title: Rho/Rock cross-talks with transforming growth factor-β/Smad pathway participates in lung fibroblast-myofibroblast differentiation.
abstract: The differentiation of fibroblasts, which are promoted by transforming growth factor-β (TGF-β)/Smad, is involved in the process of pulmonary fibrosis. The Rho/Rho-associated coiled-coil-forming protein kinase (Rock) pathway may regulate the fibroblast differentiation and myofibroblast expression of α-smooth muscle actin (α-SMA), however, the mechanism is not clear. The aim of the present study was to evaluate the role of Rho/Rock and TGF-β/Smad in TGF-β1-induced lung fibroblasts differentiation. Human embryonic lung fibroblasts were stimulated by TGF-β1, Y-27632 (inhibitor of Rho/Rock signaling) and staurosporine (inhibitor of TGF-β/Smad signaling). The α-SMA expression, cell cycle progression, content of the extracellular matrix (ECM) in cell culture supernatants and the expression of RhoA, RhoC, Rock1 and Smad2 were detected. The results demonstrated that α-SMA-positive cells significantly increased following TGF-β1 stimulation. Rho/Rock and TGF-β/Smad inhibitors suppressed TGF-β1-induced lung fibroblast differentiation. The inhibitors increased G0/G1and decreased S and G2/M percentages. The concentrations of the ECM proteins in the supernatant were significantly increased by TGF-β1 stimulation, whereas they were decreased by inhibitor stimulation. RhoA, RhoC, Rock1, Smad2 and tissue inhibitor of metalloproteinase-1 were upregulated by TGF-β1 stimulation. The Rho/Rock inhibitor downregulated Smad2 expression and the TGF-β/Smad inhibitor downregulated RhoA, RhoC and Rock1 expression. Therefore, the Rho/Rock pathway and Smad signaling were involved in the process of lung fibroblasts transformation, induced by TGF-β1, to myofibroblasts. The two pathways may undergo cross-talk in the lung fibroblasts differentiationin vitro.
authors.affiliation: Department of Paediatrics, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Ji
authors.affiliation: Department of Respiratory, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Jingwei
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Respiratory, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Lili
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Respiratory, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Respiratory, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China.
authors.forename: Taihua
authors.initials: T
authors.lastname: Wu
keywords: Rho; Rho-associated coiled-coil-forming protein kinase; Smad; myofibroblast; pulmonary fibrosis; transforming growth factor-β