Effect of methylcellulose injection on murine hematopoiesis

1977 ◽  
Vol 233 (2) ◽  
pp. H234-H239
Author(s):  
H. D. Stang ◽  
D. R. Boggs
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Hemolytic Anemia ◽  
Rat Model ◽  
Extramedullary Hematopoiesis ◽  
Significant Shift ◽  
Hematopoietic Stem ◽  
Hematologic Response ◽  
Hematologic Change ◽  
Number Of Cells

This study was designed to determine the effect of methylcellulose (MC)-induced reticuloendothelial (RE) hypertrophy on neutrophils and hematopoietic stem cells and to contrast its overall hematologic effect in the mouse to the more frequently studied rat model. Mice were given MC 3 times/wk and studies were done at 2, 3, and 4 wk, with maximal hematologic change by 2 wk. A stable, but incompletely compensated hemolytic anemia developed which was accompanied by a significant shift of erythropoiesis from marrow to spleen. Thrombocytopenia developed as did neutrophilia, accompanied by an increased number of marrow neutrophil precursors. Extramedullary hematopoiesis was observed in the liver. The number of cells forming spleen colonies in irradiated recipients increased in the spleen but not in marrow. The number of cells producing granulocyte and macrophage colonies in semisolid media increased in spleen and marrow. Splenectomized mice, treated with MC, developed changes very similar to intact mice. Thus, it appears that all three major hematopoietic lines may be destroyed by the MC-hypertrophied RE system. The mouse differs from the rat in its hematologic response to MC by destroying cells in organs other than the spleen, by increasing neutrophil production, by developing hepatic hematopoiesis, and by developing all changes more rapidly.

Establishment of Mouse PMF Model by the Introduction of Constitutive STAT5a Into Purified Hematopoietic Stem Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3900-3900
Author(s):  
Takafumi Shimizu ◽  
Akihiko Ito ◽  
Akira Nakagawa ◽  
Toshinobu Nishimura ◽  
Satoshi Yamazaki ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Conflicts Of Interest ◽  
Active Form ◽  
Myeloproliferative Neoplasm ◽  
Extramedullary Hematopoiesis ◽  
Hematopoietic Stem ◽  
Pmf Model ◽  
Short Period

