Oates
Tim
T
Jazrawi
Elen
E
Caramori
Gaetano
G
Chung
K Fan
KF
D000328:Adult; D001249:Asthma / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D016022:Case-Control Studies; D002478:Cells, Cultured; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007249:Inflammation / Q000235:genetics / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012907:Smoking / Q000235:genetics / Q000378:metabolism
D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin