Increased expression of collagen receptors: alpha1beta1 and alpha2beta1 integrins on blood eosinophils in bronchial asthma.
BACKGROUND
Eosinophils are one of the major effector cells in bronchial asthma. Their infiltration of airways correlates with the asthma severity. Recruitment and activation of eosinophils are partially mediated by integrins alpha4beta1 and alpha4beta7. Collagens type I and IV constitute important components of extracellular matrix and vascular basement membrane, respectively. Therefore, collagen-binding integrins (alpha1beta1 and alpha2beta1) may also play a role in eosinophil lung infiltration.


OBJECTIVE
To evaluate the possible presence of alpha1beta1 and alpha2beta1 integrins on peripheral blood eosinophils from asthmatic subjects.


METHODS
Collagen receptors were studied on eosinophils separated by immunomagnetic CD16-negative method from healthy donors (n=13) and patients with moderate persistent atopic bronchial asthma (n=15). Surface receptor identification was performed by flow cytometry and cell adhesion assay.


RESULTS
Eosinophils isolated from the patients showed increased expression of both alpha1beta1 and alpha2beta1 integrins as compared with healthy controls. Moreover, adhesive function of eosinophils to collagen type IV was inhibited by snake venom disintegrins: viperistatin and obtustatin. These disintegrins contain KTS active motif and are specific inhibitors of alpha1beta1 integrin.


CONCLUSIONS
We demonstrated for the first time that collagen receptors: alpha1beta1 and alpha2beta1 integrins are overexpressed on the surface of peripheral blood eosinophils of asthmatic subjects. Further studies may reveal potential application of KTS-disintegrins or their structural analogs for therapy of bronchial asthma.
Bazan-Socha
S
S
Department of Medicine, Jagiellonian University School of Medicine, Krakow, Poland.
Bukiej
A
A
Pulka
G
G
Marcinkiewicz
C
C
Musial
J
J
D000328:Adult; D001249:Asthma / Q000097:blood / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D024141:Collagen Type IV / Q000276:immunology; D019483:Disintegrins / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D039222:Integrin alpha1beta1 / Q000276:immunology; D038982:Integrin alpha2beta1 / Q000276:immunology; D008297:Male; D038981:Receptors, Collagen / Q000276:immunology*; D014757:Viper Venoms / Q000276:immunology
D024141:Collagen Type IV; D019483:Disintegrins; D039222:Integrin alpha1beta1; D038982:Integrin alpha2beta1; D038981:Receptors, Collagen; D014757:Viper Venoms; C474313:obtustatin, Vipera lebetina obtusa