title: Hematopoietic stem cells develop in the absence of endothelial cadherin 5 expression.
abstract: Rare endothelial cells in the aorta-gonad-mesonephros (AGM) transition into hematopoietic stem cells (HSCs) during embryonic development. Lineage tracing experiments indicate that HSCs emerge from cadherin 5 (Cdh5; vascular endothelial-cadherin)(+) endothelial precursors, and isolated populations of Cdh5(+) cells from mouse embryos and embryonic stem cells can be differentiated into hematopoietic cells. Cdh5 has also been widely implicated as a marker of AGM-derived hemogenic endothelial cells. Because Cdh5(-/-) mice embryos die before the first HSCs emerge, it is unknown whether Cdh5 has a direct role in HSC emergence. Our previous genetic screen yielded malbec (mlb(bw306)), a zebrafish mutant for cdh5, with normal embryonic and definitive blood. Using time-lapse confocal imaging, parabiotic surgical pairing of zebrafish embryos, and blastula transplantation assays, we show that HSCs emerge, migrate, engraft, and differentiate in the absence of cdh5 expression. By tracing Cdh5(-/-)green fluorescent protein (GFP)(+/+) cells in chimeric mice, we demonstrated that Cdh5(-/-)GFP(+/+) HSCs emerging from embryonic day 10.5 and 11.5 (E10.5 and E11.5) AGM or derived from E13.5 fetal liver not only differentiate into hematopoietic colonies but also engraft and reconstitute multilineage adult blood. We also developed a conditional mouse Cdh5 knockout (Cdh5(flox/flox):Scl-Cre-ER(T)) and demonstrated that multipotent hematopoietic colonies form despite the absence of Cdh5. These data establish that Cdh5, a marker of hemogenic endothelium in the AGM, is dispensable for the transition of hemogenic endothelium to HSCs.
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA; Harvard Medical School, Boston, MA;
authors.forename: Heidi
authors.initials: H
authors.lastname: Anderson
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA;
authors.forename: Taylor C
authors.initials: TC
authors.lastname: Patch
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Pavankumar N G
authors.initials: PN
authors.lastname: Reddy
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Elliott J
authors.initials: EJ
authors.lastname: Hagedorn
authors.affiliation: Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kim
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA;
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Soltis
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Chen
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Owen J
authors.initials: OJ
authors.lastname: Tamplin
authors.affiliation: Max Planck Institute for Molecular Biomedicine, Münster, Germany;
authors.forename: Maike
authors.initials: M
authors.lastname: Frye
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Glenn A
authors.initials: GA
authors.lastname: MacLean
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA;
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hübner
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA; Harvard Stem Cell Institute, Cambridge, MA;
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Bauer
authors.affiliation: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA; and.
authors.forename: John P
authors.initials: JP
authors.lastname: Kanki
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA;
authors.forename: Guillaume
authors.initials: G
authors.lastname: Vogin
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA;
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Huston
authors.affiliation: Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Minh
authors.initials: M
authors.lastname: Nguyen
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA; Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA;
authors.forename: Barry H
authors.initials: BH
authors.lastname: Paw
authors.affiliation: Max Planck Institute for Molecular Biomedicine, Münster, Germany;
authors.forename: Dietmar
authors.initials: D
authors.lastname: Vestweber
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA; Harvard Stem Cell Institute, Cambridge, MA; Howard Hughes Medical Institute, Boston, MA.
authors.forename: Leonard I
authors.initials: LI
authors.lastname: Zon
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA; Harvard Stem Cell Institute, Cambridge, MA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA; and Howard Hughes Medical Institute, Boston, MA.
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Orkin
authors.affiliation: Harvard Medical School, Boston, MA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA; Harvard Stem Cell Institute, Cambridge, MA; Howard Hughes Medical Institute, Boston, MA.
authors.forename: George Q
authors.initials: GQ
authors.lastname: Daley
authors.affiliation: Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Boston, MA; Harvard Medical School, Boston, MA; Harvard Stem Cell Institute, Cambridge, MA;
authors.forename: Dhvanit I
authors.identifier: http://orcid.org/0000-0002-3173-2402
authors.initials: DI
authors.lastname: Shah
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage / Q000502:physiology; D018274:Electroporation; D004622:Embryo, Mammalian; D004625:Embryo, Nonmammalian; D005434:Flow Cytometry; D055018:Hemangioblasts / Q000166:cytology*; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007150:Immunohistochemistry; D008650:Mesonephros / Q000196:embryology; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D015027:Zebrafish; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D000099152:Cadherin 5