title: Medial HOXA genes demarcate haematopoietic stem cell fate during human development.
abstract: Pluripotent stem cells (PSCs) may provide a potential source of haematopoietic stem/progenitor cells (HSPCs) for transplantation; however, unknown molecular barriers prevent the self-renewal of PSC-HSPCs. Using two-step differentiation, human embryonic stem cells (hESCs) differentiated in vitro into multipotent haematopoietic cells that had the CD34(+)CD38(-/lo)CD90(+)CD45(+)GPI-80(+) fetal liver (FL) HSPC immunophenotype, but exhibited poor expansion potential and engraftment ability. Transcriptome analysis of immunophenotypic hESC-HSPCs revealed that, despite their molecular resemblance to FL-HSPCs, medial HOXA genes remained suppressed. Knockdown of HOXA7 disrupted FL-HSPC function and caused transcriptome dysregulation that resembled hESC-derived progenitors. Overexpression of medial HOXA genes prolonged FL-HSPC maintenance but was insufficient to confer self-renewal to hESC-HSPCs. Stimulation of retinoic acid signalling during endothelial-to-haematopoietic transition induced the HOXA cluster and other HSC/definitive haemogenic endothelium genes, and prolonged HSPC maintenance in culture. Thus, medial HOXA gene expression induced by retinoic acid signalling marks the establishment of the definitive HSPC fate and controls HSPC identity and function.
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.|Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Diana R
authors.initials: DR
authors.lastname: Dou
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Vincenzo
authors.identifier: 0000-0002-7937-1511
authors.initials: V
authors.lastname: Calvanese
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Sierra
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Nguyen
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Arazin
authors.initials: A
authors.lastname: Minasian
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Pamela
authors.initials: P
authors.lastname: Saarikoski
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Sasidharan
authors.affiliation: Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Ramirez
authors.affiliation: Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.|Department of Medicine, Division of Hematology-Oncology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Zack
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.|Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Gay M
authors.initials: GM
authors.lastname: Crooks
authors.affiliation: Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.|Department of Medicine, Division of Hematology-Oncology, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Galic
authors.affiliation: Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095, USA.|Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California 90095, USA.|Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Hanna K A
authors.initials: HK
authors.lastname: Mikkola
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage; D002478:Cells, Cultured; D020869:Gene Expression Profiling / Q000379:methods; D005801:Genes, Homeobox / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D039902:Multipotent Stem Cells / Q000166:cytology*; D059467:Transcriptome
chemical_list: D018952:Antigens, CD34; D018398:Homeodomain Proteins; C088144:HoxA protein; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human