Abstract Abstract 3900 Poster Board III-836 Background Polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofiblosis (PMF) are pathologically related and now classified under myeloproliferative neoplasm (MPN). Subsequent studies revealed that MPN is a group of clonal hematopoietic stem cell disorders characterized by proliferation of one or more of the myeloid lineages. The somatic activating mutation in the JAK2 tyrosine kinase, JAK2V617F, is now broadly recognized as a mutation responsible for MPN (Levine R.L. and Gilliland D.G. Blood 2008). Indeed, Most of PV patients, and half of patients with ET or PMF possess this mutation. Recent studies revealed that PV phenotype can be generated in homozygous JAK2V617F transgenic mice, while ET or atypical CML-like marked leukothrombocytosis with mild myelofibrosis can be observed in heterozygous JAK2V617F mice (Tiedt et al, Blood 2008, Shide et al Leukemia 2008). These results indicate that expression levels of JAK2V617F may influence PV and ET phenotypes. On the other hand, typical PMF phenotype has not been generated by the introduction of JAK2V617F. According to the WHO criteria, PMF could be defined as “spent phase of hematopoiesis” with fibrosis formation followed by increased bone marrow cellularity as consequences of granulocytic proliferation and megakaryocyte changes with ineffective hematopoiesis. In this study, we focused on STAT5a, a direct downstream molecule of JAK2, because we previously reported that upon transplantation, purified CD34- lineage- sca-1+ c-Kit+ (CD34-KSL) hematopoietic stem cells (HSCs) transduced with constitutive active form of STAT5A acted as MPN initiating cells causing granulocytosis without erythrocytosis/thrombocytosis (Kato Y. et al, J Exp Med 2005). Based on these observations, we attempted to make PMF model through mimicking typical PMF dynamics; hyper proliferation of HSCs by the introduction of constitutive active STAT5a and following early HSC exhaustion. Materials and Methods CD34-KSL HSCs or CD34+KSL hematopoietic progenitor cells (HPCs) were purified from bone marrow (BM) of C57BL/6 (B6)-Ly5.1 mice. Then, the cells were retrovirally transduced with STAT5a wild-type (wt) or its constitutive active mutant, STAT5a(1*6). The prepared cells were used for methylcellulose assay and were transplanted into lethally irradiated B6-Ly5.2 recipient mice together with 5 × 105 B6-Ly5.1/5.2 competitor BM cells. Peripheral blood (PB) of transplanted mice was monitored biweekly for donor chimerism and lineage deviation using flow cytometry. Subsequently, histrogical analyses of bone marrow and spleen were performed to determine myelofiblosis grade and detecting extramedullar hematopoiesis. Finally, immunohistochemical staining of bone marrow with anti-TGF-b antibody was performed to detect effector cells of myelofibrosis. Results Transplantation of STAT5a (1*6) transduced HSCs resulted in generation of 57 MPN mice (total 83 mice), while no MPN mouse was obtained by STAT5a (1*6) transduced HPCs (total 12 mice). Pathological analysis revealed that majority (70%) of MPN mice had PMF phenotype as defined by leukoerythroblastosis and dacryocytosis without leukothrombocytosis. These mice with PMF phenotype showed marked splenomegaly with extramedullary hematopoiesis, and granulocytic proliferation with megakaryocyte change. In BM, granulocytic proliferation advanced to severe myelofibrosis and osteomyelosclerosis in very short period of time (4 to 8 weeks). Those mice died of hemorrhage induced by pancytopenia within a few months, much faster than the mice with JAK2V617F based PV/ET models. Immunohistological analysis revealed that dominance of Gr-1 / Mac-1 positive granulocytes and CD41 positive small megakaryocytes strongly expressing TGF-beta, a putative inducer of fibroblastosis in BM of PMF mice. Conclusion By transplanting STAT5a(1*6) transduced HSCs, we were able to develop mice with phenotype closely resembling human PMF. Because PMF is rare disease, this animal model should be useful for understanding etiology of PMF, for evaluating existing treatment, and for developing therapeutics targeting STAT5a or its downstream pathway. Disclosures: No relevant conflicts of interest to declare.

Zeb2-Defficiency in the Adult Murine Hematopoietic Precursor Cells Leads to Differentiation Defects in Multiple Hematopoietic Lineages and a Myeloproliferative-Like Phenotype

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1199-1199
Author(s):  
Tamara Riedt ◽  
Steven Goossens ◽  
Ines Gütgemann ◽  
Carmen Carrillo-Garcia ◽  
Hichem D Gallala ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Cells ◽  
Extramedullary Hematopoiesis ◽  
Independent Effect ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Reticular Fibers

