title: NKX2-1 activation by SMAD2 signaling after definitive endoderm differentiation in human embryonic stem cell.
abstract: Expression of NKX2-1 is required to specify definitive endoderm to respiratory endoderm. However, the transcriptional regulation of NKX2-1 is not fully understood. Here we demonstrate that aside from specifying undifferentiated human embryonic stem cell (hESC) to definitive endoderm, high concentrations of Activin-A are also necessary and sufficient to induce hESC-derived definitive endodermal progeny to a FOXA2/NKX2-1/GATA6/PAX9 positive respiratory epithelial fate. Activin-A directly mediates the induction of NKX2-1 by interacting with ALK4, leading to phosphorylation of SMAD2, which binds directly to the NKX2-1 promoter and activates its expression. Activin-A can be replaced by GDF11 but not transforming growth factor β1. Addition of Wnt3a, SHH, FGF2, or BMP4 failed to induce NKX2-1. These results suggest that direct binding of Activin-A-responsive SMAD2 to the NKX2-1 promoter plays essential role during respiratory endoderm specification.
authors.affiliation: Interdepartmentaal Stamcelinstituut, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Kristel
authors.initials: K
authors.lastname: Eggermont
authors.forename: Veerle
authors.initials: V
authors.lastname: Vanslembrouck
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Verfaillie
mesh_terms: D028341:Activins / Q000502:physiology; D001665:Binding Sites; D019485:Bone Morphogenetic Proteins / Q000502:physiology; D002454:Cell Differentiation; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000502:physiology*; D004707:Endoderm / Q000166:cytology*; D005786:Gene Expression Regulation; D055412:Growth Differentiation Factors / Q000502:physiology; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D012137:Respiratory System / Q000166:cytology; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism*; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins; C492266:GDF11 protein, human; D055412:Growth Differentiation Factors; D009687:Nuclear Proteins; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; C422405:activin A; D028341:Activins