scholarly journals Stat3 Is Activated By ROS to Uniquely Regulate Primitive Erythropoiesis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2216-2216
Author(s):  
Zachary C. Murphy ◽  
Kathleen E. McGrath ◽  
James Palis
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Cycle Progression ◽  
Fetal Liver ◽  
Yolk Sac ◽  
Erythroid Cells ◽  
Erythroid Progenitors ◽  
Mammalian Embryo ◽  
Stat3 Phosphorylation ◽  
Murine Embryo ◽  
Primitive Erythropoiesis

The mammalian embryo requires the sequential circulation of primitive and definitive erythroid cells for survival and growth. The central cytokine regulator of primitive and definitive erythropoiesis is erythropoietin (EPO). We have previously determined that primitive erythroid progenitors, unlike their definitive (CFU-E) counterparts, do not require EPO for survival. However, the mechanisms regulating the EPO-independent emergence of primitive erythropoiesis in the yolk sac remains poorly understood. Interestingly, maturing primitive erythroblasts in the murine embryo, unlike definitive erythroblasts in the fetal liver and adult bone marrow, express not only STAT5 but also STAT3, which is tyrosine phosphorylated at baseline and in response to EPO. These initial findings led is to hypothesize that STATs 5 and 3 differentially regulate terminal differentiation of primitive erythroid cells. To analyze the function of these two STATs in primary erythroid cells, we developed an imaging flow cytometry-based methodology to quantitate total and phosphorylated levels of STAT proteins in small numbers of cells isolated from staged murine embryos. We found that STAT5 plays conserved roles in primitive and definitive erythroblast survival and surface CD71 expression. In contrast, STAT3 regulates cell cycle progression and mitochondrial polarization specifically in primitive erythroblasts. In addition, STAT3, unlike STAT5, was phosphorylated in the absence of cytokine stimulation. We asked if reactive oxygen species (ROS) may be activating STAT3, since primary primitive erythroblasts, unlike definitive erythroblasts, specifically express Aquaporins 3 and 8, which can transport hydrogen peroxide, as well as water. Indeed, hydrogen peroxide exposure increased endogenous ROS, as well as phosphorylated STAT3, levels both in wild-type and EPOR-null primitive erythroblasts. Consistent with these findings, inhibition of aquaporin channel transport prevented STAT3 phosphorylation by exogenous hydrogen peroxide, but not by EPO. Taken together, our data support the concept that the primitive erythroid lineage, emerging in the hypoxic and EPO-low environment of the yolk sac in the pre-circulation murine embryo, uniquely integrates ROS-mediated STAT3 activation to regulate key aspects of terminal erythroid maturation. Disclosures Palis: Rubies Therapeutics: Consultancy.

Diverse Myeloid Lineage Potential Arises in the Yolk Sac of the Mammalian Embryo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1666-1666
Author(s):  
James Palis ◽  
Anne Koniski ◽  
Timothy P. Bushnell ◽  
Kathleen E. McGrath
Keyword(s):  
Fetal Liver ◽  
Yolk Sac ◽  
Erythroid Progenitors ◽  
Mammalian Embryo ◽  
Gm Csf ◽  
Gamma Receptor ◽  
Broad Array ◽  
Murine Embryo ◽  
Temporal And Spatial ◽  
Definitive Hematopoiesis

Abstract The emergence of the hematopoietic system in the mammalian embryo is characterized by two temporally overlapping waves of distinct “primitive” and “definitive” erythroid progenitors that peak in the murine yolk sac at E8.5 and E10.5, respectively. We have recently determined that each wave contains megakaryocyte potential (Tober, et al., submitted), but the initial emergence of distinct myeloid lineages is less well understood. Temporal and spatial analysis of hematopoietic progenitors in the murine embryo suggest that the macrophage lineage is associated with both waves, while neutrophil and mast cell lineages are restricted to the second, definitive wave (Palis, et al., Development126:5073, 1999). To better define the emergence of myelopoiesis in the murine embryo, we cultured dissociated E9.5 yolk sac cells in a broad array of cytokines (SCF, IL3, IL5, IL6, IL7, IL9, IL11 and GM-CSF) for seven days and identified morphologically distinguishable macrophages, neutrophils, eosinophils, basophils, and mast cells. The presence of eosinophils was further confirmed by expression of eosinophil peroxidase transcripts. As expected, this multilineage myeloid potential was restricted to c-kit++ cells. However, unlike the bone marrow, these c-kit++ cells in the E9.5 yolk sac were predominately a single population that also express CD41 and Fc gamma receptor (FcγR, CD16/32). FcγR+ cells first emerge in the yolk sac between E8.5 and E9.5 and are not found in the embryo proper until E10.5, when they are restricted to the liver. These findings suggest that the expression of FcγR is restricted in the yolk sac to definitive hematopoiesis and tracks its transition to the fetal liver. While mature definitive erythroid cells first emerge from the fetal liver at E12.5, to our knowledge the onset of granulopoiesis has not been investigated in the early murine embryo. We found approximately 1000 GR1+/Mac1+ cells in the fetal liver at E12.5 and this population expands 100-fold during the next two days of development. These GR1+/Mac1+ cells consisted predominantly of progressively maturing neutrophils. We conclude that the potential to generate multiple myeloid lineages first arises in the yolk sac along with definitive erythroid progenitors and that a robust granulocyte population subsequently emerges in the fetal liver at midgestation.

