title: Neuregulin/ErbB signaling regulates cardiac subtype specification in differentiating human embryonic stem cells.
abstract: BACKGROUND
  Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) exhibit either a "working" chamber or a nodal-like phenotype. To generate optimal hESC-CM preparations for eventual clinical application in cell-based therapies, we will need to control their differentiation into these specialized cardiac subtypes.
  
  
  OBJECTIVE
  To demonstrate intact neuregulin (NRG)-1β/ErbB signaling in hESC-CMs and test the hypothesis that this signaling pathway regulates cardiac subtype abundance in hESC-CM cultures.
  
  
  RESULTS
  All experiments used hESC-CM cultures generated using our recently reported directed differentiation protocol. To support subsequent action potential phenotyping approaches and provide a higher-throughput method of determining cardiac subtype, we first developed and validated a novel genetic label that identifies nodal-type hESC-CMs. Next, control hESC-CM preparations were compared to those differentiated in the presence of exogenous NRG-1β, an anti-NRG-1β neutralizing antibody, or the ErbB antagonist AG1478. We used 3 independent approaches to determine the ratio of cardiac subtypes in the resultant populations: direct action potential phenotyping under current-clamp, activation of the aforementioned genetic label, and subtype-specific marker expression by RT-PCR. Using all 3 end points, we found that inhibition of NRG-1β/ErbB signaling greatly enhanced the proportion of cells showing the nodal phenotype.
  
  
  CONCLUSIONS
  NRG-1β/ErbB signaling regulates the ratio of nodal- to working-type cells in differentiating hESC-CM cultures and presumably functions similarly during early human heart development. We speculate that, by manipulating NRG-1β/ErbB signaling, it will be possible to generate preparations of enriched working-type myocytes for infarct repair, or, conversely, nodal cells for potential use in a biological pacemaker.
authors.affiliation: Center for Cardiovascular Biology, Department of Pathology, University of Washington, Seattle, WA 98109, USA.
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Zhu
authors.forename: Yiheng
authors.initials: Y
authors.lastname: Xie
authors.forename: Kara White
authors.initials: KW
authors.lastname: Moyes
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Gold
authors.forename: Bardia
authors.initials: B
authors.lastname: Askari
authors.forename: Michael A
authors.initials: MA
authors.lastname: Laflamme
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism* / Q000502:physiology; D066246:ErbB Receptors / Q000502:physiology*; D006801:Humans; D051379:Mice; D032383:Myocytes, Cardiac / Q000145:classification / Q000166:cytology* / Q000378:metabolism*; D020890:Neuregulin-1 / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D012849:Sinoatrial Node / Q000166:cytology / Q000196:embryology / Q000378:metabolism
chemical_list: D020890:Neuregulin-1; C117467:neuregulin beta; C512478:EGFR protein, human; D066246:ErbB Receptors