scholarly journals Pleiotrophin Signaling Is Necessary for Hematopoietic Stem Cell Self Renewal and Is Regulated by the Bone Marrow Microenvironment

2011 ◽  
Vol 17 (2) ◽  
pp. S149
Author(s):  
H.A. Himburg ◽  
P. Daher ◽  
L. Russell ◽  
P. Doan ◽  
M. Quarmyne ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Bone Marrow Microenvironment ◽  
Self Renewal ◽  
Hematopoietic Stem

The histone lysine acetyltransferase HBO1 (KAT7) regulates hematopoietic stem cell quiescence and self-renewal

Blood ◽  
2021 ◽  
Author(s):  
Yuqing Yang ◽  
Andrew J Kueh ◽  
Zoe Grant ◽  
Waruni Abeysekera ◽  
Alexandra L Garnham ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Hematopoietic Stem Cell ◽  
Cell Function ◽  
Bone Marrow Cells ◽  
High Rate ◽  
Embryonic Patterning ◽  
Self Renewal ◽  
Hematopoietic Stem

The histone acetyltransferase HBO1 (MYST2, KAT7) is indispensable for postgastrulation development, histone H3 lysine 14 acetylation (H3K14Ac) and the expression of embryonic patterning genes. In this study, we report the role of HBO1 in regulating hematopoietic stem cell function in adult hematopoiesis. We used two complementary cre-recombinase transgenes to conditionally delete Hbo1 (Mx1-Cre and Rosa26-CreERT2). Hbo1 null mice became moribund due to hematopoietic failure with pancytopenia in the blood and bone marrow two to six weeks after Hbo1 deletion. Hbo1 deleted bone marrow cells failed to repopulate hemoablated recipients in competitive transplantation experiments. Hbo1 deletion caused a rapid loss of hematopoietic progenitors (HPCs). The numbers of lineage-restricted progenitors for the erythroid, myeloid, B-and T-cell lineages were reduced. Loss of HBO1 resulted in an abnormally high rate of recruitment of quiescent hematopoietic stem cells (HSCs) into the cell cycle. Cycling HSCs produced progenitors at the expense of self-renewal, which led to the exhaustion of the HSC pool. Mechanistically, genes important for HSC functions were downregulated in HSC-enriched cell populations after Hbo1 deletion, including genes essential for HSC quiescence and self-renewal, such as Mpl, Tek(Tie-2), Gfi1b, Egr1, Tal1(Scl), Gata2, Erg, Pbx1, Meis1 and Hox9, as well as genes important for multipotent progenitor cells and lineage-specific progenitor cells, such as Gata1. HBO1 was required for H3K14Ac through the genome and particularly at gene loci required for HSC quiescence and self-renewal. Our data indicate that HBO1 promotes the expression of a transcription factor network essential for HSC maintenance and self-renewal in adult hematopoiesis.

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

Blood ◽  
2015 ◽  
Vol 125 (17) ◽  
pp. 2678-2688 ◽  
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.

The F-Box Protein NIPA Regulates the Hematopoietic Stem Cell Pool

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2330-2330
Author(s):  
Stefanie Kreutmair ◽  
Anna Lena Illert ◽  
Rouzanna Istvanffy ◽  
Melanie Sickinger ◽  
Christina Eckl ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Bone Marrow Cells ◽  
Wild Type ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
F Box Protein ◽  
Stem Cell Pool