“Definitive” Erythropoiesis Has Distinct Developmental Origins and Globin Expression Patterns in the Mammalian Embryo.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2539-2539
Author(s):  
Kathleen E. McGrath ◽  
Jenna M Frame ◽  
George Fromm ◽  
Anne D Koniski ◽  
Paul D Kingsley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fetal Liver ◽  
Globin Gene ◽  
Yolk Sac ◽  
Globin Genes ◽  
Beta Globin ◽  
Erythroid Cells ◽  
Erythroid Progenitors ◽  
Low Levels ◽  
Globin Gene Expression

Abstract Abstract 2539 Poster Board II-516 A transient wave of primitive erythropoiesis begins at embryonic day 7.5 (E7.5) in the mouse as yolk sac-derived primitive erythroid progenitors (EryP-CFC) generate precursors that mature in the circulation and expand in numbers until E12.5. A second wave of erythroid progenitors (BFU-E) originates in the yolk sac beginning at E8.25 that generate definitive erythroid cells in vitro. These BFU-E colonize the newly forming liver beginning at E10.5, prior to the initial appearance there of adult-repopulating hematopoietic stem cells (HSCs) between E11.5-12.5. This wave of definitive erythroid yolk sac progenitors is proposed to be the source of new blood cells required by the growing embryo after the expansion of primitive erythroid cells has ceased and before HSC-derived hematopoiesis can fulfill the erythropoietic needs of the embryo. We utilized multispectral imaging flow cytometry both to distinguish erythroid lineages and to define specific stages of erythroid precursor maturation in the mouse embryo. Consistent with this model, we found that small numbers of definitive erythrocytes first enter the embryonic circulation beginning at E11.5. All maturational stages of erythroid precursors were observed in the E11.5 liver, consistent with these first definitive erythrocytes having rapidly completed their maturation in the liver. The expression of βH1 and εy-beta globin genes is thought to be limited to primitive erythroid cells. Surprisingly, examination of globin gene expression by in situ hybridization revealed high levels of βH1-, but not εy-globin, transcripts in the parenchyma of E11.5-12.5 livers. RT-PCR analysis of globin mRNAs confirmed the expression of βH1- and adult β1-, but not εy-globin, in E11.5 liver-derived definitive (ckit+, Ter119lo) proerythroblasts sorted by flow cytometry to remove contaminating primitive (ckit-, Ter119+) erythroid cells. A similar pattern of globin gene expression was found in individual definitive erythroid colonies derived from E9.5 yolk sac and from early fetal liver. In vitro differentiation of definitive erythroid progenitors from E9.5 yolk sac revealed a maturational “switch” from βH1- and β1-globins to predominantly β1-globin. βH1-globin transcripts were not observed in proerythroblasts from bone marrow or E16.5 liver or in erythroid colonies from later fetal liver. ChIP analysis revealed that hyperacetylated domains encompass all beta globin genes in primitive erythroid cells but only the adult β1- and β2-globin genes in E16.5 liver proerythroblasts. Consistent with their unique gene expression, E11.5 liver proerythroblasts have hyperacetylated domains encompassing the βh1-, β1- and β2-, but not εy-globin genes. We also examined human globin transgene expression in mice carrying a single copy of the human beta globin locus. Because of the overlapping presence and changing proportion of primitive and definitive erythroid cells during development, we analyzed sorted cell populations whose identities were confirmed by murine globin gene expression. We confirmed that primitive erythroid cells express higher levels of γ- than ε-globin and little β-globin. E11.5 proerythroblasts and cultured E9.5 progenitors express γ- and β-, but not ε-globin. E16.5 liver proerythroblasts express β- and low levels of γ-globin, while adult marrow proerythroblasts express only β-globin transcripts. In summary, two forms of definitive erythropoiesis emerge in the murine embryo, each with distinct globin expression patterns and chromatin modifications of the β-globin locus. While both lineages predominantly express adult globins, the first, yolk sac-derived lineage uniquely expresses low levels of the embryonic βH1-globin gene as well as the human γ-globin transgene. The second definitive erythroid lineage, found in the later fetal liver and postnatal marrow, expresses only adult murine globins as well as low levels of the human γ-globin transgene only in the fetus. Our studies reveal a surprising complexity to the ontogeny of erythropoiesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The megakaryocyte lineage originates from hemangioblast precursors and is an integral component both of primitive and of definitive hematopoiesis

