The Hox cofactor and proto-oncogene Pbx1 is required for maintenance of definitive hematopoiesis in the fetal liver

Blood ◽  
2001 ◽  
Vol 98 (3) ◽  
pp. 618-626 ◽  
Author(s):  
Jorge F. DiMartino ◽  
Licia Selleri ◽  
David Traver ◽  
Meri T. Firpo ◽  
Joon Rhee ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Fetal Liver ◽  
Chromosomal Translocations ◽  
Severe Anemia ◽  
Hematopoietic Progenitors ◽  
Homeodomain Proteins ◽  
Acute Leukemias ◽  
Hematopoietic Stem ◽  
Definitive Hematopoiesis

Abstract Pbx1 is the product of a proto-oncogene originally discovered at the site of chromosomal translocations in acute leukemias. It binds DNA as a complex with a broad subset of homeodomain proteins, but its contributions to hematopoiesis have not been established. This paper reports that Pbx1 is expressed in hematopoietic progenitors during murine embryonic development and that its absence results in severe anemia and embryonic lethality at embryonic day 15 (E15) or E16. Definitive myeloerythroid lineages are present inPbx1−/−fetal livers, but the total numbers of colony-forming cells are substantially reduced. Fetal liver hypoplasia reflects quantitative as well as qualitative defects in the most primitive multilineage progenitors and their lineage-restricted progeny. Hematopoietic stem cells from Pbx1−/−embryos have reduced colony-forming activity and are unable to establish multilineage hematopoiesis in competitive reconstitution experiments. Common myeloid progenitors (CMPs), the earliest known myeloerythroid-restricted progenitors, are markedly depleted inPbx1−/−embryos at E14 and display clonogenic defects in erythroid colony formation. Comparative cell-cycle indexes suggest that these defects result largely from insufficient proliferation. Megakaryocyte- and erythrocyte-committed progenitors are also reduced in number and show decreased erythroid colony-forming potential. Taken together, these data indicate that Pbx1 is essential for the function of hematopoietic progenitors with erythropoietic potential and that its loss creates a proliferative constriction at the level of the CMP. Thus, Pbx1 is required for the maintenance, but not the initiation, of definitive hematopoiesis and contributes to the mitotic amplifications of progenitor subsets through which mature erythrocytes are generated.

Expression of CD41 marks the initiation of definitive hematopoiesis in the mouse embryo

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 508-516 ◽  
Author(s):  
Hanna K. A. Mikkola ◽  
Yuko Fujiwara ◽  
Thorsten M. Schlaeger ◽  
David Traver ◽  
Stuart H. Orkin
Keyword(s):  
Endothelial Cells ◽  
Mouse Embryo ◽  
Fetal Liver ◽  
Stem Cell Differentiation ◽  
Yolk Sac ◽  
Embryoid Bodies ◽  
Embryonic Stem Cell Differentiation ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
Definitive Hematopoiesis

Murine hematopoietic stem cells (HSCs) originate from mesoderm in a process that requires the transcription factor SCL/Tal1. To define steps in the commitment to blood cell fate, we compared wild-type and SCL−/− embryonic stem cell differentiation in vitro and identified CD41 (GpIIb) as the earliest surface marker missing from SCL−/− embryoid bodies (EBs). Culture of fluorescence-activated cell sorter (FACS) purified cells from EBs showed that definitive hematopoietic progenitors were highly enriched in the CD41+ fraction, whereas endothelial cells developed from CD41− cells. In the mouse embryo, expression of CD41 was detected in yolk sac blood islands and in fetal liver. In yolk sac and EBs, the panhematopoietic marker CD45 appeared in a subpopulation of CD41+ cells. However, multilineage hematopoietic colonies developed not only from CD45+CD41+ cells but also from CD45−CD41+ cells, suggesting that CD41 rather than CD45 marks the definitive culture colony-forming unit (CFU-C) at the embryonic stage. In contrast, fetal liver CFU-C was CD45+, and only a subfraction expressed CD41, demonstrating down-regulation of CD41 by the fetal liver stage. In yolk sac and EBs, CD41 was coexpressed with embryonic HSC markers c-kit and CD34. Sorting for CD41 and c-kit expression resulted in enrichment of definitive hematopoietic progenitors. Furthermore, the CD41+c-kit+ population was missing from runx1/AML1−/− EBs that lack definitive hematopoiesis. These results suggest that the expression of CD41, a candidate target gene of SCL/Tal1, and c-kit define the divergence of definitive hematopoiesis from endothelial cells during development. Although CD41 is commonly referred to as megakaryocyte–platelet integrin in adult hematopoiesis, these results implicate a wider role for CD41 during murine ontogeny.

