Hematopoietic Stem Cell Purification Leads to Loss of a Stem Cell Population within the Lineage Positive Cellular Fraction

Abstract Background: Hematopoietic stem cells (HSCs) have tremendous self-renewal and differentiation capacity. The majority of murine hematopoietic stem cell studies have focused on rare purified populations of HSCs, conventionally described as negative for lineage-specific markers and positive for particular cell surface epitope profiles, including c-Kit, Sca-1, and CD150. However, our data indicate that such purifications lead to the loss of a significant population of actively cycling marrow cells with long-term multi-lineage stem cell potential. In the studies presented here, we tested the hypothesis that this discarded stem cell population lies, in part, within the lineage positive (Lin+) fraction of marrow. Methods: We flushed whole bone marrow (WBM) from B6.SJL mice and incubated it with allophycocyanin-tagged antibodies against erythroid (TER119), myeloid (CD11b, GR1), B-lymphoid (B220), or T-lymphoid (CD3, CD4, CD8) markers. Different doses of each specific Lin+ subset isolated by fluorescence activated cell sorting were competitively engrafted into lethally irradiated C57BL/6 host mice. At 1,3, and 6 months post-transplant, peripheral blood was analyzed for donor contribution to chimerism and lineage specificity. Results: Although typically considered to be without stem cell activity, we found that all Lin+ sub-fractions upon single sorting were able to contribute to marrow repopulation in competitive bone marrow transplants. For example, when lethally irradiated recipient mice received 3x105 C57BL/6J competitive whole bone marrow cells in combination with single-sorted GR1+ ± CD11b+ cells (2x106 cells/mouse), peripheral blood showed 15% donor chimerism at 6 months. Similarly, if single sorted CD3+ ±CD4+ ±CD8+ cells (70,000 cells/mouse), B220+ cells (1x106 cells/mouse), or Ter119+ cells (1x106 cells/mouse) were competitively engrafted with 3x105 C57BL/6 WBM cells, the donor Lin+ sub-fractions contributed to 2%, 15%, and 35% peripheral blood chimerism at 6 months post-transplant, respectively. This contribution was multi-lineage in all cases. When we performed double sorting of the Lin+ subsets, there was a dramatically reduced engraftment capacity between 1-6% donor chimerism for all subgroups. However, we do not think the loss of stem cell capacity with double sorting seen in these studies is due merely to the loss of classical hematopoietic stem cells (Lineage-/stem cell marker+). In our earlier studies, we showed that the total Lin+ population contains long-term multi-lineage engraftment capacity due almost entirely to actively cycling cells. Therefore, if the engraftment capacity within the single sorted Lin+ sub-fractions was due solely to the presence of classical HSCs lost with double sorting, the engraftment capacity found within the Lin+ compartment should be due only to quiescent cells in keeping with the cell cycle status of engrafting highly purified stem cells. Conclusions: Based on these data, we predict that a cycling population of stem cells exists within this single sorted, Lin+ enriched fraction discarded with conventional HSC purification. Future studies are ongoing to further characterize the subsets of Lin+ cells that both remain Lin+ and are found to be Lin- upon double sorting. We will analyze these populations for engraftment capacity, concomitant stem cell marker expression and cell cycle status, in order to fully characterize the total stem cell potential within whole bone marrow that is not included in the purified HSC populations. Disclosures No relevant conflicts of interest to declare.

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Detection of a Stem Cell Population with Hemangioblastic Characteristics in Primary Myelofibrosis (PMF),

Blood ◽

10.1182/blood.v118.21.3860.3860 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3860-3860

Author(s):

Ioanna N Trivai ◽

Thomas Stuebig ◽

Anita Badbaran ◽

Ursula Gehling ◽

Asterios Tsiftsoglou ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Peripheral Blood ◽

