Peripheral blood and airway tissue expression of transforming growth factor beta by neutrophils in asthmatic subjects and normal control subjects.
BACKGROUND
Airway remodeling may play an important role in asthma pathophysiology. Transforming growth factor beta (TGF-beta) has a critical role in the remodeling process. Although cellular sources for TGF-beta have been previously investigated in asthma airways, the expression, release, or both of TGF-beta from asthmatic airways and blood neutrophils has not been reported.


OBJECTIVE
The current study evaluated the TGF-beta protein and messenger (m)RNA expression by airway and peripheral blood neutrophils in asthmatic and normal subjects.


METHODS
TGF-beta protein expression by airway and peripheral blood neutrophils was detected by using immunocytochemistry. TGF-beta protein levels in blood neutrophil supernatant were measured by using an enzyme immunoassay. TGF-beta mRNA expression was evaluated by using reverse transcription-PCR.


RESULTS
Higher numbers of TGF-beta(+) cells and neutrophils were found in airway tissue of asthmatic (n = 15) compared with normal subjects (n = 10). Although neutrophils in both asthmatic and normal airway tissue expressed TGF-beta protein and the percentage of neutrophils expressing TGF-beta was similar between the two groups, the total number of TGF-beta(+) neutrophils was higher in the asthmatic subjects (P =.01). Peripheral blood neutrophils from asthmatic (n = 5) and normal subjects (n = 7) also expressed TGF-beta protein and mRNA. Blood neutrophils from asthmatic subjects spontaneously released significantly higher levels of TGF-beta than those from normal subjects (P =.007).


CONCLUSIONS
These data suggest that airway and blood neutrophils from both asthmatic and normal subjects can express and release TGF-beta. Higher levels of TGF-beta expression-release from asthmatic neutrophils indicate that neutrophils may be involved in the airway remodeling process of asthmatic subjects.
Chu
H W
HW
Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA.
Trudeau
J B
JB
Balzar
S
S
Wenzel
S E
SE
D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001706:Biopsy; D001980:Bronchi / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D009504:Neutrophils / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000097:blood; D012333:RNA, Messenger / Q000378:metabolism; D012137:Respiratory System / Q000166:cytology*; D016212:Transforming Growth Factor beta / Q000097:blood* / Q000235:genetics
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D010196:Pancreatic Elastase