Hoxb4-deficient mice undergo normal hematopoietic development but exhibit a mild proliferation defect in hematopoietic stem cells

Blood ◽  
2004 ◽  
Vol 103 (11) ◽  
pp. 4126-4133 ◽  
Author(s):  
Ann C. M. Brun ◽  
Jon Mar Björnsson ◽  
Mattias Magnusson ◽  
Nina Larsson ◽  
Per Leveén ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Hox Genes ◽  
Fetal Liver ◽  
Severe Combined Immunodeficiency ◽  
Hematopoietic Stem ◽  
Cell Counts ◽  
Mild Reduction

Abstract Enforced expression of Hoxb4 dramatically increases the regeneration of murine hematopoietic stem cells (HSCs) after transplantation and enhances the repopulation ability of human severe combined immunodeficiency (SCID) repopulating cells. Therefore, we asked what physiologic role Hoxb4 has in hematopoiesis. A novel mouse model lacking the entire Hoxb4 gene exhibits significantly reduced cellularity in spleen and bone marrow (BM) and a subtle reduction in red blood cell counts and hemoglobin values. A mild reduction was observed in the numbers of primitive progenitors and stem cells in adult BM and fetal liver, whereas lineage distribution was normal. Although the cell cycle kinetics of primitive progenitors was normal during endogenous hematopoiesis, defects in proliferative responses of BM Lin- Sca1+ c-kit+ stem and progenitor cells were observed in culture and in vivo after the transplantation of BM and fetal liver HSCs. Quantitative analysis of mRNA from fetal liver revealed that a deficiency of Hoxb4 alone changed the expression levels of several other Hox genes and of genes involved in cell cycle regulation. In summary, the deficiency of Hoxb4 leads to hypocellularity in hematopoietic organs and impaired proliferative capacity. However, Hoxb4 is not required for the generation of HSCs or the maintenance of steady state hematopoiesis.

scholarly journals Functional heterogeneity is associated with the cell cycle status of murine hematopoietic stem cells

1993 ◽  
Vol 122 (4) ◽  
pp. 897-902 ◽  
Author(s):  
WH Fleming ◽  
EJ Alpern ◽  
N Uchida ◽  
K Ikuta ◽  
GJ Spangrude ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Significant Proportion ◽  
Cell Activity ◽  
Rhodamine 123 ◽  
Hematopoietic Stem ◽  
Cell Cycle Status

Hematopoietic stem cells (HSCs) are characterized by their ability to differentiate into all hematopoietic cell lineages while retaining their capacity for self renewal. One of the predictions of this model is the existence of a heterogeneous pool of HSCs, some members of which are destined to become lineage restricted progenitor cells while others function to renew the stem cell pool. To test whether HSCs are heterogeneous with respect to cell cycle status, we determined the fraction of phenotypically defined murine HSCs (Thy1.1lo Lin-/lo Sca-1+) that contain > 2n amount of DNA as measured by propidium iodide staining, Hoechst dye uptake and [3H]thymidine labeling; that fraction is 18-22%. In contrast, in the developing fetal liver, 40% of HSCs are in the S/G2/M phases of the cell cycle. Those HSCs which exhibit a low level of staining with rhodamine 123 are almost exclusively in G0/G1 (97%) whereas only 70% of HSCs which stain brightly for rhodamine 123 are in G0/G1. The injection of 100 G0/G1 HSCs rescued 90% of lethally irradiated mice in contrast to 100 S/G2/M HSCs, which protected only 25% of lethally irradiated recipients. Enhanced long-term donor-derived multilineage reconstitution of the peripheral blood was observed in recipients of 100 G0/G1 HSCs compared to recipients of 100 S/G2/M cells. These data indicate that a significant proportion of HSCs are actively proliferating during steady state hematopoiesis and that this subpopulation of cells exhibits reduced stem cell activity.

scholarly journals Targeted disruption of Zfp36l2, encoding a CCCH tandem zinc finger RNA-binding protein, results in defective hematopoiesis

