Fig 2: ALK5 activity but not the activation of p38 MAPK and Akt was required for TGF-β1-stimulated MYH9 induction. MRC-5 cells were co-treated with/without 2.5 ng/ml of TGF-β1, 10 μM of SB43152 (ALK5 inhibitor), 10 μM of perifosine (AKT inhibitor), and 0.5 μM of SB203580 (p38 MAPK inhibitor) for 48 h. The expression levels of MYH9 protein in different treatment groups were measured by Western blot analysis (n = 3, control group vs. TGF-β1 group: *p < 0.05; TGF-β1 group vs. ALK5 inhibitor group: # p < 0.05; TGF-β1 group vs. p38 MAPK or Akt inhibitor group: NS).

Fig 3: Knockdown of MYH9 did not change the Smad2/3 phosphorylation in TGF-β1-stimulated MRC-5 cells. MRC-5 cells were transfected with scramble or MYH9 siRNA (50 nM); 24 h after transfection, the cells were starved overnight. MRC-5 cells were treated with/without 2.5 ng/ml of TGF-β1 for 1 h. MRC-5 cell protein samples were prepared and assayed by Western blot analysis for determing the levels of Smad2/3 phosphorylation (n = 3, control group vs. TGF-β1 group: *p < 0.05; Scramble siRNA group vs. MYH9 siRNA group: NS).

Fig 4: Schematic representing the regulation of MYH9 on TGF-β1-induced myofibroblast differentiation.

Fig 5: TGF-β1 stimulated MYH9 mRNA and protein expression in MRC-5 cells. MRC-5 cells were maintained in MEM with 10% FBS and stimulated with/without 2.5 ng/ml of TGF-β1 for 48 h. MYH9 mRNA expression (A) was determined by qRT-PCR analysis, and MYH9 protein expression (B) was measured with Western blot analysis. n = 3; control group vs. TGF-β1 group: *p < 0.05.