Primary Myelofibrosis ◽

Jak2v617f Mutation ◽

Cell Subpopulation ◽

Stem Cell Population ◽

Allele Burden

Abstract Abstract 3860 Primary myelofibrosis (PMF) comprises a myeloproliferative neoplasia accompanied by imbalance of various tissues of the mesoderm, let alone the hematopoietic tissue. Involvement of multiple hematopoietic lineages during disease progression suggests the clonality of myelofibrosis that can be attributed to an initial stem cell defect at the very early stage of the stem cell hierarchy. Hematopoietic and endothelial phenotypes of circulating multipotent stem cells in patient peripheral blood, along with the increased microvascular density in the bone marrow, leads to the hypothesis that the critical event in PMF involves malignant transformation of a stem cell with hemangioblastic potential. Former studies have provided functional evidence that activated JAK2 signalling in primitive human hematopoietic cells is sufficient to drive key processes involved in the pathogenesis of the disease. In this study, the functionality and differentiation potential of circulating primitive JAK2V617F+ stem cells from primary myelofibrosis patients is assessed. Primitive stem cells were isolated from peripheral blood of 25 patients. All patients participating in the study were diagnosed with primary myelofibrosis, have been untreated, and were found positive for JAK2V617F mutation. Isolated stem cells were analysed for purity and assessed for the expression of markers characteristic for the hemangioblast phenotype (CD34, CD133, CD45, VEGFR2, VE-Cadherin, E-Cadherin, CD31) with flow cytometry. Genomic DNA was isolated from various stem cell populations to determine the mutational status by PCR. Our results indicate that long term repopulating stem cells circulating in peripheral blood bear the JAK2V617F mutation. Hemangioblast resembling populations within the isolated prime stem cells were also found positive for the mutation. Long term repopulating stem cells bearing different allele burden for JAK2V617F mutation from PMF patient peripheral blood were expanded for up to 4 months. Various colonies formed after seeding in semisolid media were characterised by morphological features (CFU-GEMM, CFU-GM, CFU-E, CFU-M, CFU-Endo) and expressing genes by quantitative PCR. Moreover, allele burden determination for various progenitors of both hematopoietic and endothelial lineages was performed. JAK2V617F allele burden varied within individual progeny phenotypes, indicating the acquisition of the mutation that boosts the outgrowth of the malignant clone within the hemangioblast compartment of the bone marrow. Endothelial and macrophage progenitors appear heterozygotic while all rest progenitors of various hematopoietic lineages can be either heterozygotic or homozygotic. This indicates high genomic instability of the JAK2V617F+ malignant clone as it is driven into hematopoietic differentiation. Our results indicate the existence of a malignant clone with hemangioblast phenotype in PMF which can differentiate into hematopoietic and/or endothelial progenitors in vitro. Our experiments shed light to the pathogenesis of PMF by characterising the potential of the defective stem cell subpopulation responsible for the disease. Disclosures: No relevant conflicts of interest to declare.

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Defining Engraftment Potential within the Lineage Positive Population in Murine Marrow

Blood ◽

10.1182/blood.v124.21.4303.4303 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4303-4303

Author(s):

Laura R. Goldberg ◽

Mark S Dooner ◽

Yanhui Deng ◽

Elaine Papa ◽

Mandy Pereira ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Stem Cell Marker ◽