Abstract Abstract 2330 Hematopoietic stem cells (HSCs) are characterized by their ability to self-renewal and multilineage differentiation. Since mostly HSCs exist in a quiescent state re-entry into cell cycle is essential for their regeneration and differentiation and the expression of numerous cell cycle regulators must be tightly controlled. We previously characterized NIPA (Nuclear Interaction Partner of ALK) as a F-Box protein that defines an oscillating ubiquitin E3 ligase targeting nuclear cyclin B1 in interphase thus contributing to the timing of mitotic entry. To examine the function of NIPA on vivo, we generated NIPA deficient animals, which are viable but sterile due to a defect in recombination and testis stem cell maintenance. To further characterize the role of NIPA in stem cell maintenance and self-renewal we investigated hematopoiesis in NIPA deficient animals. Peripheral blood counts taken at different ages revealed no apparent difference between NIPA knockout and wild type mice in numbers and differentiation. In contrast, looking at the hematopoietic stem cell pool, FACS analyses of bone marrow showed significantly decreased numbers of Lin-Sca1+cKit+ (LSK) cells in NIPA deficient animals, where LSKs were reduced to 40% of wild type littermates (p=0,0171). This effect was only apparent in older animals, where physiologically higher LSK numbers have to compensate for the exhaustion of the stem cell pool. Additionally, older NIPA deficient mice have only half the amount of multi myeloid progenitors (MMPs) in contrast to wild type animals. To examine efficient activation of stem cells to self-renew in response to myeloid depression, we treated young and old mice with the cytotoxic drug (5-FU) four days before bone marrow harvest. As expected, 5-FU activated hematopoietic progenitors in wild type animals, whereas NIPA deficient progenitors failed to compensate to 5-FU depression, e.g. LSKs of NIPA knockout mice were reduced to 50% of wild type levels (p<0.001), CD150+CD34+ Nipa deficient cells to 20% of wild type levels (p<0.0001). Interestingly, these effects were seen in all NIPA deficient animals independent of age, allowing us to trigger the self-renewal phenotype by activating the hematopoietic stem cell pool. Using competitive bone marrow transplantation assays, CD45.2 positive NIPA deficient or NIPA wild type bone marrow cells were mixed with CD45.1 positive wild type bone marrow cells and transplanted into lethally irradiated CD45.2 positive recipient mice. Thirty days after transplantation, FACS analysis of peripheral blood and bone marrow showed reduced numbers of NIPA knockout cells in comparison to NIPA wild type bone marrow recipient mice. This result was even more severe with aging of transplanted mice, where NIPA deficient cells were reduced to less than 10% of the level of wild type cells in bone marrow of sacrificed mice 6 months after transplantation, pointing to a profound defect in repopulation capacity of NIPA deficient HSCs. Taken together our results demonstrate a unique and critical role of NIPA in regulating the primitive hematopoietic compartment as a regulator of self-renewal, cycle capacity and HSC expansion. Disclosures: No relevant conflicts of interest to declare.

G-CSF Treatment Induces Hematopoietic Stem Cell Quiescence but Loss of Repopulating Activity

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1206-1206
Author(s):  
Joshua N. Borgerding ◽  
Priya Gopalan ◽  
Matthew Christopher ◽  
Daniel C. Link ◽  
Laura G. Schuettpelz
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Hematopoietic Stem Cell ◽  
Inflammatory Signaling ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
A Cell

