title: Embryonic stem cell-derived CD166+ precursors develop into fully functional sinoatrial-like cells.
abstract: BACKGROUND
  A cell-based biological pacemaker is based on the differentiation of stem cells and the selection of a population displaying the molecular and functional properties of native sinoatrial node (SAN) cardiomyocytes. So far, such selection has been hampered by the lack of proper markers. CD166 is specifically but transiently expressed in the mouse heart tube and sinus venosus, the prospective SAN.
  
  
  OBJECTIVE
  We have explored the possibility of using CD166 expression for isolating SAN progenitors from differentiating embryonic stem cells.
  
  
  RESULTS
  We found that in embryonic day 10.5 mouse hearts, CD166 and HCN4, markers of the pacemaker tissue, are coexpressed. Sorting embryonic stem cells for CD166 expression at differentiation day 8 selects a population of pacemaker precursors. CD166+ cells express high levels of genes involved in SAN development (Tbx18, Tbx3, Isl-1, Shox2) and function (Cx30.2, HCN4, HCN1, CaV1.3) and low levels of ventricular genes (Cx43, Kv4.2, HCN2, Nkx2.5). In culture, CD166+ cells form an autorhythmic syncytium composed of cells morphologically similar to and with the electrophysiological properties of murine SAN myocytes. Isoproterenol increases (+57%) and acetylcholine decreases (-23%) the beating rate of CD166-selected cells, which express the β-adrenergic and muscarinic receptors. In cocultures, CD166-selected cells are able to pace neonatal ventricular myocytes at a rate faster than their own. Furthermore, CD166+ cells have lost pluripotency genes and do not form teratomas in vivo.
  
  
  CONCLUSIONS
  We demonstrated for the first time the isolation of a nonteratogenic population of cardiac precursors able to mature and form a fully functional SAN-like tissue.
authors.affiliation: Department of Biosciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Scavone
authors.forename: Daniela
authors.initials: D
authors.lastname: Capilupo
authors.forename: Nausicaa
authors.initials: N
authors.lastname: Mazzocchi
authors.forename: Alessia
authors.initials: A
authors.lastname: Crespi
authors.forename: Stefano
authors.initials: S
authors.lastname: Zoia
authors.forename: Giulia
authors.initials: G
authors.lastname: Campostrini
authors.forename: Annalisa
authors.initials: A
authors.lastname: Bucchi
authors.forename: Raffaella
authors.initials: R
authors.lastname: Milanesi
authors.forename: Mirko
authors.initials: M
authors.lastname: Baruscotti
authors.forename: Sara
authors.initials: S
authors.lastname: Benedetti
authors.forename: Stefania
authors.initials: S
authors.lastname: Antonini
authors.forename: Graziella
authors.initials: G
authors.lastname: Messina
authors.forename: Dario
authors.initials: D
authors.lastname: DiFrancesco
authors.forename: Andrea
authors.initials: A
authors.lastname: Barbuti
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D020410:Activated-Leukocyte Cell Adhesion Molecule / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D018920:Coculture Techniques; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D012849:Sinoatrial Node / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D020410:Activated-Leukocyte Cell Adhesion Molecule; D015415:Biomarkers; D002316:Cardiotonic Agents; C578706:Hcn4 protein, mouse; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D007545:Isoproterenol; D000109:Acetylcholine
keywords: HCN channels; cardiac progenitor cells; embryonic stem cells; pacemaker; sinoatrial node