title: Signaling pathways controlling second heart field development.
abstract: Insight into the mechanisms underlying congenital heart defects and the use of stem cells for cardiac repair are major research goals in cardiovascular biology. In the early embryo, progenitor cells in pharyngeal mesoderm contribute to the rapid growth of the heart tube during looping morphogenesis. These progenitor cells constitute the second heart field (SHF) and were first identified in 2001. Direct or indirect perturbation of SHF addition to the heart results in congenital heart defects, including arterial pole alignment defects. Over the last 3 years, a number of studies have identified key intercellular signaling pathways that control the proliferation and deployment of SHF progenitor cells. Here, we review data concerning Wnt, fibroblast growth factor, bone morphogenetic protein, Hedgehog, and retinoic acid signaling that have begun to identify the ligand sources and responding cell types controlling SHF development. These studies have revealed the importance of signals from pharyngeal mesoderm itself, as well as critical inputs from adjacent pharyngeal epithelia and neural crest cells. Proliferation is emerging as a central checkpoint in the regulation of SHF development. Together, these studies contribute to defining the niche of cardiac progenitor cells in the early embryo, and we discuss the implications of these findings for the regulation of resident stem cell populations in the fetal and postnatal heart. Characterization of signals that maintain, expand, and regulate the differentiation of cardiac progenitor cells is essential for understanding both the etiology of congenital heart defects and the biomedical application of stem cell populations for cardiac repair.
authors.affiliation: Developmental Biology Institute of Marseilles-Luminy, UMR 6216 Centre National de la Recherche Scientifique-Université de laMéditerranée, Campus de Luminy, Marseille, France.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rochais
authors.forename: Karim
authors.initials: K
authors.lastname: Mesbah
authors.forename: Robert G
authors.initials: RG
authors.lastname: Kelly
mesh_terms: D000818:Animals; D019898:Autocrine Communication; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D001934:Branchial Region; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D053595:Embryonic Stem Cells / Q000378:metabolism*; D004707:Endoderm / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006321:Heart / Q000196:embryology*; D006330:Heart Defects, Congenital / Q000196:embryology / Q000378:metabolism* / Q000601:surgery; D053823:Hedgehog Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D060850:LIM-Homeodomain Proteins; D008648:Mesoderm / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009432:Neural Crest / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000378:metabolism*; D015398:Signal Transduction; D033581:Stem Cell Transplantation; D014157:Transcription Factors; D014212:Tretinoin / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D051176:beta Catenin; C063843:insulin gene enhancer binding protein Isl-1; D014212:Tretinoin; D005346:Fibroblast Growth Factors