Stem Cell Population ◽

Stem Cell Markers ◽

Cell Marker ◽

Cell Potential ◽

Hematopoietic Stem ◽

Cell Markers ◽

Donor Cells

Abstract The study of highly purified hematopoietic stem cells (HSCs) has dominated the field of hematopoietic stem cell biology. It is widely believed that the true stem cell population lies within the Lineage negative (Lin-) population, further sub-fractionated using positive and negative selection for surface markers such as c-Kit, Sca-1, CD150, CD41, CD48, and CD34. It is research on these highly purified subsets of HSCs that forms the foundation for almost all our knowledge of HSCs, and has led to the dogma that marrow stem cells are quiescent with a stable phenotype and therefore can be purified to near homogeneity. In contrast, we have shown that a large percentage of long-term multi-lineage marrow repopulating cells in whole bone marrow (WBM) are actively cycling, that these cycling stem cells are lost during conventional HSC isolation, and that they can be found, in part, within the discarded Lineage positive (Lin+) population. Here we present data further characterizing the stem cell potential in the Lin+ fraction. We incubated WBM from B6.SJL mice with fluorescently tagged antibodies directed against TER119, B220, or T-cell markers (CD3, CD4, CD8), isolated the distinct Lin+ subsets by FACS, and then competitively engrafted each Lin+ subset into lethally irradiated C57BL/6 host mice. Donor chimerism and lineage specificity of donor cells in peripheral blood were analyzed by flow cytometry at 3 months. Although classically considered devoid of stem cell activity, we found that, when competed against equal numbers of C57BL/6 WBM, the TER119+ and B220+ B6.SJL donor cells contributed to 33% and 13% of the peripheral blood chimerism, respectively. In both cases, the engraftment was multi-lineage. When 70,000 T cell marker+ donor cells were competed with 300,000 C57BL/6 WBM, the donor cells contributed up to 1.6% of the peripheral blood multi-lineage chimerism. Given the size of the Lin+ fraction in WBM, such chimerism indicates a significant stem cell potential within this typically discarded population. Further time-points, secondary transplants and limited dilution studies are in progress to further define the prevalence and potency of this stem cell population. We have been testing mechanisms governing the loss of this stem cell population during HSC purification. First, we have previously shown that bulk Lin+ engraftment potential is due to cycling stem cells. We hypothesize that fluctuations in surface epitope expression with cell cycle transit render this population difficult to isolate with antibody-mediated strategies that rely on stable epitope expression. To begin testing this, we tracked the fluctuation of stem cell markers on Lin- cells in vitro. We isolated Lin- cells that were also negative for the stem cell markers c-Kit and Sca-1, placed them in liquid culture and, 18 hours later, re-assessed for stem cell marker expression by flow cytometry. We found that, although initially stem cell marker negative, up to 6%, 14%, and 2% of the Lin-/stem cell marker negative cells became positive for c-Kit alone, Sca-1 alone, or both c-Kit and Sca-1 expression, respectively. We are currently testing this population for a correlation between gain of c-Kit- and Sca-1 expression and stem cell function. Second, it is possible that there is a distinct subset of HSCs that are positive for both Lin+ markers and stem cell markers with stable stem cell capacity and that these distinct stem cells are thrown out in the process of lineage depletion. To begin testing this hypothesis, we have simultaneously stained WBM with antibodies directed against the Lin+ markers and conventional stem cell markers. Our preliminary data indicate that each Lin+ fraction tested to date has a subpopulation that is also positive for c-Kit and Sca-1. For example, 21% of CD3+ cells, 6.2% of CD4+ cells, 2.26% of CD8+ cells, 0.5% of B220+, and 0.45% of TER119+ cells express both c-Kit and Sca-1. We suspect these two populations have distinct functional phenotypes and experiments characterizing the molecular phenotype and engraftment capacity of these subpopulations are ongoing. In sum, our data indicate that stem cell purification skews isolation towards a small population of quiescent stem cells, underrepresenting a potentially large pool of actively cycling HSCs that are found within the Lin+ fraction. These data underscore the need to re-evaluate the total hematopoietic stem cell potential in marrow on a population level. Disclosures No relevant conflicts of interest to declare.

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Phenotypic and Functional Changes Induced at the Clonal Level in Hematopoietic Stem Cells After 5-Fluorouracil Treatment

Blood ◽

10.1182/blood.v89.10.3596 ◽

1997 ◽

Vol 89 (10) ◽

pp. 3596-3606 ◽

Cited By ~ 195

Author(s):

Troy D. Randall ◽

Irving L. Weissman

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Cell Population ◽

Stem Cell Population ◽

Normal Bone Marrow ◽

Hematopoietic Stem ◽

Normal Bone

Abstract A significant fraction of hematopoietic stem cells (HSCs) have been shown to be resistant to the effects of cytotoxic agents such as 5-fluorouracil (5-FU), which is thought to eliminate many of the rapidly dividing, more committed progenitors in the bone marrow and to provide a relatively enriched population of the most primitive hematopoietic progenitor cells. Although differences between 5-FU–enriched progenitor populations and those from normal bone marrow have been described, it remained unclear if these differences reflected characteristics of the most primitive stem cells that were revealed by 5-FU, or if there were changes in the stem-cell population itself. Here, we have examined some of the properties of the stem cells in the bone marrow before and after 5-FU treatment and have defined several activation-related changes in the stem-cell population. We found that long-term reconstituting stem cells decrease their expression of the growth factor receptor c-kit by 10-fold and increase their expression of the integrin Mac-1 (CD11b). These changes begin as early as 24 hours after 5-FU treatment and are most pronounced within 2 to 3 days. This activated phenotype of HSCs isolated from 5-FU–treated mice is similar to the phenotype of stem cells found in the fetal liver and to the phenotype of transiently repopulating progenitors in normal bone marrow. We found that cell cycle is induced concomitantly with these physical changes, and within 2 days as many as 29% of the stem-cell population is in the S/G2/M phases of the cell cycle. Furthermore, when examined at a clonal level, we found that 5-FU did not appear to eliminate many of the transient, multipotent progenitors from the bone marrow that were found to be copurified with long-term repopulating, activated stem cells. These results demonstrate the sensitivity of the hematopoietic system to changes in its homeostasis and correlate the expression of several important surface molecules with the activation state of HSCs.

