Cellular proteins were extracted for western blot analysis as previously described (20 (link)). The cell lysates were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and run under standard conditions. Subsequently, the proteins were removed to polyvinylidene fluoride (PVDF) membranes. After blocking with 5% nonfat milk at room temperature for 1 h, the PVDF membranes were incubated with diluted primary antibodies SMA (1:400 dilution; sc-53142), SM22α (1:300 dilution; sc-51442) (both from Santa Cruz Biotechnology, Santa Cruz, CA, USA), FGF9 (1:800 dilution; ab9743), PDGFRβ (1:1,000 dilution; ab32570) (both from Abcam, Cambridge, MA, USA), and antibody against GAPDH (1:1,000 dilution; sc-47724; Santa Cruz Biotechnology) at 4°C overnight. The membranes were washed, further incubated for 1 h with horseradish peroxidase-conjugated secondary antibodies (anti-mouse and anti-rabbit, ZB-2305 and ZB-2305; both from Zhongshan Goldenbridge Biotechnology, Beijing, China) at 37°C. Subsequently, the membranes were detected with BeyoECL Plus (Beyotime Institute of Biotechnology, Haimen, China), and further analysis of protein band densitometry was facilitated by Quantity One software (Bio-Rad, Hercules, CA, USA).