Abstract
Objective: It has been shown that integrins can modulate airway smooth muscle cells (ASMC) proliferation and contractile protein expression demonstrating ASMC remodelling in an animal model of allergic asthma (Dekkers et al., 2010). Despite the widely acknowledged significance of eosinophils in asthma pathogenesis, eosinophils adhesion to ASMC through integrin/ligands interaction needs to be investigated.
The aim: To investigate the role of RGD (Arg-Gly-Asp)–binding integrins on asthmatic peripheral blood eosinophils adhesion to ASMC.
Material and methods: Human airway smooth muscle cell lines immortalized by human telomerase reverse transcriptase were used for the experiments. Eosinophils were isolated from peripheral blood of 5 stable asthmatic patients free of steroids and 6 healthy subjects. For each participant an individual co-culture was prepared. Cell adhesion was evaluated after co-culture by measuring eosinophil peroxidase (EPO) activity, using eosinophils incubated alone or in presence of the integrin-blocking peptide RGDS (Arg-Gly-Asp-Ser).
Results: Eosinophils from asthmatic peripheral blood adhered rapidly to ASMC, with maximum number being observed after 30 min of co-culture, compared with healthy subjects: 118.2% (range, 13.6–175.0) vs 16.5% (range, 6.8–54.6), respectively, p<0.05. Integrin-blocking peptide significantly (p<0.05) reduced adhesion of eosinophils from asthmatic peripheral blood to ASMC (44.4%, range 5.0-138.8), however no effect was found on eosinophil adhesion in healthy subjects (17.3%, range 3.7–61.2).
Conclusion: Asthmatic peripheral blood eosinophils show increased adhesion to ASMC and blocking of RGD–binding integrins significant reduced the adhesive activity.
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