Abstract Abstract 1199 The life long replenishment of highly specialized blood cells by a small number of hematopoietic cells (HSC) requires a strict regulation between self-renewal and differentiation in the immature compartment of the bone marrow. Perturbation of this equilibrium can result in stem cell loss or hematologic malignancies. This balance is at least in part controlled by a network of transcription factors. Zeb2 is a transcriptional repressor and plays an important role during the embryonic development as a modulator of the epithelial to mesenchymal transition (EMT) as well as tumor progression and metastasis. We have previously identified the essential role of Zeb2 in murine embryonic hematopoiesis, where selective Zeb2 deficiency in the hematopoietic stem cells resulted in early lethality around day 12.5. The aim of this study was to analyze whether Zeb2 plays a specific role in the regulation of homeostasis in the adult hematopoietic system. Using the Mx1-Cre based inducible Zeb2 conditional knock out mouse model we analyzed the impact of Zeb2 loss on adult hematopoietic stem cell function. Upon the induction of Zeb2 deletion we found a significant decrease in most cell lineages of the peripheral blood, except the neutrophil granulocytes. However, the reduction of mature cells in the blood was not accompanied by reduced bone marrow cellularity, as the cellularity was similar between Zeb2Δ/Δ Mx1-Cre (Zeb2 conditional KO) mice and the control animals (Zeb2+/+Mx1-Cre). However, in the bone marrow of the Zeb2Δ/Δ Mx1-Cre animals the granulocytic lineage was dominating, whereas other lineages e.g. red blood cell precursors and B-lymphoid precursors were drastically reduced. Histological sections of the bone marrow cavity revealed megacaryocytes with abnormal morphology reflecting maturation defects and an increased production of reticular fibers in the BM of Zeb2Δ/Δ Mx1-Cre mice. In addition Zeb2Δ/Δ Mx1-Cre mice displayed a two to three fold increase in spleen size compared to control animals due to an extramedullary hematopoiesis. Analysis of the primitive hematopoietic compartment in the bone marrow and spleens revealed that Zeb2 deletion resulted in a pronounced increase in the most immature hematopoietic cells, defined as Lin-Sca1+cKit+CD48-CD150+ population, and perturbation in different lineage restricted progenitor subpopulations. No difference in cell cycling or apoptotic rate in the stem cell enriched bone marrow population (Lin-Sca1+cKit+CD48-CD150+) was detectable between the genotypes. Upon transplantation into lethally irradiated wild type recipients, Zeb2 deficient stem cells demonstrated significantly reduced ability to differentiate into multiple hematopoietic lineages indicating a niche independent effect of Zeb2 in promoting differentiation of hematopoietic stem cells. On the molecular level, gene expression analysis of hematopoietic stem and progenitor cells using microarray approach revealed increased transcripts of downstream targets of Wnt/ß-Catenin signaling, suggesting increased Wnt signaling activity in absence of Zeb2 in the hematopoietic compartment, which at least in part might be responsible for the observed phenotype. These data indicate that Zeb2 is involved in the regulation of the balance between self-renewal and differentiation at multiple stages of hematopoietic cell maturation. Furthermore the lack of Zeb2 in the hematopoietic compartment leads to a phenotype that resembles the features of human myeloproliferative disorders, especially the early stages of primary myelofibrosis with dominant granulopoiesis, production of reticular fibers in the bone marrow, and morphological abnormalities in megacaryocytes, accompanied by extramedullary hematopoiesis. Disclosures: No relevant conflicts of interest to declare.

Cyclical Neutropenia and Other Periodic Hematological Disorders: A Review of Mechanisms and Mathematical Models

Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2629-2640 ◽  
Author(s):  
Caroline Haurie ◽  
David C. Dale ◽  
Michael C. Mackey
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Hemolytic Anemia ◽  
Cell Loss ◽  
Myelogenous Leukemia ◽  
Hematopoietic Stem ◽  
Hematological Disorders ◽  
Regulatory Processes ◽  
Cyclical Neutropenia ◽  
Immune Hemolytic Anemia

Although all blood cells are derived from hematopoietic stem cells, the regulation of this production system is only partially understood. Negative feedback control mediated by erythropoietin and thrombopoietin regulates erythrocyte and platelet production, respectively, but the regulation of leukocyte levels is less well understood. The local regulatory mechanisms within the hematopoietic stem cells are also not well characterized at this point. Because of their dynamic character, cyclical neutropenia and other periodic hematological disorders offer a rare opportunity to more fully understand the nature of these regulatory processes. We review the salient clinical and laboratory features of cyclical neutropenia (and the less common disorders periodic chronic myelogenous leukemia, periodic auto-immune hemolytic anemia, polycythemia vera, aplastic anemia, and cyclical thrombocytopenia) and the insight into these diseases afforded by mathematical modeling. We argue that the available evidence indicates that the locus of the defect in most of these dynamic diseases is at the stem cell level (auto-immune hemolytic anemia and cyclical thrombocytopenia seem to be the exceptions). Abnormal responses to growth factors or accelerated cell loss through apoptosis may play an important role in the genesis of these disorders. © 1998 by The American Society of Hematology.

scholarly journals CLEC-2 in megakaryocytes is critical for maintenance of hematopoietic stem cells in the bone marrow

2015 ◽  
Vol 212 (12) ◽  
pp. 2133-2146 ◽  
Author(s):  
Ayako Nakamura-Ishizu ◽  
Keiyo Takubo ◽  
Hiroshi Kobayashi ◽  
Katsue Suzuki-Inoue ◽  
Toshio Suda
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Extramedullary Hematopoiesis ◽  
Cell Potential ◽  
Hematopoietic Stem ◽  
Bm Niche ◽  
Proliferation And Differentiation ◽  
Cellular Source ◽  
Stem Cell Potential