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Cell-Intrinsic Heterogeneity Plays An Important Role in the Development of Clonal Dominance after Retroviral Gene Transfer into Hematopoietic Stem Cells

Blood ◽

10.1182/blood.v112.11.819.819 ◽

2008 ◽

Vol 112 (11) ◽

pp. 819-819

Author(s):

Olga S. Kustikova ◽

Bernhard Schiedlmeier ◽

Martijn H. Brugman ◽

Maike Stahlhut ◽

Zhixiong Li ◽

...

Keyword(s):

Stem Cells ◽

Gene Therapy ◽

Stem Cell ◽

Hematopoietic Stem Cells ◽

Insertional Mutagenesis ◽

Cell Potential ◽

Hematopoietic Stem ◽

Long Term Follow Up ◽

Stem Cell Potential

Abstract The development of clonal imbalance after transplantation of genetically modified hematopoietic cells is a cause of concern in the long-term follow-up of patients undergoing gene therapy for the treatment of severe or acquired hematopoietic disorders. We and others have previously described how insertional proto-oncogene dysregulation by transgene integration may provoke clonal restriction and leukemia, thus becoming a dose-limiting toxicity of gene therapy. When targeting populations enriched for or depleted from hematopoietic stem cells (HSC) in the C57Bl6 CD45 chimerism model, we found that intrinsic stem cell potential is a conditio sine qua non for the establishment of expanding insertional mutants. Mice observed for 6–7 months after co-transplantation of gene-modified cells and non-transduced fresh competitor cells were monitored in regular intervals of 6 weeks and the emergence of dominant clones was assessed by flow cytometry in combination with an LM-PCR procedure validated on mixtures of polyclonal and oligoclonal DNA. Dominant clones originating after gammaretroviral insertion in the Evi1 locus reproducibly occurred with a frequency of 1:10,000 when targeting multipotent LSK cells or short-term repopulating HSC (LSK CD34+ CD135−), but no such events were detected in the progeny of >1 million Sca1- Lin- c-Kit+ (LK) cells or ~75,000 multipotent progenitor cells (MPP, LSK CD34+ CD135+). Dominant clones originating from multipotent cells and displaying insertional upregulation of Evi1 showed greatly diminished T lymphopoiesis in vivo, formally demonstrating transforming events. Residual progeny of MPP or LK cells was detected in transplanted animals with insertional events in proto-oncogenes, but these clones were unable to expand to significant levels of hematopoiesis (>1%). Targeting HSC-enriched cell populations (LSK CD34+ CD135− or LSK CD34− CD135−), a comparison of gamma-retroviral transduction conditions in a 5 days serum-free culture period and lentiviral transduction in a 20h protocol revealed that the latter conditions significantly improved chimerism with a greatly increased clonal diversity in the first 8 weeks of repopulation. However, after lentiviral transduction clonal dominance progressively developed over an observation time of 6 months, although there was no evidence for insertional proto-oncogene upregulation as the underlying cause even when using a lentiviral vector with a strong internal enhancer-promoter capable of insertional long-distance effects. Our study suggests two important conclusions: (1) Insertional mutagenesis in gene therapy is unlikely to endow differentiating progenitor cells with (leukemogenic) stem cell potential and (2) clonal restriction developing in the long-term follow-up after transplantation of gene-modified hematopoietic stem cells is not necessarily a side effect of insertional mutagenesis, but may also reflect classical “gene marking” of a stem cell clone with a strong intrinsic potential for competitive dominance.

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Phenotypic and Functional Changes Induced at the Clonal Level in Hematopoietic Stem Cells After 5-Fluorouracil Treatment

Blood ◽

10.1182/blood.v89.10.3596.3596_3596_3606 ◽

1997 ◽

Vol 89 (10) ◽

pp. 3596-3606 ◽

Cited By ~ 9

Author(s):

