title: Human ESC-derived hemogenic endothelial cells undergo distinct waves of endothelial to hematopoietic transition.
abstract: Several studies have demonstrated that hematopoietic cells originate from endotheliumin early development; however, the phenotypic progression of progenitor cells during human embryonic hemogenesis is not well described. Here, we define the developmental hierarchy among intermediate populations of hematopoietic progenitor cells (HPCs) derived from human embryonic stem cells (hESCs). We genetically modified hESCs to specifically demarcate acquisition of vascular (VE-cadherin) and hematopoietic (CD41a) cell fate and used this dual-reporting transgenic hESC line to observe endothelial to hematopoietic transition by real-time confocal microscopy. Live imaging and clonal analyses revealed a temporal bias in commitment of HPCs that recapitulates discrete waves of lineage differentiation noted during mammalian hemogenesis. Specifically, HPCs isolated at later time points showed reduced capacity to form erythroid/ megakaryocytic cells and exhibited a tendency toward myeloid fate that was enabled by expression of the Notch ligand Dll4 on hESC-derived vascular feeder cells. These data provide a framework for defining HPC lineage potential, elucidate a molecular contribution from the vascular niche in promoting hematopoietic lineage progression, and distinguish unique subpopulations of hemogenic endothelium during hESC differentiation.
  
  
  CONCLUSIONS
  Live imaging of endothelial to hematopoietic conversion identifies distinct subpopulations of hESC-derived hemogenic endothelium. Expression of the Notch ligand DII4 on vascular ECs drives induction of myeloid fate from hESC-derived hematopoietic progenitors.
authors.affiliation: Department of Genetic Medicine, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA.
authors.forename: Shahin
authors.initials: S
authors.lastname: Rafii
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Kloss
authors.forename: Jason M
authors.initials: JM
authors.lastname: Butler
authors.forename: Michael
authors.initials: M
authors.lastname: Ginsberg
authors.forename: Eric
authors.initials: E
authors.lastname: Gars
authors.forename: Raphael
authors.initials: R
authors.lastname: Lis
authors.forename: Qiansheng
authors.initials: Q
authors.lastname: Zhan
authors.forename: Pavle
authors.initials: P
authors.lastname: Josipovic
authors.forename: Bi-Sen
authors.initials: BS
authors.lastname: Ding
authors.forename: Jenny
authors.initials: J
authors.lastname: Xiang
authors.forename: Olivier
authors.initials: O
authors.lastname: Elemento
authors.forename: Nikica
authors.initials: N
authors.lastname: Zaninovic
authors.forename: Zev
authors.initials: Z
authors.lastname: Rosenwaks
authors.forename: Michel
authors.initials: M
authors.lastname: Sadelain
authors.forename: Jeremie A
authors.initials: JA
authors.lastname: Rafii
authors.forename: Daylon
authors.initials: D
authors.lastname: James
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D015820:Cadherins / Q000096:biosynthesis / Q000235:genetics; D002454:Cell Differentiation; D018920:Coculture Techniques; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D061252:Feeder Cells; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D040201:Platelet Membrane Glycoprotein IIb / Q000096:biosynthesis / Q000235:genetics; D014161:Transduction, Genetic; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D040201:Platelet Membrane Glycoprotein IIb; D000099152:Cadherin 5