title: Kinase inhibitors fail to induce mesenchymal-epithelial transition in fibroblasts from fibrotic lung tissue.
abstract: Epithelial-mesenchymal transition (EMT) has been considered to be involved in idiopathic pulmonary fibrosis (IPF). However, the EMT process in vivo is much more complex and controversial. Studies regarding the opposite process, mesenchymal-epithelial transition (MET) in fibroblasts, are limited. Therefore, the aim of this study was to verify the involvement of the transforming growth factor (TGF)-β1-dependent EMT network in the process of pulmonary fibrosis and to explore the possibility of MET. Fibrotic lung tissues were obtained from patients with IPF with histological evidence of usual interstitial pneumonia at the time of surgical lung biopsy. For the controls, histologically normal lung tissues were obtained from patients with primary spontaneous pneumothorax at the time of thoracoscopy with stapling of any air leaks. Real-time RT-PCR and western blot analysis revealed that the mRNA and protein levels of TGF-β1, TGF-β1 receptor type I/II/III (TβRI/II/III), Smad2/3/4 and Snail1/2 were significantly upregulated in the fibrotic lung tissue. Inhibitors of various kinases implicated in EMT, including TGF-β1/Smad, Rho kinase (ROCK), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun NH-terminal kinase (JNK) were used to determine the MET potential in fibroblasts from fibrotic lung tissue. Western blot analysis or indirect immunofluorescence staining revealed that Smad inhibitor, as well as other kinase inhibitors failed to induce the MET process, determined by cellular morphology and protein markers. Our data suggest that the MET process may not be the exact reversal of EMT. In addition to using kinase inhibitors, other intervention measures should be used to explore the possibility of the MET process in fibroblasts from fibrotic lung tissue.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, P.R. China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Xu
authors.forename: Xuan
authors.initials: X
authors.lastname: Wan
authors.forename: Jing
authors.initials: J
authors.lastname: Geng
authors.forename: Fei
authors.initials: F
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Huaping
authors.initials: H
authors.lastname: Dai
mesh_terms: D000328:Adult; D001549:Benzamides / Q000494:pharmacology; D016022:Case-Control Studies; D018929:Cell Culture Techniques; D004149:Dioxoles / Q000494:pharmacology; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects* / Q000235:genetics; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000235:genetics / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008297:Male; D008875:Middle Aged; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011658:Pulmonary Fibrosis / Q000235:genetics / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D055815:Young Adult; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D004149:Dioxoles; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D054460:rho-Associated Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases