Clonal and systemic analysis of long-term hematopoiesis in the mouse.

Abstract

We have analyzed the temporal in vivo fate of 142 individual stem cell clones in 63 reconstituted mice. Longterm sequential analyses of the four major peripheral blood lineages, obtained from animals engrafted with genetically marked stem cells, indicate that developmental behavior is primarily a function of time. As such, the first 4-6 months post-engraftment is characterized by frequent fluctuations in stem cell proliferation and differentiation behavior. Gradually, a stable hematopoietic system emerges, dominated by a small number of totipotent clones. We demonstrate that single stem cell clones are sufficient to maintain hematopoiesis over the lifetime of an animal and suggest that mono-or oligoclonality may be a hallmark of long-term reconstituted systems. A model is proposed, wherein lineage-restricted differentiation and dramatic clonal flux are consequences of mechanisms acting on an expanding pool of totipotent cells and are not indicative of intrinsically distinct stem cell classes.

Epigenetic Memory Underlies Cell-Autonomous Heterogeneous Behavior of Hematopoietic Stem Cells

“…These include cells that have distinctive behaviors in terms of cell production and lineage bias (Dykstra et al, 2007;Picelli et al, 2013). Hematopoietic stem cells have been demonstrated to exhibit bias toward myeloid, lymphoid, or megakaryocytic lineage upon transplantation of single cells (Dykstra et al, 2007(Dykstra et al, , 2011Morita et al, 2010), on ex vivo barcoding and transplantation of populations (Aiuti et al, 2013;Gerrits et al, 2010;Jordan and Lemischka, 1990;Lemischka, 1993;Lemischka et al, 1986;Lu et al, 2011;Mazurier et al, 2004;Shi et al, 2002;Snodgrass and Keller, 1987), or by retrotransposon tagging of endogenous cells (Sun et al, 2014b). Further, single-cell transplant data have been coupled with single-cell gene expression analysis on different cells to resolve subpopulations with corresponding gene expression and repopulation potential (Wilson et al, 2015).…”

CD34+ cells mobilized by cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) are functionally different from CD34+ cells mobilized by G-CSF

“…Murine studies in which isoenzyme analysis and retroviral gene marking of hematopoietic cells have been used to track the fate of stem cells support the existence of distinct subsets of stem cells which may be responsible for short-term and long-term engraftment after stem cell transplantation. 35,36 In human subjects there is no clear evidence for the separation of distinct subsets of cells with differing repopulating potentials. A functional heterogeneity of transplantation potential of human stem cells can be argued from recipients of mobilized peripheral blood transplants who have a rapid hematopoietic reconstitution suggesting either that mobilized peripheral blood is enriched for short-term repopulating stem cells or a substantial contribution of CFU-GM in the early phase of engraftment.…”

Comparison of Hematopoietic Activities of Human Bone Marrow and Umbilical Cord Blood CD34 Positive and Negative Cells

“…However, in vitro colony-forming cells are a heterogeneous population including both lineage-uncommitted and -committed hematopoietic progenitors. Furthermore, these colonyforming cells appear to be biologically distinct from more primitive HSCs, with long-term marrow-repopulating ability as indicated in mouse studies [14][15][16][17]. Although enriched human BM as well as CB CD34 + cells have already been used for clinical transplantation to marrow-ablated patients, it has not yet been concluded whether CD34 + cells in CB and BM are equally capable of long-term marrow reconstitution.…”