Exogenous Heparan Sulfate Enhances the TGF-β3-Induced Chondrogenesis in Human Mesenchymal Stem Cells by Activating TGF-β/Smad Signaling

Figure 4

SB431542 blocks HS-activated TGF-β3-mediated Smad2/3 phosphorylation. Cells were cultured in control medium supplemented with TGF-β3 (T), SB431542 treated for 2 h before treatment with TGF-β3 (T + SB), TGF-β3 together with HS (T + HS), or SB431542 treated for 2 h before treatment with TGF-β3 together with HS (T + HS + SB). Samples were harvested at 24 h. (a) Western blot for protein levels of P-Smad2/3, total Smad2/3, and GAPDH. (b) Quantification of protein levels of P-Smad2/3 normalized to total levels of Smad2/3. Error bars represent the means ± SD, . versus T + SB group, versus T + HS + SB group, and versus T group.

(a)

(b)