title: In vivo repopulating activity emerges at the onset of hematopoietic specification during embryonic stem cell differentiation.
abstract: The generation of in vivo repopulating hematopoietic cells from in vitro differentiating embryonic stem cells has remained a long-standing challenge. To date, hematopoietic engraftment has mostly been achieved through the enforced expression of ectopic transcription factors. Here, we describe serum-free culture conditions that allow the generation of in vivo repopulating hematopoietic cells in the absence of ectopically expressed factors. We show that repopulating activity arises immediately upon the commitment of mesodermal precursors to the blood program, within the first wave of hematopoietic specification. We establish that the formation of these progenitors is extremely transient and exquisitely sensitive to the cytokine milieu. Our findings define the precise differentiating stage at which hematopoietic repopulating activity first appears in vitro, and suggest that during embryonic stem cell differentiation, all hematopoietic programs are unraveled simultaneously from the mesoderm in the absence of cues that restrict the coordinated emergence of each lineage as is normally observed during embryogenesis.
authors: Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK.
authors: Stella
authors: S
authors: Pearson
authors: Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK.
authors: Sara
authors: S
authors: Cuvertino
authors: Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK.
authors: Maud
authors: M
authors: Fleury
authors: Stem Cell Biology Group, Cancer Research UK Manchester Institute, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. Electronic address: georges.lacaud@cruk.manchester.ac.uk.
authors: Georges
authors: G
authors: Lacaud
authors: Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. Electronic address: valerie.kouskoff@cruk.manchester.ac.uk.
authors: Valerie
authors: V
authors: Kouskoff
mesh_terms: D028341:Activins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D016207:Cytokines / Q000494:pharmacology; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005346:Fibroblast Growth Factors; D006410:Hematopoiesis / Q000187:drug effects / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D016130:Immunophenotyping; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010641:Phenotype; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D033581:Stem Cell Transplantation; D042442:Vascular Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D055415:Bone Morphogenetic Protein 4; D016207:Cytokines; D040201:Platelet Membrane Glycoprotein IIb; D042442:Vascular Endothelial Growth Factors; C422405:activin A; D028341:Activins; D005346:Fibroblast Growth Factors; D019009:Proto-Oncogene Proteins c-kit