Hematopoietic stem cells (HSCs) depend on the bone marrow (BM) niche for their maintenance, proliferation, and differentiation. The BM niche is composed of nonhematopoietic and mature hematopoietic cells, including megakaryocytes (Mks). Thrombopoietin (Thpo) is a crucial cytokine produced by BM niche cells. However, the cellular source of Thpo, upon which HSCs primarily depend, is unclear. Moreover, no specific molecular pathway for the regulation of Thpo production in the BM has been identified. Here, we demonstrate that the membrane protein C-type lectin-like receptor-2 (CLEC-2) mediates the production of Thpo and other factors in Mks. Mice conditionally deleted for CLEC-2 in Mks (Clec2MkΔ/Δ) produced lower levels of Thpo in Mks. CLEC-2–deficient Mks showed down-regulation of CLEC-2–related signaling molecules Syk, Lcp2, and Plcg2. Knockdown of these molecules in cultured Mks decreased expression of Thpo. Clec2MkΔ/Δ mice exhibited reduced BM HSC quiescence and repopulation potential, along with extramedullary hematopoiesis. The low level of Thpo production may account for the decline in HSC potential in Clec2MkΔ/Δ mice, as administration of recombinant Thpo to Clec2MkΔ/Δ mice restored stem cell potential. Our study identifies CLEC-2 signaling as a novel molecular mechanism mediating the production of Thpo and other factors for the maintenance of HSCs.

Interleukin-27 directly induces differentiation in hematopoietic stem cells

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 1903-1912 ◽  
Author(s):  
Jun Seita ◽  
Masayuki Asakawa ◽  
Jun Ooehara ◽  
Shin-ichiro Takayanagi ◽  
Yohei Morita ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Extramedullary Hematopoiesis ◽  
Multiple Roles ◽  
Hematopoietic Stem ◽  
Human Cd34 ◽  
Cd34 Cells ◽  
Common Signal

Interleukin (IL)-27, one of the most recently discovered IL-6 family cytokines, activates both the signal transducer and activator of transcription (STAT)1 and STAT3, and plays multiple roles in pro- and anti-inflammatory immune responses. IL-27 acts on various types of cells including T, B, and macrophage through the common signal-transducing receptor gp130 and its specific receptor WSX-1, but the effect of IL-27 on hematopoietic stem cells (HSCs) remains unknown. Here, we show that IL-27 together with stem cell factor (SCF) directly acts on HSCs and supports their early differentiation in vitro and in vivo. CD34−/lowc-Kit+Sca-1+lineage marker− (CD34−KSL) cells, a population highly enriched in mouse HSCs, were found to express both IL-27 receptor subunits. In vitro cultures of CD34−KSL cells with IL-27 and SCF resulted in an expansion of progenitors including short-term repopulating cells, while some of their long-term repopulating activity also was maintained. To examine its in vivo effect, transgenic mice expressing IL-27 were generated. These mice exhibited enhanced myelopoiesis and impaired B lymphopoiesis in the bone marrow with extramedullary hematopoiesis in the spleen. Moreover, IL-27 similarly acted on human CD34+ cells. These results suggest that IL-27 is one of the limited cytokines that play a role in HSC regulation.

scholarly journals C-MYC Augments the Proliferation and Survival of Hematopoietic Stem Cells and Multipotent Progenitors to Drive Myeloproliferative Neoplasms

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 28-28
Author(s):  
Nicole D. Vincelette ◽  
Jungwon Moon ◽  
Andrew T. Kuykendall ◽  
Ling Zhang ◽  
Rami S. Komrokji ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Hematopoietic Stem Cells ◽  
Ex Vivo ◽  
Myeloproliferative Neoplasms ◽  
Myeloid Cell ◽  
Extramedullary Hematopoiesis ◽  
Hematopoietic Stem ◽  
Multipotent Progenitors ◽  
Myeloid Progenitors

