shRNA targeting β1-integrin suppressed proliferative aspects and migratory properties of airway smooth muscle cells

Dysfunction of airway smooth muscle (ASM) is an essential feature of airway remodeling in chronic asthma. However, the precise mechanisms of this pathological process have not been well studied. In previous study, we found that β1-integrin, which was dramatically upregulated in ASM cells in an asthmatic mouse model, was associated with the cell proliferation. In this study, we employed short hairpin RNA (shRNA) targeting β1-integrin to assess the effect of down-regulation of this receptor on the proliferative aspects and migratory properties of ASM cells in vitro. The cells were treated with shRNA expression vectors directed against β1-integrin, control vectors that included the blank control, empty vector without shRNA, and mismatched shRNA, respectively. The mRNA and protein expressions of β1-integrin were determined by real-time PCR and Western blotting. Cell proliferation was measured by BrdU ELISA and cell cycle by fluorescence-activated cell sorter. Cell apoptosis was detected by Annexin V-PE/7-AAD staining. Cell migration assays were evaluated by transwell assay and expression of IL-6 and IL-8 by ELISA. The results revealed that shRNA targeting β1-integrin significantly decreased the mRNA and protein expressions of β1-integrin, enhanced the proportion of cells in G0/G1 phase, decreased the proportion in S phase, promoted cell apoptosis, inhibited cell proliferation, migration, IL-6 and IL-8 secretion in vitro. In conclusion, the overexpression of β1-integrin in ASM cells is essential for airway dysfunction development because it promotes proliferative aspects and migratory properties of ASM cells. Importantly, shRNA targeting β1-integrin may provide a new approach to preventing airway remodeling in chronic asthma.