title: Hematopoietic differentiation of human embryonic stem cells progresses through sequential hematoendothelial, primitive, and definitive stages resembling human yolk sac development.
abstract: We elucidate the cellular and molecular kinetics of the stepwise differentiation of human embryonic stem cells (hESCs) to primitive and definitive erythromyelopoiesis from human embryoid bodies (hEBs) in serum-free clonogenic assays. Hematopoiesis initiates from CD45 hEB cells with emergence of semiadherent mesodermal-hematoendothelial (MHE) colonies that can generate endothelium and form organized, yolk sac-like structures that secondarily generate multipotent primitive hematopoietic stem progenitor cells (HSPCs), erythroblasts, and CD13+CD45+ macrophages. A first wave of hematopoiesis follows MHE colony emergence and is predominated by primitive erythropoiesis characterized by a brilliant red hemoglobinization, CD71/CD325a (glycophorin A) expression, and exclusively embryonic/fetal hemoglobin expression. A second wave of definitive-type erythroid burst-forming units (BFU-e's), erythroid colony-forming units (CFU-e's), granulocyte-macrophage colony-forming cells (GM-CFCs), and multilineage CFCs follows next from hEB progenitors. These stages of hematopoiesis proceed spontaneously from hEB-derived cells without requirement for supplemental growth factors during hEB differentiation. Gene expression analysis of differentiating hEBs revealed that initiation of hematopoiesis correlated with increased levels of SCL/TAL1, GATA1, GATA2, CD34, CD31, and the homeobox gene-regulating factor CDX4 These data indicate that hematopoietic differentiation of hESCs models the earliest events of embryonic and definitive hematopoiesis in a manner resembling human yolk sac development, thus providing a valuable tool for dissecting the earliest events in human HSPC genesis.
authors.affiliation: Division of Immunology and Hematopoiesis, Sidney Kimmel comprehensive Cancer Center at John Hokins, The John Hopkins School of Medicine, Baltimore, MD, USA. ezambid1@jhmi.edu
authors.forename: Elias T
authors.initials: ET
authors.lastname: Zambidis
authors.forename: Bruno
authors.initials: B
authors.lastname: Peault
authors.forename: Tea Soon
authors.initials: TS
authors.lastname: Park
authors.forename: Fred
authors.initials: F
authors.lastname: Bunz
authors.forename: Curt I
authors.initials: CI
authors.lastname: Civin
mesh_terms: D015703:Antigens, CD / Q000235:genetics; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D004727:Endothelium / Q000166:cytology* / Q000196:embryology; D004920:Erythropoiesis; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis; D006801:Humans; D017493:Leukocyte Common Antigens; D038042:Myelopoiesis; D013234:Stem Cells / Q000166:cytology*; D014157:Transcription Factors / Q000235:genetics; D015017:Yolk Sac / Q000254:growth & development
chemical_list: D015703:Antigens, CD; D014157:Transcription Factors; D017493:Leukocyte Common Antigens