Airway epithelial cells from asthmatic children differentially express proremodeling factors.
BACKGROUND
The airway epithelium can express factors that drive subepithelial airway remodeling. TGF-β2, vascular epithelial growth factor (VEGF), a disintegrin and metalloprotease 33 (ADAM33), and periostin are hypothesized to be involved in subepithelial remodeling and are overexpressed in adult asthmatic airways. Epidemiologic data suggest that lung function deficits in asthmatic patients are acquired in childhood.


OBJECTIVE
We sought to determine whether airway epithelial cells (AECs) from asthmatic children differentially express TGF-β2, VEGF, ADAM33, or periostin compared with cells from atopic nonasthmatic and healthy children intrinsically or in response to IL-4/IL-13 stimulation.


METHODS
Bronchial and nasal epithelial cells were obtained from brushings from well-characterized asthmatic (n = 16), atopic nonasthmatic (n = 9), and healthy (n = 15) children after achievement of anesthesia for elective procedures. After differentiation at an air-liquid interface (ALI) for 3 weeks, conditioned media were sampled and RNA was extracted from unstimulated and IL-4/IL-13-stimulated cultures. TGF-β2 and VEGF levels were measured with ELISA. ADAM33 and periostin expression was assessed by using real-time PCR.


RESULTS
TGF-β2 and VEGF production was significantly greater in bronchial and nasal ALI cultures from asthmatic children than in cultures from atopic nonasthmatic and healthy children. TGF-β2 levels increased significantly in asthmatic cultures after IL-4/IL-13 stimulation. Within-subject correlation between nasal and bronchial ALI production of TGF-β2 (r = 0.64, P = .001) and VEGF (r = 0.73, P < .001) was good. Periostin expression was 3.7-fold higher in bronchial cells (P < .001) and 3.9-fold higher in nasal cells (P < .004) from asthmatic children than in cells from atopic nonasthmatic or healthy children. ADAM33 was not differentially expressed by AECs from asthmatic patients compared with that from cells from atopic nonasthmatic or healthy children.


CONCLUSIONS
AECs from asthmatic children differentially express TGF-β2, VEGF, and periostin compared with cells from atopic nonasthmatic and healthy children. Nasal epithelial cells might be a suitable surrogate for bronchial cells that could facilitate investigation of the airway epithelium in future longitudinal pediatric studies.
Center for Tissue and Cell Sciences, Seattle Children's Research Institute, Seattle, WA, USA.
Jesus M
JM
Lopez-Guisa
Claire
C
Powers
Daniele
D
File
Elizabeth
E
Cochrane
Nathalia
N
Jimenez
Jason S
JS
Debley
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D056151:Airway Remodeling; D001249:Asthma / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism*; D053781:Transforming Growth Factor beta2 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D015815:Cell Adhesion Molecules; C512835:POSTN protein, human; D012333:RNA, Messenger; D053781:Transforming Growth Factor beta2; D042461:Vascular Endothelial Growth Factor A; D051722:ADAM Proteins; C450441:ADAM33 protein, human