Blood ◽  
2006 ◽  
Vol 109 (4) ◽  
pp. 1433-1441 ◽  
Author(s):  
Joanna Tober ◽  
Anne Koniski ◽  
Kathleen E. McGrath ◽  
Radhika Vemishetti ◽  
Rachael Emerson ◽  
...  
Keyword(s):  
Fetal Liver ◽  
Immunohistochemical Analysis ◽  
Yolk Sac ◽  
Erythroid Progenitors ◽  
Developmental Origin ◽  
Reticulated Platelets ◽  
Primitive Hematopoiesis ◽  
Murine Embryo ◽  
Definitive Hematopoiesis ◽  
Megakaryocyte Progenitors

Abstract In the adult, platelets are derived from unipotential megakaryocyte colony-forming cells (Meg-CFCs) that arise from bipotential megakaryocyte/erythroid progenitors (MEPs). To better define the developmental origin of the megakaryocyte lineage, several aspects of megakaryopoiesis, including progenitors, maturing megakaryocytes, and circulating platelets, were examined in the murine embryo. We found that a majority of hemangioblast precursors during early gastrulation contains megakaryocyte potential. Combining progenitor assays with immunohistochemical analysis, we identified 2 waves of MEPs in the yolk sac associated with the primitive and definitive erythroid lineages. Primitive MEPs emerge at E7.25 along with megakaryocyte and primitive erythroid progenitors, indicating that primitive hematopoiesis is bilineage in nature. Subsequently, definitive MEPs expand in the yolk sac with Meg-CFCs and definitive erythroid progenitors. The first GP1bβ-positive cells in the conceptus were identified in the yolk sac at E9.5, while large, highly reticulated platelets were detected in the embryonic bloodstream beginning at E10.5. At this time, the number of megakaryocyte progenitors begins to decline in the yolk sac and expand in the fetal liver. We conclude that the megakaryocyte lineage initially originates from hemangioblast precursors during early gastrulation and is closely associated both with primitive and with definitive erythroid lineages in the yolk sac prior to the transition of hematopoiesis to intraembryonic sites.

The Megakaryocyte Lineage Arises in the Yolk Sac and Generates an Initial Wave of Large Embryonic Platelets in the Early Mammalian Embryo.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 566-566
Author(s):  
James Palis ◽  
Joanna Tober ◽  
Radhika Vemishetti ◽  
Anne Koniski ◽  
Richard Waugh
Keyword(s):  
Mouse Embryo ◽  
Fetal Liver ◽  
Primitive Streak ◽  
Yolk Sac ◽  
Erythroid Progenitors ◽  
Mammalian Embryo ◽  
Hematopoietic Organ ◽  
Adult Mice ◽  
Early Mammalian Embryo ◽  
Megakaryocyte Progenitors

