scholarly journals Rapid and sustained hematopoietic recovery in lethally irradiated mice transplanted with purified Thy-1.1lo Lin-Sca-1+ hematopoietic stem cells

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3758-3779 ◽  
Author(s):  
N Uchida ◽  
HL Aguila ◽  
WH Fleming ◽  
L Jerabek ◽  
IL Weissman
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Blood Cells ◽  
Critical Role ◽  
White Blood Cells ◽  
Cell Types ◽  
Dose Dependence ◽  
Hematopoietic Stem ◽  
Hematopoietic Recovery

Abstract Hematopoietic stem cells (HSCs) are believed to play a critical role in the sustained repopulation of all blood cells after bone marrow transplantation (BMT). However, understanding the role of HSCs versus other hematopoietic cells in the quantitative reconstitution of various blood cell types has awaited methods to isolate HSCs. A candidate population of mouse HSCs, Thy-1.1lo Lin-Sca-1+ cells, was isolated several years ago and, recently, this population has been shown to be the only population of BM cells that contains HSCs in C57BL/Ka-Thy-1.1 mice. As few as 100 of these cells can radioprotect 95% to 100% of irradiated mice, resulting long-term multilineage reconstitution. In this study, we examined the reconstitution potential of irradiated mice transplanted with purified Thy-1.1lo Lin-Sca-1+ BM cells. Donor-derived peripheral blood (PB) white blood cells were detected as early as day 9 or 10 when 100 to 1,000 Thy-1.1lo Lin-Sca-1+ cells were used, with minor dose-dependent differences. The reappearance of platelets by day 14 and thereafter was also seen at all HSC doses (100 to 1,000 cells), with a slight dose-dependence. All studied HSC doses also allowed RBC levels to recover, although at the 100 cell dose a delay in hematocrit recovery was observed at day 14. When irradiated mice were transplanted with 500 Thy-1.1lo Lin-Sca-1+ cells compared with 1 x 10(6) BM cells (the equivalent amount of cells that contain 500 Thy-1.1lo Lin-Sca-1+ cells as well as progenitor and mature cells), very little difference in the kinetics of recovery of PB, white blood cells, platelets, and hematocrit was observed. Surprisingly, even when 200 Thy1.1lo Lin-Sca- 1+ cells were mixed with 4 x 10(5) Sca-1- BM cells in a competitive repopulation assay, most of the early (days 11 and 14) PB myeloid cells were derived from the HSC genotype, indicating the superiority of the Thy-1.1lo Lin-Sca-1+ cells over Sca-1- cells even in the early phases of myeloid reconstitution. Within the Thy-1.1lo Lin-Sca-1+ population, the Rhodamine 123 (Rh123)hi subset dominates in PB myeloid reconstitution at 10 to 14 days, only to be overtaken by the Rh123lo subset at 3 weeks and thereafter. These findings indicate that HSCs can account for the early phase of hematopoietic recovery, as well as sustained hematopoiesis, and raise questions about the role of non-HSC BM populations in the setting of BMT.

scholarly journals Rapid and sustained hematopoietic recovery in lethally irradiated mice transplanted with purified Thy-1.1lo Lin-Sca-1+ hematopoietic stem cells

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3758-3779 ◽  
Author(s):  
N Uchida ◽  
HL Aguila ◽  
WH Fleming ◽  
L Jerabek ◽  
IL Weissman
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Blood Cells ◽  
Critical Role ◽  
White Blood Cells ◽  
Cell Types ◽  
Dose Dependence ◽  
Hematopoietic Stem ◽  
Hematopoietic Recovery

Hematopoietic stem cells (HSCs) are believed to play a critical role in the sustained repopulation of all blood cells after bone marrow transplantation (BMT). However, understanding the role of HSCs versus other hematopoietic cells in the quantitative reconstitution of various blood cell types has awaited methods to isolate HSCs. A candidate population of mouse HSCs, Thy-1.1lo Lin-Sca-1+ cells, was isolated several years ago and, recently, this population has been shown to be the only population of BM cells that contains HSCs in C57BL/Ka-Thy-1.1 mice. As few as 100 of these cells can radioprotect 95% to 100% of irradiated mice, resulting long-term multilineage reconstitution. In this study, we examined the reconstitution potential of irradiated mice transplanted with purified Thy-1.1lo Lin-Sca-1+ BM cells. Donor-derived peripheral blood (PB) white blood cells were detected as early as day 9 or 10 when 100 to 1,000 Thy-1.1lo Lin-Sca-1+ cells were used, with minor dose-dependent differences. The reappearance of platelets by day 14 and thereafter was also seen at all HSC doses (100 to 1,000 cells), with a slight dose-dependence. All studied HSC doses also allowed RBC levels to recover, although at the 100 cell dose a delay in hematocrit recovery was observed at day 14. When irradiated mice were transplanted with 500 Thy-1.1lo Lin-Sca-1+ cells compared with 1 x 10(6) BM cells (the equivalent amount of cells that contain 500 Thy-1.1lo Lin-Sca-1+ cells as well as progenitor and mature cells), very little difference in the kinetics of recovery of PB, white blood cells, platelets, and hematocrit was observed. Surprisingly, even when 200 Thy1.1lo Lin-Sca- 1+ cells were mixed with 4 x 10(5) Sca-1- BM cells in a competitive repopulation assay, most of the early (days 11 and 14) PB myeloid cells were derived from the HSC genotype, indicating the superiority of the Thy-1.1lo Lin-Sca-1+ cells over Sca-1- cells even in the early phases of myeloid reconstitution. Within the Thy-1.1lo Lin-Sca-1+ population, the Rhodamine 123 (Rh123)hi subset dominates in PB myeloid reconstitution at 10 to 14 days, only to be overtaken by the Rh123lo subset at 3 weeks and thereafter. These findings indicate that HSCs can account for the early phase of hematopoietic recovery, as well as sustained hematopoiesis, and raise questions about the role of non-HSC BM populations in the setting of BMT.

scholarly journals Critical Role of Thrombopoietin in Maintaining Adult Quiescent Hematopoietic Stem Cells

2007 ◽  
Vol 1 (6) ◽  
pp. 671-684 ◽  
Author(s):  
Hong Qian ◽  
Natalija Buza-Vidas ◽  
Craig D. Hyland ◽  
Christina T. Jensen ◽  
Jennifer Antonchuk ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Hematopoietic Stem

scholarly journals The critical role of agrin in the hematopoietic stem cell niche

Blood ◽  
2011 ◽  
Vol 118 (10) ◽  
pp. 2733-2742 ◽  
Author(s):  
Cristina Mazzon ◽  
Achille Anselmo ◽  
Javier Cibella ◽  
Cristiana Soldani ◽  
Annarita Destro ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Hematopoietic Stem ◽  
Hematopoietic Stem Cell Niche ◽  
Cell Niche ◽  
Deficient Mice

Abstract Hematopoiesis is the process leading to the sustained production of blood cells by hematopoietic stem cells (HSCs). Growth, survival, and differentiation of HSCs occur in specialized microenvironments called “hematopoietic niches,” through molecular cues that are only partially understood. Here we show that agrin, a proteoglycan involved in the neuromuscular junction, is a critical niche-derived signal that controls survival and proliferation of HSCs. Agrin is expressed by multipotent nonhematopoietic mesenchymal stem cells (MSCs) and by differentiated osteoblasts lining the endosteal bone surface, whereas Lin−Sca1+c-Kit+ (LSK) cells express the α-dystroglycan receptor for agrin. In vitro, agrin-deficient MSCs were less efficient in supporting proliferation of mouse Lin−c-Kit+ cells, suggesting that agrin plays a role in the hematopoietic cell development. These results were indeed confirmed in vivo through the analysis of agrin knockout mice (Musk-L;Agrn−/−). Agrin-deficient mice displayed in vivo apoptosis of CD34+CD135− LSK cells and impaired hematopoiesis, both of which were reverted by an agrin-sufficient stroma. These data unveil a crucial role of agrin in the hematopoietic niches and in the cross-talk between stromal and hematopoietic stem cells.

scholarly journals Mitochondria in the maintenance of hematopoietic stem cells: new perspectives and opportunities

Blood ◽  
2019 ◽  
Vol 133 (18) ◽  
pp. 1943-1952 ◽  
Author(s):  
Marie-Dominique Filippi ◽  
Saghi Ghaffari
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Blood Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Cellular Energy ◽  
Cell Pool ◽  
Stem Cell Pool

