Transforming growth factor-alpha 1 (TGF-beta 1) is known to induce the transition of human lung fibroblasts to myofibroblasts, a primary event in the pathogenesis of idiopathic pulmonary fibrosis. The molecular pathways involved in myofibroblast transformation are only partially identified. We found that a 24-h treatment with TGF-beta 1 (10 ng/ml) induced alpha-smooth actin (SMA) expression and collagen production in human lung fibroblasts. These effects were abrogated by PD98059, a specific inhibitor of the mitogen-activated protein kinase (MAPK) pathway. TGF-beta 1 treatment activated the MAPK pathway, as shown by an increased phosphorylation of extracellular-regulated kinases (ERK)1/2 after 30 min of exposure. TGF-beta 1 also increased the expression of the Ser-9-phosphorylated inactive form of glycogen synthase kinase-3 beta (GSK-3 beta), an effect that was largely attenuated by PD98059. A nuclear translocation of beta-catenin in human lung fibroblasts was observed 2h after TGF-beta 1 addition both by confocal microscopy and nuclear protein analysis. At this time, TGF-beta 1 also increased the total levels of beta-catenin, an effect that was preventedby PD98059. Similarly to TGF-beta 1, the GSK-3 beta inhibitor lithium chloride (10 mM), increased the total levels of beta-catenin and promoted alpha-SMA expression and collagen production. This study demonstrates that TGF-beta 1 induces alpha-SMA expression and collagen production in human lung fibroblasts via ERK1/2 activation, GSK-3 beta inhibition and nuclear beta-catenin translocation. The evidence that the silencing of beta-catenin by siRNAs was able to prevent the induction of alpha-SMA expression in TGF-beta 1-treated fibroblasts further supports the hypothesis of a contribution of the GSK-3 beta/beta-catenin pathway in the pathogenesis of idiopathic pulmonary fibrosis

TGF-beta1 targets the GSK-3beta/beta-catenin pathway via ERK activation in the transition of human lung fibroblasts into myofibroblasts

CARACI, FILIPPO;CRIMI, Nunzio;SORTINO, Maria Angela;COPANI, Agata Graziella;VANCHERI, CARLO
2008-01-01

Abstract

Transforming growth factor-alpha 1 (TGF-beta 1) is known to induce the transition of human lung fibroblasts to myofibroblasts, a primary event in the pathogenesis of idiopathic pulmonary fibrosis. The molecular pathways involved in myofibroblast transformation are only partially identified. We found that a 24-h treatment with TGF-beta 1 (10 ng/ml) induced alpha-smooth actin (SMA) expression and collagen production in human lung fibroblasts. These effects were abrogated by PD98059, a specific inhibitor of the mitogen-activated protein kinase (MAPK) pathway. TGF-beta 1 treatment activated the MAPK pathway, as shown by an increased phosphorylation of extracellular-regulated kinases (ERK)1/2 after 30 min of exposure. TGF-beta 1 also increased the expression of the Ser-9-phosphorylated inactive form of glycogen synthase kinase-3 beta (GSK-3 beta), an effect that was largely attenuated by PD98059. A nuclear translocation of beta-catenin in human lung fibroblasts was observed 2h after TGF-beta 1 addition both by confocal microscopy and nuclear protein analysis. At this time, TGF-beta 1 also increased the total levels of beta-catenin, an effect that was preventedby PD98059. Similarly to TGF-beta 1, the GSK-3 beta inhibitor lithium chloride (10 mM), increased the total levels of beta-catenin and promoted alpha-SMA expression and collagen production. This study demonstrates that TGF-beta 1 induces alpha-SMA expression and collagen production in human lung fibroblasts via ERK1/2 activation, GSK-3 beta inhibition and nuclear beta-catenin translocation. The evidence that the silencing of beta-catenin by siRNAs was able to prevent the induction of alpha-SMA expression in TGF-beta 1-treated fibroblasts further supports the hypothesis of a contribution of the GSK-3 beta/beta-catenin pathway in the pathogenesis of idiopathic pulmonary fibrosis
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/5868
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