Blood ◽  
2009 ◽  
Vol 114 (12) ◽  
pp. 2401-2410 ◽  
Author(s):  
Deborah J. Stumpo ◽  
Hal E. Broxmeyer ◽  
Toni Ward ◽  
Scott Cooper ◽  
Giao Hangoc ◽  
...  
Keyword(s):  
Rna Binding ◽  
Fetal Liver ◽  
Early Embryo ◽  
Hematopoietic Progenitors ◽  
Targeted Disruption ◽  
Hematopoietic Stem ◽  
Subsequent Degradation ◽  
Stem And Progenitor Cells ◽  
Partial Deficiency ◽  
Definitive Hematopoiesis

Abstract Members of the tristetraprolin family of tandem CCCH finger proteins can bind to AU-rich elements in the 3′-untranslated region of mRNAs, leading to their deadenylation and subsequent degradation. Partial deficiency of 1 of the 4 mouse tristetraprolin family members, Zfp36l2, resulted in complete female infertility because of early embryo death. We have now generated mice completely deficient in the ZFP36L2 protein. Homozygous Zfp36l2 knockout (KO) mice died within approximately 2 weeks of birth, apparently from intestinal or other hemorrhage. Analysis of peripheral blood from KO mice showed a decrease in red and white cells, hemoglobin, hematocrit, and platelets. Yolk sacs from embryonic day 11.5 (E11.5) Zfp36l2 KO mice and fetal livers from E14.5 KO mice gave rise to markedly reduced numbers of definitive multilineage and lineage-committed hematopoietic progenitors. Competitive reconstitution experiments demonstrated that Zfp36l2 KO fetal liver hematopoietic stem cells were unable to adequately reconstitute the hematopoietic system of lethally irradiated recipients. These data establish Zfp36l2 as a critical modulator of definitive hematopoiesis and suggest a novel regulatory pathway involving control of mRNA stability in the life cycle of hematopoietic stem and progenitor cells.

Podocalyxin is a CD34-related marker of murine hematopoietic stem cells and embryonic erythroid cells

Blood ◽  
2005 ◽  
Vol 105 (11) ◽  
pp. 4170-4178 ◽  
Author(s):  
Regis Doyonnas ◽  
Julie S. Nielsen ◽  
Shierley Chelliah ◽  
Erin Drew ◽  
Takahiko Hara ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Erythroid Cells ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
Nucleated Red Blood Cells ◽  
Erythroid Precursors ◽  
Valuable Marker

Abstract Podocalyxin/podocalyxin-like protein 1 [PCLP1]/thrombomucin/MEP21 is a CD34-related sialomucin. We have performed a detailed analysis of its expression during murine development and assessed its utility as a marker of hematopoietic stem cells (HSCs) and their more differentiated progeny. We find that podocalyxin is highly expressed by the first primitive hematopoietic progenitors and nucleated red blood cells to form in the embryonic yolk sac. Likewise, podocalyxin is expressed by definitive multilineage hematopoietic progenitors and erythroid precursors in fetal liver. The level of podocalyxin expression gradually declines with further embryo maturation and reaches near-background levels at birth. This is followed by a postnatal burst of expression that correlates with the seeding of new hematopoietic progenitors to the spleen and bone marrow. Shortly thereafter, podocalyxin expression gradually declines, and by 4 weeks postpartum it is restricted to a rare population of Sca-1+, c-kit+, lineage marker- (Lin-) cells in the bone marrow. These rare podocalyxin-expressing cells are capable of serially reconstituting myeloid and lymphoid lineages in lethally irradiated recipients, suggesting they have HSC activity. In summary, we find that podocalyxin is a marker of embryonic HSCs and erythroid cells and of adult HSCs and that it may be a valuable marker for the purification of these cells for transplantation.

Rb Plays an Essential Role in Erythroid Differentiation through Inhibition of Apoptosis Mediated by NFKB.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 308-308
Author(s):  
Sahoko Matsuoka ◽  
Atsushi Hirao ◽  
Fumio Arai ◽  
Keiyo Takubo ◽  
Kana Miyamoto ◽  
...  
Keyword(s):  
Essential Role ◽  
Molecular Mechanisms ◽  
Fetal Liver ◽  
Erythroid Differentiation ◽  
Severe Anemia ◽  
Cell Surface Markers ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
Rb Gene ◽  
Terminal Erythroid Differentiation