Abstract The hematopoietic system produces new blood cells throughout life. Mature blood cells all derived from a pool of rare long-lived hematopoietic stem cells (HSCs) that are mostly quiescent but occasionally divide and self-renew to maintain the stem cell pool and to insure the continuous replenishment of blood cells. Mitochondria have recently emerged as critical not only for HSC differentiation and commitment but also for HSC homeostasis. Mitochondria are dynamic organelles that orchestrate a number of fundamental metabolic and signaling processes, producing most of the cellular energy via oxidative phosphorylation. HSCs have a relatively high amount of mitochondria that are mostly inactive. Here, we review recent advances in our understanding of the role of mitochondria in HSC homeostasis and discuss, among other topics, how mitochondrial dynamism and quality control might be implicated in HSC fate, self-renewal, and regenerative potential.

scholarly journals Critical Role of Jak2 in the Maintenance and Function of Adult Hematopoietic Stem Cells

Stem Cells ◽  
2014 ◽  
Vol 32 (7) ◽  
pp. 1878-1889 ◽  
Author(s):  
Hajime Akada ◽  
Saeko Akada ◽  
Robert E. Hutchison ◽  
Kazuhito Sakamoto ◽  
Kay-Uwe Wagner ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Hematopoietic Stem ◽  
And Function

scholarly journals Glutamylation of deubiquitinase BAP1 controls self-renewal of hematopoietic stem cells and hematopoiesis

2019 ◽  
Vol 217 (2) ◽  
Author(s):  
Zhen Xiong ◽  
Pengyan Xia ◽  
Xiaoxiao Zhu ◽  
Jingjing Geng ◽  
Shuo Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Peripheral Blood Cells ◽  
Self Renewal ◽  
Hematopoietic Stem

All hematopoietic lineages are derived from a limited pool of hematopoietic stem cells (HSCs). Although the mechanisms underlying HSC self-renewal have been extensively studied, little is known about the role of protein glutamylation and deglutamylation in hematopoiesis. Here, we show that carboxypeptidase CCP3 is most highly expressed in BM cells among CCP members. CCP3 deficiency impairs HSC self-renewal and hematopoiesis. Deubiquitinase BAP1 is a substrate for CCP3 in HSCs. BAP1 is glutamylated at Glu651 by TTLL5 and TTLL7, and BAP1-E651A mutation abrogates BAP1 glutamylation. BAP1 glutamylation accelerates its ubiquitination to trigger its degradation. CCP3 can remove glutamylation of BAP1 to promote its stability, which enhances Hoxa1 expression, leading to HSC self-renewal. Bap1E651A mice produce higher numbers of LT-HSCs and peripheral blood cells. Moreover, TTLL5 and TTLL7 deficiencies sustain BAP1 stability to promote HSC self-renewal and hematopoiesis. Therefore, glutamylation and deglutamylation of BAP1 modulate HSC self-renewal and hematopoiesis.

Critical Role Of Jak2 In The Maintenance and Function Of Adult Hematopoietic Stem Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1180-1180
Author(s):  
Hajime Akada ◽  
Saeko Akada ◽  
Golam Mohi
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Receptor Protein ◽  
Specific Gene ◽  
Hematopoietic Stem ◽  
And Function

