title: TGF-β1 induces tissue factor expression in human lung fibroblasts in a PI3K/JNK/Akt-dependent and AP-1-dependent manner.
abstract: The disturbance of hemostatic balance, associated with increased tissue factor (TF) expression and activity, occurs in the lungs of patients with idiopathic pulmonary fibrosis (IPF). However, the molecular mechanisms responsible for the regulation of TF expression under profibrotic conditions have not been assessed. We found that transforming growth factor-β1 (TGF-β1) markedly enhanced TF expression in primary human lung fibroblasts (HLFs), whereas platelet-derived growth factor (PDGF)-BB and IGF (insulin-like growth factor)-1 showed only a moderate effect, and PDGB-CC exerted no effect. TGF-β1-induced TF expression correlated with its elevated cell-surface activity, it required de novo gene transcription and protein synthesis, and it was dependent on JNK and Akt activity, because pharmacological inhibition or the knockdown of the previously mentioned kinases prevented TF synthesis. Exposure of HLFs to TGF-β1 activated JNK in a PI3K-dependent manner and induced Akt phosphorylation at threonine 308 and serine 473, but did not change the phosphorylation status of threonine 450. Akt phosphorylation at serine 473 correlated with JNK activity, and co-immunoprecipitation studies revealed a direct interaction between JNK and Akt. Furthermore, TGF-β1-induced TF expression required the recruitment of c-Fos and JunD into a heterodimeric activator protein (AP)-1 complex. Moreover, strong immunoreactivity for phosphorylated Akt and JNK as well as c-Fos and JunD was observed in fibroblasts and myofibroblasts in IPF lungs. In conclusion, PI3K/JNK/Akt and AP-1 synergize to induce TF expression in HLFs after TGF-β1 challenge. Our findings provide new insights into the molecular mechanisms responsible for the regulation of TF expression, and open new perspectives on the treatment of pulmonary fibrosis and other diseases characterized by the inappropriate expression of this cell-surface receptor.
authors: Department of Biochemistry, Faculty of Medicine, University of Giessen Lung Center, Friedrichstrasse 24, 35392 Giessen, Germany. malgorzata.wygrecka@innere.med.uni-giessen.de
authors: Malgorzata
authors: M
authors: Wygrecka
authors: Dariusz
authors: D
authors: Zakrzewicz
authors: Brigitte
authors: B
authors: Taborski
authors: Miroslava
authors: M
authors: Didiasova
authors: Grazyna
authors: G
authors: Kwapiszewska
authors: Klaus T
authors: KT
authors: Preissner
authors: Philipp
authors: P
authors: Markart
mesh_terms: D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation; D006207:Half-Life; D054990:Idiopathic Pulmonary Fibrosis / Q000378:metabolism / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008168:Lung / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D061251:Primary Cell Culture; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D020871:RNA Stability; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D015398:Signal Transduction; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D053773:Transforming Growth Factor beta1 / Q000502:physiology*
chemical_list: D048031:JNK Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta; D013925:Thromboplastin; D018808:Transcription Factor AP-1; D053773:Transforming Growth Factor beta1; C559371:JunD protein, human