Abstract Inactivation of the retinoblastoma (Rb) gene results in embryonic lethality due to severe anemia and increased nucleated erythrocytes by day14. However, molecular mechanisms of the function of Rb in erythroid differentiation have been unclear. Recent studies have suggested that Rb has both intrinsic and extrinsic roles on erythroid differentiation. Using Rb-deficient (Rb−/−) embryos(E12), we showed that Rb regulates terminal erythroid differentiation through inhibition of apoptosis mediated by NFKB. Enucleation of erythroblasts was impaired in semisolid culture of Rb−/− hematopoietic progenitors in fetal liver. The lethally-irradiated recipient mice transplanted with Rb−/− hematopoietic stem cells (HSCs) showed severe anemia with splenomegaly, whereas the number of leukocytes and platelets were normal. In Rb−/− recipient mice, the nucleated erythrocytes and reticulocytes were significantly increased in the peripheral blood. We analyzed cell surface markers for erythroid lineage (TER119 and CD71) in the enlarged spleen. A block of erythroid differentiation at the early erythroblast stage (TER119high CD71high), accompanied with increased apoptosis, was observed in the recipient mice with Rb−/− HSCs. We speculated that the defect in the erythroid differentiation of Rb−/− HSCs might be caused by inappropriate cell death. Thus, we examined expression of apoptosis-related genes in early erythroblasts (CD71high Ter119high) and observed decrease of Bcl-XL expression. To clarify the function of Bcl-XL, we introduced exogenous cDNA of mouse Bcl-XL with GFP (Bcl-XL ires GFP) or GFP alone as control into HSCs and then transplanted them to lethally irradiated mice. From the point of CD71 and Ter119 expression pattern in GFP positive cells, Rb−/− erythoblasts still showed the block in differentiation. In contrast, overexpression of Bcl-XL in Rb−/− erythoblasts inhibited inappropriated apoptosis and restore the differentiation capacity. Further, we found that inactivation of NFKB, but not STAT5 in Rb−/− erythroblasts. Treatment of NFKB inhibitor suppressed erythroid differentiation, accompanied by enucleation, and also inhibited upregulation of Bcl-XL. These data demonstrates that Rb is essential for erythroid differentiation through inhibition of apoptosis mediated by NFKB.

scholarly journals Cellular Basis of Embryonic Hematopoiesis and Its Implications in Prenatal Erythropoiesis

2020 ◽  
Vol 21 (24) ◽  
pp. 9346
Author(s):  
Toshiyuki Yamane
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Yolk Sac ◽  
Hematopoietic Progenitors ◽  
Adult Type ◽  
Hematopoietic Stem ◽  
Cellular Origin ◽  
Developmental Switches ◽  
Primitive Erythropoiesis

Primitive erythrocytes are the first hematopoietic cells observed during ontogeny and are produced specifically in the yolk sac. Primitive erythrocytes express distinct hemoglobins compared with adult erythrocytes and circulate in the blood in the nucleated form. Hematopoietic stem cells produce adult-type (so-called definitive) erythrocytes. However, hematopoietic stem cells do not appear until the late embryonic/early fetal stage. Recent studies have shown that diverse types of hematopoietic progenitors are present in the yolk sac as well as primitive erythroblasts. Multipotent hematopoietic progenitors that arose in the yolk sac before hematopoietic stem cells emerged likely fill the gap between primitive erythropoiesis and hematopoietic stem-cell-originated definitive erythropoiesis and hematopoiesis. In this review, we discuss the cellular origin of primitive erythropoiesis in the yolk sac and definitive hematopoiesis in the fetal liver. We also describe mechanisms for developmental switches that occur during embryonic and fetal erythropoiesis and hematopoiesis, particularly focusing on recent studies performed in mice.

scholarly journals The Ets2 Repressor Factor (Erf) Is Required for Effective Primitive and Definitive Hematopoiesis

2017 ◽  
Vol 37 (19) ◽  
Author(s):  
Ioanna Peraki ◽  
James Palis ◽  
George Mavrothalassitis
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Blood Cells ◽  
Fetal Liver ◽  
Normal Function ◽  
Severe Anemia ◽  
Hematopoietic Stem ◽  
Stem Cell Maintenance ◽  
Definitive Hematopoiesis ◽  
Cell Maintenance