Abstract Two distinct waves of hematopoietic progenitors originate in the yolk sac of the mammalian embryo. The first “primitive” wave contains primitive erythroid and macrophage progenitors that generate the embryo’s first red cells (Palis, et al. Development126:5073, 1999). The second “definitive” wave consists of definitive erythroid (BFU-E) and multiple myeloid progenitors that arise later in the yolk sac and are subsequently found in the fetal liver and postnatal marrow. While megakaryocyte progenitors have been detected in the yolk sac, the ontogeny of the megakaryocyte lineage is poorly understood. Furthermore, it is not been determined when platelets first enter the bloodstream of the mouse embryo. The presence and size of platelets in the embryonic bloodstream were examined by microscopy after staining with anti-GPV antibodies. Rare platelets were identified in 2 of 4 litters of mice at E10.5. These platelets were very large with a diameter of 4.2 ± 0.4 (mean ± SEM) microns. Platelet size remained large (4.0-3.8 microns) at E11.5–E12.5, but decreased to 3.3-3.2 microns in diameter between E13.5 and E15.5 of gestation. At birth, the mean platelet diameter (2.8 ± 0.04 microns) was similar to that of adult mice (2.7 microns). These results indicate that large, embryonic platelets begin to circulate in the mouse embryo beginning at E10.5 and raise the possibility that embryonic, fetal, and adult waves of platelets are produced during mammalian embryogenesis. Using a collagen-based culture system, megakaryocyte progenitors (Meg-CFC) were first identified in late primitive streak embryos (E7.25), concomitant with primitive erythroid progenitors. Meg-CFC numbers subsequently expand in the yolk sac along with BFU-E before the development of the fetal liver. To examine the relationship of the megakaryocyte and primitive erythroid lineages in the yolk sac, we stained hematopoietic colonies grown in collagen for 5–10 days with anti-GP1bβ (megakaryocyte) and anti-βH1-globin (primitive erythroid) antibodies. As expected, the majority of the stained colonies were primitive erythroid (containing only βH1-globin-positive cells) and approximately 15% of the colonies were megakaryocyte (containing only GP1bβ-positive cells). However, 15% of the colonies contained both GP1bβ- and βH1-globin-positive cells consistent with an origin from bipotential primitive erythroid/megakaryocyte progenitors. Furthermore, proplatelet formation was evident in both unipotential and bipotential megakaryocyte colonies cultured for 10 days. Our studies support the concept that the megakaryocyte and primitive erythroid lineages originate in the yolk sac from a bipotential precursor. This parallels lineage relationships in the bone marrow which contains bipotential definitive erythroid/megakaryocyte progenitors. Finally, we hypothesize that yolk sac-derived “primitive” Meg-CFC give rise to the first embryonic platelets that enter the bloodstream soon after the onset of circulation as the fetal liver becomes a hematopoietic organ.

Development of erythroid and myeloid progenitors in the yolk sac and embryo proper of the mouse

Development ◽  
1999 ◽  
Vol 126 (22) ◽  
pp. 5073-5084 ◽  
Author(s):  
J. Palis ◽  
S. Robertson ◽  
M. Kennedy ◽  
C. Wall ◽  
G. Keller
Keyword(s):  
Embryonic Development ◽  
Fetal Liver ◽  
Primitive Streak ◽  
Yolk Sac ◽  
Embryonic Cells ◽  
Hematopoietic Progenitors ◽  
Erythroid Progenitors ◽  
Transient Nature ◽  
Primitive Erythropoiesis ◽  
Hematopoietic Activity

In this study, we have mapped the onset of hematopoietic development in the mouse embryo using colony-forming progenitor assays and PCR-based gene expression analysis. With this approach, we demonstrate that commitment of embryonic cells to hematopoietic fates begins in proximal regions of the egg cylinder at the mid-primitive streak stage (E7.0) with the simultaneous appearance of primitive erythroid and macrophage progenitors. Development of these progenitors was associated with the expression of SCL/tal-1 and GATA-1, genes known to be involved in the development and maturation of the hematopoietic system. Kinetic analysis revealed the transient nature of the primitive erythroid lineage, as progenitors increased in number in the developing yolk sac until early somite-pair stages of development (E8.25) and then declined sharply to undetectable levels by 20 somite pairs (E9.0). Primitive erythroid progenitors were not detected in any other tissue at any stage of embryonic development. The early wave of primitive erythropoiesis was followed by the appearance of definitive erythroid progenitors (BFU-E) that were first detectable at 1–7 somite pairs (E8.25) exclusively within the yolk sac. The appearance of BFU-E was followed by the development of later stage definitive erythroid (CFU-E), mast cell and bipotential granulocyte/macrophage progenitors in the yolk sac. C-myb, a gene essential for definitive hematopoiesis, was expressed at low levels in the yolk sac just prior to and during the early development of these definitive erythroid progenitors. All hematopoietic activity was localized to the yolk sac until circulation was established (E8.5) at which time progenitors from all lineages were detected in the bloodstream and subsequently in the fetal liver following its development. This pattern of development suggests that definitive hematopoietic progenitors arise in the yolk sac, migrate through the bloodstream and seed the fetal liver to rapidly initiate the first phase of intraembryonic hematopoiesis. Together, these findings demonstrate that commitment to hematopoietic fates begins in early gastrulation, that the yolk sac is the only site of primitive erythropoiesis and that the yolk sac serves as the first source of definitive hematopoietic progenitors during embryonic development.

