Effect of IFN-γ and dexamethasone on TGF-β1- induced human fetal lung fibroblast-myofibroblast differentiation

AIM: To study whether Smads signaling pathway was involved in human fetal lung fibroblast-myofibroblast differentiation induced by transforming growth factor (TGF)-β1 and the role of interferon (IFN)-γ, dexamethasone (DEX) in the fibroblast-myofibroblast differentiation. METHODS: α-Smooth muscle actin (α-SMA), Smad2/3, and Smad7 protein were assessed by Western blot. Collagen protein was analyzed by measuring hydroxyproline. α-SMA and collagen III mRNA were assessed by RT-PCR. Myofibroblasts morphology and Smad2/3 nuclear translocation were assessed by immunohistochemistry. The overexpression of Smad7, a negative mediator of Smads signaling pathway, was acquired by transfection of Smad7 vector. RESULTS: During fibroblast-myofibroblast differentiation induced by TGF-β1, IFN-γ200 μg/L markedly blocked TGF-β1-induced α-SMA protein expression (P<0.01), collagen protein (P<0.01) and mRNA (P<0.05) expression, and myofibroblasts morphological transformation, but DEX 10μmol/L augmented TGF-β1-induced