Abstract Human genomic studies have identified frequent MYC amplification and copy number gains in myeloid malignancies, and previous studies have shown that MYC plays important roles in survival of Myeloproliferative Neoplasms (MPN) and Acute Myeloid Leukemia (AML) cells. Notably, our recent studies have shown that MYC impairs myeloid cell differentiation and promotes proliferation of myeloid progenitors and AML cells by controlling genomic methylation. However, it is unclear if increased levels of MYC in hematopoietic stem cells (HSCs) and myeloid progenitors is sufficient to provoke the development of MPN or AML and, if so, how this occurs. To addresses these questions we generated Mx1-Cre;Rosa26-LSL-MYC transgenic mouse model that inducibly overexpress MYC following polyinosinic:polycytidylic acid (pIpC) injection and Cre-mediated deletion of loxp-stop-loxp cassette. MYC overexpression was confirmed by qRT-PCR and immunoblot. Complete blood counts (CBC) with differential in the Mx1-Cre +/-;Rosa26-LSL-MYC +/+ mice vs. -MYC +/-or -wild type (WT) littermate mice at week 23 revealed worsening anemia (Hb, 9.6 vs. 16.3 vs. 15.5g/dL, p<0.0001), lymphopenia (73.2 vs. 84.3 vs. 84.5%, p<0.0001), and monocytosis (7.4 vs. 1.8 vs. 0.9%, p=0.0097). Also, bone marrow (BM) cells from the Mx1-Cre +/-;Rosa26-LSL-MYC +/+ mice showed increased monocyte- and granulomonocyte-colony forming potential (CFU-M and CFU-GM), but with limited self-renewal capacity ex vivo (i.e., no CFU after 5 serial plating). Further, inducible MYC overexpression promotes expansion of HSCs (Lin -Sca-1 +cKit + [LSK]), multipotent progenitors (MPPs; LSK CD48 +CD150 -), common myeloid progenitors (CMPs; Lin -Sca1 -cKit +), granulocyte-monocyte progenitors (GMPs; Lin -Sca-1 -cKit +CD34 +FCγR +), and Gr-1/CD11b+ mature myeloid cells, with concomitant reduction of B220+ or CD3+ cells in the BM and spleen. In addition, MYC overexpression provokes splenomegaly (565 vs. 150 vs. 100mg at week 18~22, p<0.0001), extramedullary hematopoiesis with markedly atypical megakaryopoiesis and myeloid preponderance akin to MPN that reduces overall survival (median OS, 157 days vs. not reached vs. not reached, p<0.0001). Collectively, these findings suggest MYC confers enhanced proliferation and survival properties to HSCs and MPPs leading to MPN-like disease. We have shown MYC oncogenic functions in AML cells requires its suppression of TFEB, an mTORC1 regulated bHLH-LZ transcription factor, and that TFEB functions as a tumor suppressor by inducing IDH1/2-TET2 signaling, thus promoting 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) conversion in key genes that drive myeloid differentiation and cell death. Similarly, inducible overexpression of MYC in the Mx1-Cre +/-;Rosa26-LSL-MYC +/+ mice significantly reduces the expression of Tfeb, Idh1 and Idh2, and 5hmC levels in both c-Kit + and Cd11b + BM cells. Further, 4-OHT-mediated silencing of Myc in ex vivo cultured BM cells from the Rosa26-CreER T2+/-;Myc fl/fl mice impairs myeloid cell proliferation and robustly induces the expression of Tfeb, Idh1, and Idh2 as well as levels of 5hmC. Finally, inducible TFEB expression in normal 32D.3 myeloid progenitor cells impairs cell proliferation and upregulates 5hmC levels, and these responses are partially reversed by treatment with 2-hydroxyglutarate, an oncometabolite that inhibits 5mC-to-5hmC conversion. Collectively, these findings suggest that the MYC-TFEB-IDH1/2 epigenetic circuit plays a pivotal role in promoting myeloid proliferation to drive the malignant transformation of HSCs to the MPN. Disclosures Kuykendall: Pharmaessentia: Honoraria; Abbvie: Honoraria; Protagonist: Consultancy, Research Funding; Incyte: Consultancy; Blueprint: Honoraria; Celgene/BMS: Honoraria; Novartis: Honoraria, Speakers Bureau. Komrokji: Agios: Honoraria, Speakers Bureau; Acceleron: Honoraria; Geron: Honoraria; Novartis: Honoraria; Abbvie: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; JAZZ: Honoraria, Speakers Bureau.

