title: Negative Fgf8-Bmp2 feed-back is regulated by miR-130 during early cardiac specification.
abstract: It is known that secreted proteins from the anterior lateral endoderm, FGF8 and BMP2, are involved in mesodermal cardiac differentiation, which determines the first cardiac field, defined by the expression of the earliest specific cardiac markers Nkx-2.5 and Gata4. However, the molecular mechanisms responsible for early cardiac development still remain unclear. At present, microRNAs represent a novel layer of complexity in the regulatory networks controlling gene expression during cardiovascular development. This paper aims to study the role of miR130 during early cardiac specification. Our model is focused on developing chick at gastrula stages. In order to identify those regulatory factors which are involved in cardiac specification, we conducted gain- and loss-of-function experiments in precardiac cells by administration of Fgf8, Bmp2 and miR130, through in vitro electroporation technique and soaked beads application. Embryos were subjected to in situ hybridization, immunohistochemistry and qPCR procedures. Our results reveal that Fgf8 suppresses, while Bmp2 induces, the expression of Nkx-2.5 and Gata4. They also show that Fgf8 suppresses Bmp2, and vice versa. Additionally, we observed that Bmp2 regulates miR-130 -a putative microRNA that targets Erk1/2 (Mapk1) 3'UTR, recognizing its expression in precardiac cells which overlap with Erk1/2 pattern. Finally, we evidence that miR-130 is capable to inhibit Erk1/2 and Fgf8, resulting in an increase of Bmp2, Nkx-2.5 and Gata4. Our data present miR-130 as a necessary linkage in the control of Fgf8 signaling, mediated by Bmp2, establishing a negative feed-back loop responsible to achieve early cardiac specification.
authors.affiliation: Human Anatomy and Embryology, Faculty of Medicine, University of Extremadura, 06006 Badajoz, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Lopez-Sanchez
authors.affiliation: Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, CU Las Lagunillas B3-362, 23071 Jaén, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Franco
authors.affiliation: Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, CU Las Lagunillas B3-362, 23071 Jaén, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Bonet
authors.affiliation: Pharmacy Services, Minimally Invasive Surgery Centre, Cáceres, Spain.
authors.forename: Virginio
authors.initials: V
authors.lastname: Garcia-Lopez
authors.affiliation: Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, CU Las Lagunillas B3-362, 23071 Jaén, Spain.
authors.forename: Amelia
authors.initials: A
authors.lastname: Aranega
authors.affiliation: Human Anatomy and Embryology, Faculty of Medicine, University of Extremadura, 06006 Badajoz, Spain. Electronic address: virginio@unex.es.
authors.forename: Virginio
authors.initials: V
authors.lastname: Garcia-Martinez
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002642:Chick Embryo; D018274:Electroporation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors; D051524:Fibroblast Growth Factor 8 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050991:GATA4 Transcription Factor / Q000096:biosynthesis; D005775:Gastrula / Q000196:embryology*; D006321:Heart / Q000196:embryology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D035683:MicroRNAs / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis
chemical_list: D055396:Bone Morphogenetic Protein 2; D050991:GATA4 Transcription Factor; D035683:MicroRNAs; D014157:Transcription Factors; D051524:Fibroblast Growth Factor 8; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Bmp2; Cardiac specification; Electroporation; Fgf8; MiR-130