Fig. 1

SMAD3 mediates CXCL12-induced connective tissue growth factor (CTGF) expression in human lung fibroblasts (WI-38). a WI-38 cells were treated with 0.1~ 1 μM of SIS3 for 20 min before cells were exposed to CXCL12 (10 ng/ml) for additional 2 h. Protein levels of CTGF or α-tubulin in cell lysates were determined by western blot. Statistics are showed as the mean ± S.E.M. of three separate experiments. * p < 0.05, compared with CXCL12 treatment without SIS3. b After transfected with control siRNA (Con siRNA 100 nM) or SMAD3 siRNA (100 nM) for 24 h, WI-38 cells were exposed to CXCL12 (10 ng/ml) for additional 2 h. Protein levels of CTGF, SMAD3, or α-tubulin in cell lysates were determined by western blot. Statistics are showed as the mean ± S.E.M. of three separate experiments. * p < 0.05, compared with CXCL12 treatment with control siRNA. c After transfected with control siRNA (Con siRNA 25 nM), c-Jun siRNA (25 nM), SMAD3 siRNA (25 nM), 0.5 μg CTGF-Luc, and 0.2 μg of pBK-CMV-Lac Z for 24 h, the WI-38 cells were exposed to CXCL12 (10 ng/ml) for additional 24 h. The CTGF-luciferase activity assay is described in “Materials and Methods”. Statistics are showed as the mean ± S.E.M. of four separate experiments. * p < 0.05, compared to CXCL12 treatment alone. d WI-38 cells were treated with 1~ 10 μM of SB431542 for 20 min before cells were exposed to CXCL12 (10 ng/ml) for additional 2 h. Protein levels of CTGF or α-tubulin in cell lysates were determined by western blot. Statistics are showed as the mean ± S.E.M. of three separate experiments. * p < 0.05, compared with CXCL12 treatment without SB431542