Abstract Abstract 1206 There is accumulating evidence that systemic signals, such as inflammatory cytokines, can affect hematopoietic stem cell (HSC) function. Granulocyte colony stimulating factor (G-CSF), the principal cytokine regulating granulopoiesis, is often induced in response to infection or inflammation. Additionally, G-CSF is the most commonly used agent for HSC mobilization prior to stem cell transplantation. Recently there has been a renewed interest in the use of “G-CSF primed bone marrow” for stem cell transplantation, so understanding the affect of G-CSF on bone marrow HSCs is clinically relevant. Because the G-CSF receptor is expressed on HSCs, and G-CSF creates biologically relevant modifications to the bone marrow microenvironment, we hypothesized that increased signaling through G-CSF may alter the repopulating and/or self-renewal properties of HSCs. Due to G-CSF's role as an HSC mobilizing agent, we predicted that the number of HSCs in the bone marrow would be reduced after 7 days of G-CSF treatment. Surprisingly, we observe that stem cell numbers markedly increase, regardless of which HSC-enriched population is analyzed. C-kit+lineage−sca+CD34− (KLS-34−), KLS CD41lowCD150+CD48− (KLS-SLAM), and KLS-SLAM CD34− increase by 6.97±2.25 fold, 1.79±0.29 fold, and 2.08±0.39 fold, respectively. To assess HSC repopulating activity, we conducted competitive bone marrow transplants. Donor mice were treated with or without G-CSF for 7 days, and bone marrow was transplanted in a 1:1 ratio with marrow from untreated competitors into lethally irradiated congenic recipients. Compared to untreated HSCs, we found that G-CSF treated cells have significantly impaired long-term repopulating and self-renewal activity in transplanted mice. In fact, on a per cell basis, the long-term repopulating activity of KLS-CD34− cells from G-CSF treated mice was reduced approximately 13 fold. The loss of repopulating activity per HSC was confirmed by transplanting purified HSCs. Homing experiments indicate that this loss of function is not caused by an inability to home from the peripheral blood to the bone marrow niche. As HSC quiescence has been positively associated with repopulating activity, we analyzed the cell cycle status over time of KLS-SLAM cells treated with G-CSF. This analysis revealed that after a brief period of enhanced cycling (69.8±5.0% G0 at baseline; down to 55.9±4.1% G0after 24 hours of G-CSF), treated cells become more quiescent (86.8±2.8% G0) than untreated HSCs. A similar increase in HSC quiescence was seen in KLS-34− cells. Thus our data show that G-CSF treatment is associated with HSC cycling alterations and function impairment. Because G-CSF is associated with modifications to the bone marrow microenvironment, and the microenvironment is known to regulate HSCs at steady state, we asked whether the G-CSF induced repopulating defect was due to a cell intrinsic or extrinsic (secondary to alterations in the microenvironment) mechanism. To do this, we repeated the competitive transplantation experiments using chimeric mice with a mixture of wild-type and G-CSF receptor knockout (Csf3r−/−) bone marrow cells. We find that only the repopulating activity of HSCs expressing the G-CSF receptor is affected by G-CSF, suggesting a cell-intrinsic mechanism. To identify targets of G-CSF signaling that may mediate loss of stem cell function, we performed RNA expression profiling of sorted KSL-SLAM cells from mice treated for 36 hours or seven days with or without G-CSF. The profiling data show that G-CSF treatment is associated with activation of inflammatory signaling in HSCs. Studies are in progress to test the hypothesis that activation of specific inflammatory signaling pathways mediates the inhibitory effect of G-CSF on HSC function. In summary, G-CSF signaling in HSCs, although associated with increased HSC quiescence, leads to a marked loss of long-term repopulating activity. These data suggest that long-term engraftment after transplantation of G-CSF-primed bone marrow may be reduced and requires careful follow-up. Disclosures: No relevant conflicts of interest to declare.

Jagged1-dependent Notch signaling is dispensable for hematopoietic stem cell self-renewal and differentiation

Blood ◽  
2005 ◽  
Vol 105 (6) ◽  
pp. 2340-2342 ◽  
Author(s):  
Stéphane J. C. Mancini ◽  
Ned Mantei ◽  
Alexis Dumortier ◽  
Ueli Suter ◽  
H. Robson MacDonald ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Notch Signaling ◽  
Hematopoietic Stem Cell ◽  
Stromal Cells ◽  
Essential Role ◽  
Self Renewal ◽  
Hematopoietic Stem

AbstractJagged1-mediated Notch signaling has been suggested to be critically involved in hematopoietic stem cell (HSC) self-renewal. Unexpectedly, we report here that inducible Cre-loxP–mediated inactivation of the Jagged1 gene in bone marrow progenitors and/or bone marrow (BM) stromal cells does not impair HSC self-renewal or differentiation in all blood lineages. Mice with simultaneous inactivation of Jagged1 and Notch1 in the BM compartment survived normally following a 5FU-based in vivo challenge. In addition, Notch1-deficient HSCs were able to reconstitute mice with inactivated Jagged1 in the BM stroma even under competitive conditions. In contrast to earlier reports, these data exclude an essential role for Jagged1-mediated Notch signaling during hematopoiesis.

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