scholarly journals Calreticulin haploinsufficiency augments stem cell activity and is required for onset of myeloproliferative neoplasms

Blood ◽  
2020 ◽  
Author(s):  
Kotaro Shide ◽  
Takuro Kameda ◽  
Ayako Kamiunten ◽  
Yoshinori Ozono ◽  
Yuki Tahira ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Cell Activity ◽  
Extramedullary Hematopoiesis ◽  
The Self ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Deficient Mice

Mutations in JAK2, MPL, or CALR are detected in more than 80% of myeloproliferative neoplasm (MPN) patients and are thought to play a driver role in MPN pathogenesis via autosomal activation of the JAK-STAT signaling cascade. Mutant CALR binds to MPL, activates downstream MPL signaling cascades, and induces essential thrombocythemia in mice. However, embryonic lethality of Calr-deficient mice precludes determination of a role for CALR in hematopoiesis. To clarify the role of CALR in normal hematopoiesis and MPN pathogenesis, we generated hematopoietic cell-specific Calr-deficient mice. CALR deficiency had little effect on the leukocyte count, hemoglobin levels, or platelet count in peripheral blood. However, Calr-deficient mice showed some hematopoietic properties of MPN, including decreased erythropoiesis and increased myeloid progenitor cells in the bone marrow, and extramedullary hematopoiesis in the spleen. Transplantation experiments revealed that Calr haploinsufficiency promoted the self-renewal capacity of hematopoietic stem cells. We generated CALRdel52 mutant transgenic mice with Calr haploinsufficiency as a model that mimics human MPN patients and found that Calr haploinsufficiency restored the self-renewal capacity of hematopoietic stem cells damaged by CALR mutations. Only recipient mice transplanted with Lineage－Sca1+c-kit+ cells harboring both CALR mutation and Calr haploinsufficiency developed MPN in competitive conditions, showing that CALR haploinsufficiency was required for the onset of CALR-mutated MPNs.

Cyclical Neutropenia and Other Periodic Hematological Disorders: A Review of Mechanisms and Mathematical Models

Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2629-2640 ◽  
Author(s):  
Caroline Haurie ◽  
David C. Dale ◽  
Michael C. Mackey
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Hemolytic Anemia ◽  
Cell Loss ◽  
Myelogenous Leukemia ◽  
Hematopoietic Stem ◽  
Hematological Disorders ◽  
Regulatory Processes ◽  
Cyclical Neutropenia ◽  
Immune Hemolytic Anemia

Abstract Although all blood cells are derived from hematopoietic stem cells, the regulation of this production system is only partially understood. Negative feedback control mediated by erythropoietin and thrombopoietin regulates erythrocyte and platelet production, respectively, but the regulation of leukocyte levels is less well understood. The local regulatory mechanisms within the hematopoietic stem cells are also not well characterized at this point. Because of their dynamic character, cyclical neutropenia and other periodic hematological disorders offer a rare opportunity to more fully understand the nature of these regulatory processes. We review the salient clinical and laboratory features of cyclical neutropenia (and the less common disorders periodic chronic myelogenous leukemia, periodic auto-immune hemolytic anemia, polycythemia vera, aplastic anemia, and cyclical thrombocytopenia) and the insight into these diseases afforded by mathematical modeling. We argue that the available evidence indicates that the locus of the defect in most of these dynamic diseases is at the stem cell level (auto-immune hemolytic anemia and cyclical thrombocytopenia seem to be the exceptions). Abnormal responses to growth factors or accelerated cell loss through apoptosis may play an important role in the genesis of these disorders. © 1998 by The American Society of Hematology.

scholarly journals Clinically Relevant Gene Editing in Hematopoietic Stem Cells for the Treatment of Pyruvate Kinase Deficiency Hemolytic Anemia

2021 ◽  
Author(s):  
Sara Fañanas-Baquero ◽  
Oscar Quintana-Bustamante ◽  
Daniel P. Dever ◽  
Omaira Alberquilla ◽  
Rebeca Sanchez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Pyruvate Kinase ◽  
Hemolytic Anemia ◽  
Gene Editing ◽  
Autosomal Recessive Disorder ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
Pyruvate Kinase Deficiency ◽  
Relevant Gene