Abstract Hematopoietic stem cells (HSCs) play an essential role in the long-term maintenance of hematopoiesis. Various intracellular signaling proteins, transcription factors and extracellular matrix proteins contribute to the maintenance and function of HSCs. Jak2, a member of the Janus family of non-receptor protein tyrosine kinases, is activated in response to a variety of cytokines. It has been shown that germ-line deletion of Jak2 results in embryonic lethality whereas post-natal or adult stage deletion of Jak2 results in anemia and thrombocytopenia in mice. However, the role of Jak2 in the maintenance and function of adult HSCs has remained elusive. Understanding the normal function of Jak2 in adult HSC/progenitors is of considerable significance since mutations in Jak2 have been associated with several myeloproliferative neoplasms (MPNs), and most patients treated with Jak2 inhibitors exhibit significant hematopoietic toxicities. To assess the role of Jak2 in adult HSCs, we have utilized a conditional Jak2 knock-out (Jak2 floxed) allele and an inducible MxCre line that can efficiently express Cre recombinase in adult HSC/progenitors after injections with polyinosine-polycytosine (pI-pC). We have found that deletion of Jak2 in adult mice results in pancytopenia, bone marrow aplasia and 100% lethality within 25 to 42 days after pI-pC induction. Analysis of the HSC/progenitor compartments revealed that Jak2-deficiency causes marked decrease in long-term HSCs, short-term HSCs, multipotent progenitors and early progenitors of all hematopoietic lineages, indicating a defect at the earliest stage of adult hematopoietic development. We have found that deletion of Jak2 leads to increased HSC cell cycle entry, suggesting that Jak2-deficiency results in loss of quiescence in HSCs. Jak2-deficiency also resulted in significant apoptosis in HSCs. Furthermore Jak2-deficient bone marrow cells were severely defective in reconstituting hematopoiesis in lethally-irradiated recipient animals. Competitive repopulations experiments also show that Jak2 is essential for HSC functional activity. We also have confirmed that the requirement for Jak2 in HSCs is cell-autonomous. To gain insight into the mechanism by which Jak2 controls HSC maintenance and function, we have performed phospho flow analysis on HSC-enriched LSK (lin-Sca-1+c-kit+) cells. TPO and SCF-evoked Akt and Erk activation was significantly reduced in Jak2-deficient LSK compared with control LSK. Stat5 phosphorylation in response to TPO was also completely inhibited in Jak2-deficient LSK cells. In addition, we observed significantly increased intracellular reactive oxygen species (ROS) levels and enhanced activation of p38 MAPK in Jak2-deficient LSK cells, consistent with the loss of quiescence observed in Jak2-deficient HSCs. Treatment with ROS scavenger N-acetyl cysteine partially rescued the defects in Jak2-deficient HSCs in reconstituting hematopoiesis in lethally irradiated recipient animals. Gene expression analysis revealed significant downregulation of HSC-specific gene sets in Jak2-deficient LSK cells. Taken together, our data strongly suggest that Jak2 plays a critical role in the maintenance of quiescence, survival and self-renewal of adult HSCs. Disclosures: No relevant conflicts of interest to declare.

scholarly journals SETD5 modulates homeostasis of hematopoietic stem cells by mediating RNA Polymerase II pausing in cooperation with HCF-1

Leukemia ◽  
2021 ◽  
Author(s):  
Mengke Li ◽  
Chen Qiu ◽  
Yujie Bian ◽  
Deyang Shi ◽  
Bichen Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Rna Polymerase ◽  
Hematopoietic Stem Cells ◽  
Rna Polymerase Ii ◽  
Critical Role ◽  
Whole Body ◽  
Hematopoietic Stem ◽  
Pol Ii

AbstractSETD5 mutations were identified as the genetic causes of neurodevelopmental disorders. While the whole-body knockout of Setd5 in mice leads to embryonic lethality, the role of SETD5 in adult stem cell remains unexplored. Here, a critical role of Setd5 in hematopoietic stem cells (HSCs) is identified. Specific deletion of Setd5 in hematopoietic system significantly increased the number of immunophenotypic HSCs by promoting HSC proliferation. Setd5-deficient HSCs exhibited impaired long-term self-renewal capacity and multiple-lineage differentiation potentials under transplantation pressure. Transcriptome analysis of Setd5-deficient HSCs revealed a disruption of quiescence state of long-term HSCs, a cause of the exhaustion of functional HSCs. Mechanistically, SETD5 was shown to regulate HSC quiescence by mediating the release of promoter-proximal paused RNA polymerase II (Pol II) on E2F targets in cooperation with HCF-1 and PAF1 complex. Taken together, these findings reveal an essential role of SETD5 in regulating Pol II pausing-mediated maintenance of adult stem cells.

scholarly journals Essential role for Gata2 in modulating lineage output from hematopoietic stem cells in zebrafish

2021 ◽  
Vol 5 (13) ◽  
pp. 2687-2700
Author(s):  
Emanuele Gioacchino ◽  
Cansu Koyunlar ◽  
Joke Zink ◽  
Hans de Looper ◽  
Madelon de Jong ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Cell Types ◽  
Relative Increase ◽  
Hematopoietic Stem ◽  
Lineage Differentiation ◽  
Early Embryonic Lethality ◽  
Different Cell Types ◽  
Proper Balance