ABSTRACT Erf is a gene for a ubiquitously expressed Ets DNA-binding domain-containing transcriptional repressor. Erf haploinsufficiency causes craniosynostosis in humans and mice, while its absence in mice leads to failed chorioallantoic fusion and death at embryonic day 10.5 (E10.5). In this study, we show that Erf is required in all three waves of embryonic hematopoiesis. Mice lacking Erf in the embryo proper exhibited severe anemia and died around embryonic day 14.5. Erf epiblast-specific knockout embryos had reduced numbers of circulating blood cells from E9.5 onwards, with the development of severe anemia by E14.5. Elimination of Erf resulted in both reduced and more immature primitive erythroblasts at E9.5 to E10.5. Reduced definitive erythroid colony-forming activity was found in the bloodstream of E10.5 embryos and in the fetal liver at E11.5 to E13.5. Finally, elimination of Erf resulted in impaired repopulation ability, indicating that Erf is necessary for hematopoietic stem cell maintenance or differentiation. We conclude that Erf is required for both primitive and erythromyeloid progenitor waves of hematopoietic stem cell (HSC)-independent hematopoiesis as well as for the normal function of HSCs.

scholarly journals Hemogenic endothelium during development and beyond

Blood ◽  
2012 ◽  
Vol 119 (21) ◽  
pp. 4823-4827 ◽  
Author(s):  
Karen K. Hirschi
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Endothelial Cells ◽  
Blood Cell ◽  
Fetal Liver ◽  
Hemogenic Endothelium ◽  
Hematopoietic Stem ◽  
Adult Bone ◽  
Definitive Hematopoiesis ◽  
Yolk Sac Placenta

Abstract During embryonic development, multilineage HSCs/progenitor cells are derived from specialized endothelial cells, termed hemogenic endothelium, within the yolk sac, placenta, and aorta. Whether hemogenic endothelial cells contribute to blood cell development at other sites of definitive hematopoiesis, such as in the fetal liver and fetal bone marrow, is not known. Also unknown is whether such cells exist within the vasculature of adult bone marrow and generate hematopoietic stem cells after birth. These issues and their clinical relevance are discussed herein.

Cyclin A2 Plays a Critical Role in Proliferation of Lymphoid Progenitors

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 914-914
Author(s):  
Kentaro Kohno ◽  
Hiromi Iwasaki ◽  
Tadafumi Iino ◽  
Shin-ichi Mizuno ◽  
Peter Sicinski ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
B Cell ◽  
Progenitor Cells ◽  
Critical Role ◽  
Embryonic Stem ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
M Phase ◽  
Cyclin A2

Abstract Abstract 914 Cell cycle regulators could be differentially used among self–renewing stem cells, rapidly expanding progenitor cells, and terminally differentiated cells those clonally replicate. Cyclin A is a regulatory subunit for cyclin dependent kinase (Cdk) 1 and Cdk2, and it drives S phase progression as well as transition to G2/M phase in cell cycle. We have previously reported that cyclin A2 is not required for fibroblast replication but it is indispensable in maintenance of self-renewing stem cells, including embryonic stem cells and hematopoietic stem cells (HSCs) (Cell 138 2009). The question is whether cyclin A2 plays a role in proliferation of hematopoietic progenitors downstream of the HSC. Here, we further assessed the requirement of cyclin A2 in non-self-renewing hematopoietic progenitors. Quantitative RT-PCR analysis showed that cyclin A2 was expressed in hematopoietic progenitor cells as well as stem cells, and its expression level is highest in lymphoid-committed progenitor stages of both T and B cell lineages. Thus, in order to test the role of cylin A2 in early lymphopoiesis, we crossed cyclin A2 floxed mice with Rag1-Cre knock-in mice. Because recombination activating gene (RAG)-1 is essential for generation of pre-BCRs and pre-TCRs that are critical for expansion of B and T lymphoid progenitor cells, respectively, we hypothesized that the requirement of Cyclin A2 in early lymphopoiesis can be assessed in this system. As we expected, the Rag1-Cre cyclin A2 floxed/floxed mice were viable, and have normal numbers of HSCs and myeloid progenitors. They, however, displayed severe reduction of mature T and B cell numbers that were only 1/100 - 1/10 of wild-type controls. The number of common lymphoid progenitor was unchanged, but there were severely reduced preB cells in bone marrow and T cell progenitors from CD4-CD8- double negative stage in thymus. Furthermore, cell cycle analysis shows that the Cyclin A2 disrupted progenitors are unable to progress from S to G2/M phase, and in vitro culture clearly showed that those progenitors are unable to proliferate and resulted in apoptosis. These findings clearly demonstrate that cyclin A2 is indispensable not only for self-renewing HSCs, but also for proliferation of T and B cell progenitors. Disclosures: No relevant conflicts of interest to declare.

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