Figure 4

TGFβ signaling triggered decreased expression of lipogenic genes through the TGFβ RII-Smad2 dependent pathway. (a, b) SSG3 cells were treated with 5 ng/ml of TGFβ1 for 24 hours and used for qPCR. Data were normalized to GAPDH expression and relative expression determined using untreated cells as a reference. FADS2 and PPARγ expression were found to be significantly downregulated in response to TGFβ1 treatment in SSG3 cells. (c) TGFβ RII expression in SSG3 cells expressing TGFβ RII shRNA1 and a control shRNA (Ctr) shows the efficiency of the knockdown. (d). Immunoblot confirms the decrease of p-Smad2 activity in shRNA expressing cells stimulated with TGFβ1 5ng/ml for 1 h. Values, noted below the immunoblot, represent the relative density quantified with ImageJ using the ratio p-Smad2/Smad2/3 from each condition. (e, f). Decrease of FADS2 and PPARγ at the transcriptional level is mediated via canonical Smad signal transduction. The expression was normalized to control (Ctr) untreated. The significant decrease in PPARγ and FADS2 genes in control SSG3 cells after treatment with TGFβ1, is not detected in TGFβ RII-deficient SSG3 cells. * p-value <0.05, ** p-value < 0.001 (paired two-tailed Student’s t test).