title: The cellular prion protein identifies bipotential cardiomyogenic progenitors.
abstract: BACKGROUND
  The paucity of specific surface markers for cardiomyocytes and their progenitors has impeded the development of embryonic or pluripotent stem cell-based transplantation therapy. Identification of relevant surface markers may also enhance our understanding of the mechanisms underlying differentiation.
  
  
  OBJECTIVE
  Here, we show that cellular prion protein (PrP) serves as an effective surface marker for isolating nascent cardiomyocytes as well as cardiomyogenic progenitors.
  
  
  RESULTS
  Embryonic stem (or embryo-derived) cells were analyzed using flow cytometry to detect surface expression of PrP and intracellular myosin heavy chain (Myhc) proteins. Sorted cells were then analyzed for their differentiation potential.
  
  
  CONCLUSIONS
  PrP+ cells from beating embryoid bodies (EBs) frequently included nascent Myhc+ cardiomyocytes. Cultured PrP+ cells further differentiated, giving rise to cardiac troponin I+ definitive cardiomyocytes with either an atrial or a ventricular identity. These cells were electrophysiologically functional and able to survive in vivo after transplantation. Combining PrP with a second marker, platelet-derived growth factor receptor (PDGFR)alpha, enabled us to identify an earlier cardiomyogenic population from prebeating EBs, the PrP+PDGFRalpha+ (PRa) cells. The Myhc- PRa cells expressed cardiac transcription factors, such as Nkx2.5, T-box transcription factor 5, and Isl1 (islet LIM homeobox 1), although they were not completely committed. In mouse embryos, PRa cells in cardiac crescent at the 1 to 2 somite stage were Myhc+, whereas they were Myhc- at headfold stages. PRa cells clonally expanded in methlycellulose cultures. Furthermore, single Myhc- PRa cell-derived colonies contained both cardiac and smooth muscle cells. Thus, PrP demarcates a population of bipotential cardiomyogenic progenitor cells that can differentiate into cardiac or smooth muscle cells.
authors.affiliation: Department of Bioscience, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hidaka
authors.forename: Manabu
authors.initials: M
authors.lastname: Shirai
authors.forename: Jong-Kook
authors.initials: JK
authors.lastname: Lee
authors.forename: Takanari
authors.initials: T
authors.lastname: Wakayama
authors.forename: Itsuo
authors.initials: I
authors.lastname: Kodama
authors.forename: Michael D
authors.initials: MD
authors.lastname: Schneider
authors.forename: Takayuki
authors.initials: T
authors.lastname: Morisaki
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis* / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics; D060850:LIM-Homeodomain Proteins; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000096:biosynthesis / Q000235:genetics; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D011328:Prions / Q000096:biosynthesis* / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000096:biosynthesis / Q000235:genetics; D019170:Somites / Q000166:cytology / Q000196:embryology; D020825:T-Box Domain Proteins / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D019210:Troponin I / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000943:Antigens, Differentiation; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; C484469:Nkx2-5 protein, mouse; D011328:Prions; D020825:T-Box Domain Proteins; C103172:T-box transcription factor 5; D014157:Transcription Factors; D019210:Troponin I; C063843:insulin gene enhancer binding protein Isl-1; D020796:Receptor, Platelet-Derived Growth Factor alpha; D018995:Myosin Heavy Chains