title: Fibroblast growth factor receptor-1 is essential for in vitro cardiomyocyte development.
abstract: Fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling plays a crucial role in mesoderm formation and patterning. Heartless mutant studies in Drosophila suggest that FGFR1, among the different FGFRs, may play a role in cardiogenesis. However, fgfr1-/- mice die during gastrulation before heart formation. To establish the contribution of FGFR1 in cardiac development, we investigated the capacity of murine fgfr1+/- and fgfr1-/- embryonic stem (ES) cells to differentiate to cardiomyocytes in vitro. Clusters of pulsating cardiomyocytes were observed in >90% of 3-dimensional embryoid bodies (EBs) originated from fgfr1+/- ES cells at day 9 to 10 of differentiation. In contrast, 10% or less of fgfr1-/- EBs showed beating foci at day 16. Accordingly, fgfr1-/- EBs were characterized by impaired expression of early cardiac transcription factors Nkx2.5 and d-Hand and of late structural cardiac genes myosin heavy chain (MHC)-alpha, MHC-beta, and ventricular myosin light chain. Homozygous fgfr1 mutation resulted also in alterations of the expression of mesoderm-related early genes, including nodal, BMP2, BMP4, T(bra), and sonic hedgehog. Nevertheless, fgfr1+/- and fgfr1-/- EBs similarly express cardiogenic precursor, endothelial, hematopoietic, and skeletal muscle markers, indicating that fgfr1-null mutation exerts a selective effect on cardiomyocyte development in differentiating ES cells. Accordingly, inhibitors of FGFR signaling, including the FGFR1 tyrosine kinase inhibitor SU 5402, the MEK1/2 inhibitor U0126, and the protein kinase C inhibitor GF109 all prevented cardiomyocyte differentiation in fgfr1+/- EBs without affecting the expression of the hematopoietic/endothelial marker flk-1. In conclusion, the data point to a nonredundant role for FGFR1-mediated signaling in cardiomyocyte development.
authors.affiliation: Unit of General Pathology and Immunology, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Dell'Era
authors.forename: Roberto
authors.initials: R
authors.lastname: Ronca
authors.forename: Laura
authors.initials: L
authors.lastname: Coco
authors.forename: Stefania
authors.initials: S
authors.lastname: Nicoli
authors.forename: Marco
authors.initials: M
authors.lastname: Metra
authors.forename: Marco
authors.initials: M
authors.lastname: Presta
mesh_terms: D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000502:physiology; D015870:Gene Expression; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000235:genetics; D009570:Nitriles / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011758:Pyrroles / Q000494:pharmacology; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors; D029867:Xenopus Proteins / Q000235:genetics
chemical_list: D002070:Butadienes; D004791:Enzyme Inhibitors; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C095552:NKX2-5 protein, human; D009570:Nitriles; C484469:Nkx2-5 protein, mouse; D011758:Pyrroles; D017468:Receptors, Fibroblast Growth Factor; C105686:SU 5402; D014157:Transcription Factors; C113580:U 0126; D029867:Xenopus Proteins; D004815:Epidermal Growth Factor; C496349:Fgfr1 protein, mouse; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D020929:Mitogen-Activated Protein Kinase Kinases; D018995:Myosin Heavy Chains; D013755:Tetradecanoylphorbol Acetate