The differentiation of hematopoietic stem cells (HSCs) is tightly controlled to ensure a proper balance between myeloid and lymphoid cell output. GATA2 is a pivotal hematopoietic transcription factor required for generation and maintenance of HSCs. GATA2 is expressed throughout development, but because of early embryonic lethality in mice, its role during adult hematopoiesis is incompletely understood. Zebrafish contains 2 orthologs of GATA2: Gata2a and Gata2b, which are expressed in different cell types. We show that the mammalian functions of GATA2 are split between these orthologs. Gata2b-deficient zebrafish have a reduction in embryonic definitive hematopoietic stem and progenitor cell (HSPC) numbers, but are viable. This allows us to uniquely study the role of GATA2 in adult hematopoiesis. gata2b mutants have impaired myeloid lineage differentiation. Interestingly, this defect arises not in granulocyte-monocyte progenitors, but in HSPCs. Gata2b-deficient HSPCs showed impaired progression of the myeloid transcriptional program, concomitant with increased coexpression of lymphoid genes. This resulted in a decrease in myeloid-programmed progenitors and a relative increase in lymphoid-programmed progenitors. This shift in the lineage output could function as an escape mechanism to avoid a block in lineage differentiation. Our study helps to deconstruct the functions of GATA2 during hematopoiesis and shows that lineage differentiation flows toward a lymphoid lineage in the absence of Gata2b.

Generation and Characterization of Transgenic Mice Expressing MplW515L.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3901-3901
Author(s):  
Wanming Zhao ◽  
Shu Xing ◽  
Rufei Gao ◽  
Aref Al-Kali ◽  
Wanting Tina Ho ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
B Cells ◽  
Transgenic Mice ◽  
Hematopoietic Stem Cells ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
White Blood Cells ◽  
Hematopoietic Stem

Abstract Abstract 3901 Poster Board III-837 Myeloproliferative neoplasias (MPNs) are a group of conditions characterized by chronic increases in some or all of the blood cells (platelets, white blood cells, and red blood cells). JAK2V617F, a gain-of-function mutation of tyrosine kinase JAK2, is found in over 90% of patients with polycythemia vera (PV) and about 50% of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). Attempt to identify other signaling components involving the JAK2 signaling pathways has led to discovery of acquired mutations of Mpl, the receptor of thrombopoietin, in 5-10% patients with PMF and ET. To prove the pathogenesis of Mpl mutants, we have generated transgenic mice expressing the most frequently occurred Mpl mutant designated MplW515L by using the vav gene promoter which drives expression of transgenes in the hematopoietic system. We obtained three lines of MplW515L transgenic mice which all displayed similar hematological abnormalities. As expected, the mice developed ET- and PMF-like phenotypes with much elevated platelet counts, severe splenomegaly/hepatomegaly, and bone marrow/spleen myelofibrosis. Interestingly, these mice also had markedly increased white blood cells in the peripheral blood, majority of which are IgD-positive mature B-cells. Histochemical staining and flow cytometric analyses revealed infiltrations of megkaryocytes and B cells into the spleen, the presence of megkaryocytes and erythroid blast cells in the liver, and infiltrations of the bone marrow with B-cells. Reticulin staining revealed that MplW515L transgenic mice developed profound myelofibrosis in the bone marrow and spleen. In vitro hematopoietic colony assays demonstrated increased numbers of hematopoietic progenitor cells including BFU-E, CFU-GM, CFU-Mk, and CFU-Pre-B in the bone marrow, mobilization of these stem/progenitor cells to peripheral blood and spleen, and their autonomous growth in the absence of growth factors and cytokines. Finally, transplantation of bone marrow cells from MplW515L mice into irradiated normal mice installed the aforementioned phenotypes into the recipient mice, indicating that expression of MplW515L altered the activity of hematopoietic stem cells. Together, our data demonstrated that transgenic expression of MplW515L not only causes PMF- and ET-like phenotypes but also lymphoproliferative disorders. Considering that Mpl is expressed in hematopoietic stem cells and that oncogenic gene mutations are often associated with alteration of gene expression, we believe that MplW515L may be involved in a wider spectrum of human hematological diseases than MPNs. Disclosures: No relevant conflicts of interest to declare.

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