Fig. 4.

SMAD3 mediates GDF-11-induced downregulation of StAR expression in hGL cells. A and B, hGL cells were transfected with 100 nM control siRNA (si-Ctrl), SMAD2 siRNA (si-SMAD2) (A), or SMAD3 siRNA (si-SMAD3) (B) for 48 h, and then treated with 30 ng/mL GDF-11 (G11) for 24 h. The mRNA levels of SMAD2, SMAD3, and StAR were determined by RT-qPCR. C, hGL cells were transfected with 100 nM control siRNA (si-Ctrl), SMAD2 siRNA (si-SMAD2), or SMAD3 siRNA (si-SMAD3) for 48 h, and then treated with 30 ng/mL GDF-11 (G11) for 24 h. The protein levels of SMAD2, SMAD3, and StAR were determined by western blot. The results are expressed as the mean ± SEM of at least three independent experiments. The values without a common letter are significantly different (p < 0.05)