Troy D. Randall ◽

Irving L. Weissman

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Cell Population ◽

Stem Cell Population ◽

Normal Bone Marrow ◽

Hematopoietic Stem ◽

Normal Bone

A significant fraction of hematopoietic stem cells (HSCs) have been shown to be resistant to the effects of cytotoxic agents such as 5-fluorouracil (5-FU), which is thought to eliminate many of the rapidly dividing, more committed progenitors in the bone marrow and to provide a relatively enriched population of the most primitive hematopoietic progenitor cells. Although differences between 5-FU–enriched progenitor populations and those from normal bone marrow have been described, it remained unclear if these differences reflected characteristics of the most primitive stem cells that were revealed by 5-FU, or if there were changes in the stem-cell population itself. Here, we have examined some of the properties of the stem cells in the bone marrow before and after 5-FU treatment and have defined several activation-related changes in the stem-cell population. We found that long-term reconstituting stem cells decrease their expression of the growth factor receptor c-kit by 10-fold and increase their expression of the integrin Mac-1 (CD11b). These changes begin as early as 24 hours after 5-FU treatment and are most pronounced within 2 to 3 days. This activated phenotype of HSCs isolated from 5-FU–treated mice is similar to the phenotype of stem cells found in the fetal liver and to the phenotype of transiently repopulating progenitors in normal bone marrow. We found that cell cycle is induced concomitantly with these physical changes, and within 2 days as many as 29% of the stem-cell population is in the S/G2/M phases of the cell cycle. Furthermore, when examined at a clonal level, we found that 5-FU did not appear to eliminate many of the transient, multipotent progenitors from the bone marrow that were found to be copurified with long-term repopulating, activated stem cells. These results demonstrate the sensitivity of the hematopoietic system to changes in its homeostasis and correlate the expression of several important surface molecules with the activation state of HSCs.

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A novel stem-cell population in adult liver with potent hematopoietic-reconstitution activity

Blood ◽

10.1182/blood-2005-03-1017 ◽

2005 ◽

Vol 106 (5) ◽

pp. 1574-1580 ◽

Cited By ~ 40

Author(s):

Darrell N. Kotton ◽

Attila J. Fabian ◽

Richard C. Mulligan

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Side Population ◽

Extramedullary Hematopoiesis ◽

Stem Cell Marker ◽

Stem Cell Population ◽

Hematopoietic Stem ◽

Hematopoietic Reconstitution ◽

Tip Cells

Abstract A number of recent reports have documented that cells possessing hematopoietic-reconstitution ability can be identified and isolated from a variety of solid organs in the adult animal. In all studies to date, however, purified organ-derived stem cells demonstrate a diminished repopulating capacity relative to that of purified bone marrow–derived hematopoietic stem cells (BM HSCs). It has therefore been unclear whether organ-derived HSCs possess functional properties distinct from those of BM HSCs, or simply have not been purified to a comparable extent. Here we report the identification of a rare subset of cells in adult murine liver that possess potent blood-repopulating potential, approaching that of BM HSCs. The cells, isolated on the basis of dye-efflux activity and CD45 expression (termed CD45+ liver side population [SP] tip cells), exhibit a surface phenotype similar to that of freshly isolated BM HSCs derived from normal adult animals, but are phenotypically distinct in that they do not express the stem-cell marker c-kit. Single-cell transplantation studies indicate that CD45+ liver SP tip cells can be generated from BM HSCs, suggesting a relationship between stem-cell populations in the liver and bone marrow compartments. Overall, these studies have important implications for understanding extramedullary hematopoiesis, and may be relevant to current strategies aimed at inducing tolerance to transplanted organs.

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Long-term repopulation of irradiated mice with limiting numbers of purified hematopoietic stem cells: in vivo expansion of stem cell phenotype but not function

Blood ◽

10.1182/blood.v85.4.1006.bloodjournal8541006 ◽

1995 ◽

Vol 85 (4) ◽

pp. 1006-1016 ◽

Cited By ~ 245

Author(s):

