Effect of Rho signaling pathway on SiO2 induced α-SMA expression in human bronchial epithelial cells.

ABSTRACT

OBJECTIVE: To investigate the role of Rho in SiO2 induced α-SMA expression in human bronchial epithelial cells (HBECs). METHODS: HBECs were cultured and stimulated with SiO2. Immunocytochemistry and Western blot were used to detect the expression of α-SMA. The activity of Rho was determined by GST pull down assay. In the prevention experiment, SiO2-stimulated HBECs were incubated with Rho inhibitor Y27632, and the expression of α-SMA was examined by Western blot. RESULTS: With SiO2 (0-300 µg/mL) treatment, the expression of α-SMA increased gradually, and 200 µg/mL of SiO2 led to the highest expression of α-SMA which was (5.09±1.98) times of the expression of α-SMA in the control group(P<0.01). HBECs treated with SiO2 (200 µg/mL) for indicated time (1, 2, 6, 12, and 24 h) showed an obvious increase of Rho activity(P<0.01). Y27632 inhibited SiO2-induced α-SMA expression significantly, and the inhibition rate of 20 and 30 µmol/L Y27632 was 68% and 75%, respectively (P<0.01). CONCLUSION: Rho signaling pathway may mediate SiO2 induced α-SMA expression in HBECs.