ABSTRACTPyruvate Kinase Deficiency (PKD) is an autosomal recessive disorder caused by mutations in the PKLR gene, which constitutes the main cause of chronic non-spherocytic hemolytic anemia. PKD incidence is estimated in 1 in 20,000 people worldwide. The PKLR gene encodes for the erythroid pyruvate kinase protein (RPK) implicated in the last step of the anaerobic glycolysis in red blood cells. The defective enzyme fails to maintain normal erythrocyte ATP levels, producing severe hemolytic anemia, and can be fatal in severe patients. The only curative treatment for PKD is allogeneic hematopoietic stem and progenitor cells (HSPC) transplantation, so far. However, HSPC transplant is associated with a significant morbidity and mortality, especially in PKD patients. Here, we address the correction of PKD through precise gene editing at the PKLR endogenous locus to keep the tight regulation of RPK enzyme during erythropoiesis. We combined CRISPR/Cas9 system and rAAVs for donor matrix delivery to build an efficient and safe system to knock-in a therapeutic donor at the translation start site of the RPK isoform in human hematopoietic progenitors. Edited human hematopoietic progenitors efficiently reconstituted human hematopoiesis in primary and secondary immunodeficient recipient mice. Moreover, erythroid cells derived from edited PKD-HSPCs restored normal levels of ATP, demonstrating the restoration of RPK function in PKD erythropoiesis after gene editing. Our gene editing strategy may represent a lifelong therapy to restore RPK functionality in RBCs of patients and correct PKD.Single Sentence SummaryClinically relevant gene editing in hematopoietic stem cells for the treatment of Pyruvate Kinase Deficiency.

Hematopoietic Stem Cells in the Mouse Spleen

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2421-2421 ◽  
Author(s):  
Akiko Iseki ◽  
Yohei Morita ◽  
Hiromitsu Nakauchi ◽  
Hideo Ema
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Low Frequency ◽  
Extramedullary Hematopoiesis ◽  
Spleen Cells ◽  
Hematopoietic Stem ◽  
Hematopoietic Organ ◽  
Physiological Conditions ◽  
Cell Niche

Abstract The spleen is a hematopoietic organ in mice. Hematopoietic stem cells (HSCs) migrate into the spleen around embryonic day 14, and then migrate into the bone marrow (BM) around embryonic day 17. Thereafter, HSCs reside in both BM and spleen throughout the life of a mouse. The spleen is the major site of extramedullary hematopoiesis in pathological conditions. The spleen serves as an active hematopoietic organ in lethally irradiated mice for a while after transplantation with BM cells. Osteoblasts are considered to be one of the stem cell niche components. Because there are no osteoblasts in the spleen, niches in the spleen possibly functions differently from ones in the BM. The regulation of HSCs likely differs between the BM and spleen. In order to understand a role of spleen HSCs in physiological conditions, we have characterized HSCs in the spleen as compared with those in the BM. BM and spleen cells were obtained from 8–10 week-old C57BL/6 mice. Competitive repopulation showed that the repopulating activity per 106 BM cells was significantly greater than that per 106 spleen cells (about 10-fold). Limiting analysis showed that the frequency of long-term repopulating cells in BM cells was significantly higher than that in spleen cells (about 10-fold). As a result, the mean activity per BM stem cell was similar to that per spleen stem cell. Similarly to BM, CD34-negative, c-Kit-positive, Sca-1-positive, lineage markers-negative (CD34−KSL) cells were highly enriched in HSCs in the spleen. The frequency of CD34−KSL cells in the spleen was significantly lower than that in the BM. These data indicate that functionally equivalent HSCs exist in the spleen but at a low frequency. Data from single cell-transplantation supported this notion. The proportion of pyronin Y-negative G0 cells among BM CD34−KSL cells was greater than that among spleen CD34−KSL cells at any one time. BrdU-uptake analysis showed that spleen CD34− KSL cells were cycling more rapidly than BM CD34−KSL cells. These data suggest that spleen HSCs contribute to hematopoiesis to some extent under physiological conditions. BM and spleen HSCs may be interchangeable via the circulation. When BM HSCs are in the spleen, they are possibly under the control of spleen niches different from BM niches.

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