GJ Spangrude ◽

DM Brooks ◽

DB Tumas

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Cell Surface ◽

Hematopoietic Stem Cells ◽

Peripheral Blood ◽

Antigen Expression ◽

Hematopoietic Stem ◽

Surface Antigen Expression

Hematopoietic stem cells were isolated from normal adult mouse bone marrow based on surface antigen expression (Thy-1.1(low)Lin(neg)Ly- 6A/E+) and further selected for low retention of rhodamine 123. This population of cells (Rh-123low) could mediate radioprotection and long- term (greater than 12 months) repopulation after transplantation of as few as 25 cells. Transfer of five genetically marked Rh-123low cells in the presence of 10(5) normal bone marrow cells resulted in reconstitution of peripheral blood by greater than 10% donor cells in 64% (30 of 47) of recipient mice. Of 46 animals surviving after 24 weeks, 10 had over 50% donor-derived cells in peripheral blood. Two general patterns of long-term reconstitution were observed: one in which many donor-derived cells were observed 5 to 6 weeks after reconstitution and another in which donor-derived cells were rare initially but expanded with time. This result suggests that two classes of long-term repopulating hematopoietic stem cells exist, differing in their ability to function early in the course of transplantation. Alternatively, distinct anatomic sites of engraftment may dictate these two outcomes from a single type of cell. As an approach to measure the extent of self-renewal by the injected cells, recipients of five or 200 stem cells were killed 8 to 13 months after the transplants, and Thy- 1.1(low)Lin(neg)Ly-6A/E+ progeny of the original injected cells were isolated for a second transplant. While a numerical expansion of cells expressing the cell surface phenotype of stem cells was observed, along with activity in the colony-forming unit-spleen assay, the expanded cells were vastly inferior in radioprotection and long-term reconstitution assays when compared with cells freshly isolated from normal animals. This result demonstrates that in stem cell expansion experiments, cell surface antigen expression is not an appropriate indicator of stem cell function.

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Mobilization of long-term reconstituting hematopoietic stem cells in mice by recombinant human interleukin 7.

Journal of Experimental Medicine ◽

10.1084/jem.181.1.369 ◽

1995 ◽

Vol 181 (1) ◽

pp. 369-374 ◽

Cited By ~ 26

Author(s):

K J Grzegorzewski ◽

K L Komschlies ◽

S E Jacobsen ◽

F W Ruscetti ◽

J R Keller ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Peripheral Blood ◽

Peripheral Blood Leukocytes ◽

Gene Modification ◽

Blood Leukocytes ◽

Hematopoietic Stem ◽

Interleukin 7 ◽

Cell Repopulation

Administration of recombinant human interleukin 7 (rh)IL-7 to mice has been reported by our group to increase the exportation of myeloid progenitors (colony-forming unit [CFU]-c and CFU-granulocyte erythroid megakarocyte macrophage) from the bone marrow to peripheral organs (blood, spleen[s], and liver). We now report that IL-7 also stimulates a sixfold increase in the number of more primitive CFU-S day 8 (CFU-S8) and day 12 (CFU-S12) in the peripheral blood leukocytes (PBL) of mice treated with rhIL-7 for 7 d. Moreover, > 90% of lethally irradiated recipient mice that received PBL from rhIL-7-treated donor mice have survived for > 6 mo whereas none of the recipient mice that received an equal number of PBL from diluent-treated donors survived. Flow cytometry analysis at 3 and 6 mo after transplantation revealed complete trilineage (T, B, and myelomonocytic cell) repopulation of bone marrow, thymus, and spleen by blood-borne stem/progenitor cells obtained from rhIL-7-treated donor mice. Thus, IL-7 may prove valuable for mobilizing pluripotent stem cells with long-term repopulating activity from the bone marrow to the peripheral blood for the purpose of gene modification and/or autologous or allogeneic stem cell transplantation.

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Self-repopulating recipient bone marrow resident macrophages promote long-term hematopoietic stem cell engraftment

Blood ◽

10.1182/blood-2018-01-829663 ◽

2018 ◽

Vol 132 (7) ◽

pp. 735-749 ◽

Cited By ~ 23

Author(s):

Simranpreet Kaur ◽

Liza J. Raggatt ◽

Susan M. Millard ◽

Andy C. Wu ◽

Lena Batoon ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Hematopoietic Stem ◽

Cell Engraftment ◽

Key Points ◽

Bone Marrow Engraftment

Key Points Recipient macrophages persist in hematopoietic tissues and self-repopulate via in situ proliferation after syngeneic transplantation. Targeted depletion of recipient CD169+ macrophages after transplant impaired long-term bone marrow engraftment of hematopoietic stem cells.

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Osteoblast ablation reduces normal long-term hematopoietic stem cell self-renewal but accelerates leukemia development

Blood ◽

10.1182/blood-2014-06-582924 ◽

2015 ◽

Vol 125 (17) ◽

pp. 2678-2688 ◽

Cited By ~ 64

Author(s):

Marisa Bowers ◽

Bin Zhang ◽

Yinwei Ho ◽

Puneet Agarwal ◽

Ching-Cheng Chen ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Hematopoietic Stem Cells ◽

Hematopoietic Stem Cell ◽

Self Renewal ◽

Hematopoietic Stem ◽

Key Points ◽

Leukemia Development

Key Points Bone marrow OB ablation leads to reduced quiescence, long-term engraftment, and self-renewal capacity of hematopoietic stem cells. Significantly accelerated leukemia development and reduced survival are seen in transgenic BCR-ABL mice following OB ablation.

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