title: Col1A1 production and apoptotic resistance in TGF-β1-induced epithelial-to-mesenchymal transition-like phenotype of 603B cells.
abstract: Recent studies have suggested that proliferating cholangiocytes have an important role in the induction of fibrosis, either directly via epithelial-to-mesenchymal transition (EMT), or indirectly via activation of other liver cell types. Transforming growth factor beta 1 (TGF-β1), a critical fibrotic cytokine for hepatic fibrosis, is a potent EMT inducer. This study aimed to clarify the potential contributions of TGF-β1-induced EMT-like cholangiocyte phenotype to collagen production and cell survival of cholangiocytes in vitro. Mouse cholangiocytes (603B cells) were treated with TGF-β1 and EMT-like phenotype alterations were monitored by morphological changes and expression of EMT-associated genes. Alterations in Col1A1 gene, Col1A1-associated miR-29s, and pro-apoptotic genes were measured in TGF-β1-treated 603B cells. Snail1 knockdown was achieved using shRNA to evaluate the contribution of EMT-associated changes to Col1A1 production and cell survival. We found TGF-β1 treatment induced partial EMT-like phenotype transition in 603B cells in a Snail1-dependent manner. TGF-β1 also stimulated collagen α1(I) expression in 603B cells. However, this induction was not parallel to the EMT-like alterations and independent of Snail1 or miR-29 expression. Cells undergoing EMT-like changes showed a modest down-regulation of multiple pro-apoptotic genes and displayed resistance to TNF-α-induced apoptosis. TGF-β1-induced apoptosis resistance was attenuated in Snail1 knockdown 603B cells. TGF-β1-induced Col1A1 production seems to be independent of EMT-like transition and miR-29 expression. Nevertheless, TGF-β1-induced EMT may contribute to the increased survival capacity of cholangiocytes via modulating the expression of pro-apoptotic genes.
authors.affiliation: Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Alex N
authors.initials: AN
authors.lastname: Eischeid
authors.forename: Xian-Ming
authors.initials: XM
authors.lastname: Chen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D001652:Bile Ducts / Q000166:cytology*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival; D024042:Collagen Type I / Q000096:biosynthesis*; D000090602:Collagen Type I, alpha 1 Chain; D017931:DNA Primers / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D055785:Gene Knockdown Techniques; D066298:In Vitro Techniques; D008156:Luciferases; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011419:Propidium; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D017931:DNA Primers; C547014:MIRN29 microRNA, mouse; D035683:MicroRNAs; C000604429:Snai1 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D053773:Transforming Growth Factor beta1; D011419:Propidium; D008156:Luciferases