title: Individual stem cells with highly variable proliferation and self-renewal properties comprise the human hematopoietic stem cell compartment.
abstract: Hematopoiesis requires tight regulation of the hematopoietic stem cell (HSC) population; however, the dynamics of HSC use at steady state are uncertain. Over 3-7 months, we evaluated the repopulation and self-renewal of more than 600 individual human 'severe combined immunodeficiency mouse-repopulating cells' (SRCs), tracked on the basis of lentiviral integration sites, in serially transplanted immune-deficient mice, as well as of SRC daughter cells that migrated to different marrow locations in a single mouse. Our data demonstrate maintenance by self-renewing SRCs after an initial period of clonal instability, a result inconsistent with the clonal succession model. We found wide variation in proliferation kinetics and self-renewal among SRCs, as well as between SRC daughter cells that repopulated equivalently, suggesting that SRC fate is unpredictable before SRCs enter more rigid 'downstream' developmental programs.
authors.affiliation: Division of Cell and Molecular Biology, University Health Network, University of Toronto, Ontario M5G 1L7, Canada.
authors.forename: Joby L
authors.initials: JL
authors.lastname: McKenzie
authors.forename: Olga I
authors.initials: OI
authors.lastname: Gan
authors.forename: Monica
authors.initials: M
authors.lastname: Doedens
authors.forename: Jean C Y
authors.initials: JC
authors.lastname: Wang
authors.forename: John E
authors.initials: JE
authors.lastname: Dick
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000378:metabolism; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002999:Clone Cells; D005312:Fetal Blood / Q000166:cytology / Q000637:transplantation; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID
chemical_list: D018952:Antigens, CD34; D008562:Membrane Glycoproteins; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1