E26 leukemia virus converts primitive erythroid cells into cycling multilineage progenitors

Blood ◽  
2003 ◽  
Vol 101 (3) ◽  
pp. 1103-1110 ◽  
Author(s):  
Kelly M. McNagny ◽  
Thomas Graf
Keyword(s):  
Leukemia Virus ◽  
Yolk Sac ◽  
Erythroid Cells ◽  
Multilineage Differentiation ◽  
Cell Type ◽  
Hematopoietic Progenitors ◽  
Cell Type Specificity ◽  
Erythroid Progenitors ◽  
Avian Erythroblastosis Virus

Abstract Acute chicken leukemia retroviruses, because of their capacity to readily transform hematopoietic cells in vitro, are ideal models to study the mechanisms governing the cell-type specificity of oncoproteins. Here we analyzed the transformation specificity of 2 acute chicken leukemia retroviruses, the Myb-Ets– encoding E26 virus and the ErbA/ErbB-encoding avian erythroblastosis virus (AEV). While cells transformed by E26 are multipotent (designated “MEP” cells), those transformed by AEV resemble erythroblasts. Using antibodies to separate subpopulations of precirculation yolk sac cells, both viruses were found to induce the proliferation of primitive erythroid progenitors within 2 days of infection. However, while AEV induced a block in differentiation of the cells, E26 induced a gradual shift in their phenotype and the acquisition of the potential for multilineage differentiation. These results suggest that the Myb-Ets oncoprotein of the E26 leukemia virus converts primitive erythroid cells into proliferating definitive-type multipotent hematopoietic progenitors.

scholarly journals Substitution of the Human β-Spectrin Promoter for the Human Aγ-Globin Promoter Prevents Silencing of a Linked Human β-Globin Gene in Transgenic Mice

1998 ◽  
Vol 18 (11) ◽  
pp. 6634-6640 ◽  
Author(s):  
Denise E. Sabatino ◽  
Amanda P. Cline ◽  
Patrick G. Gallagher ◽  
Lisa J. Garrett ◽  
George Stamatoyannopoulos ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Fetal Liver ◽  
Globin Gene ◽  
Gene Promoter ◽  
Yolk Sac ◽  
Globin Genes ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Globin Promoter ◽  
In Erythroid Cells

ABSTRACT During development, changes occur in both the sites of erythropoiesis and the globin genes expressed at each developmental stage. Previous work has shown that high-level expression of human β-like globin genes in transgenic mice requires the presence of the locus control region (LCR). Models of hemoglobin switching propose that the LCR and/or stage-specific elements interact with globin gene sequences to activate specific genes in erythroid cells. To test these models, we generated transgenic mice which contain the human Aγ-globin gene linked to a 576-bp fragment containing the human β-spectrin promoter. In these mice, the β-spectrin Aγ-globin (βsp/Aγ) transgene was expressed at high levels in erythroid cells throughout development. Transgenic mice containing a 40-kb cosmid construct with the micro-LCR, βsp/Aγ-, ψβ-, δ-, and β-globin genes showed no developmental switching and expressed both human γ- and β-globin mRNAs in erythroid cells throughout development. Mice containing control cosmids with the Aγ-globin gene promoter showed developmental switching and expressed Aγ-globin mRNA in yolk sac and fetal liver erythroid cells and β-globin mRNA in fetal liver and adult erythroid cells. Our results suggest that replacement of the γ-globin promoter with the β-spectrin promoter allows the expression of the β-globin gene. We conclude that the γ-globin promoter is necessary and sufficient to suppress the expression of the β-globin gene in yolk sac erythroid cells.

Primitive and Definitive Erythropoiesis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. SCI-37-SCI-37
Author(s):  
James Palis
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Yolk Sac ◽  
Erythroid Cells ◽  
Transient Wave ◽  
Self Renewal ◽  
Primitive Erythropoiesis ◽  
Definitive Erythropoiesis

Abstract Abstract SCI-37 Studies in mammalian and nonmammalian vertebrate embryos indicate that erythropoiesis comes in two flavors: primitive and definitive. The primitive erythroid lineage in mammalian embryos is characterized by a transient wave of lineage-committed progenitors that emerge from the yolk sac and generate a wave of precursors that synchronously mature in the bloodstream. Primitive erythroid precursors dynamically regulate embryonic globin gene expression and ultimately enucleate to form erythrocytes. Primitive erythropoiesis is superseded by definitive erythroid cells that mature extravascularly in association with macrophage cells. Studies in the mouse embryo indicate that definitive erythropoiesis has two distinct developmental origins. The first is a transient wave of erythro-myeloid progenitors (EMP) that emerge from the yolk sac and seed the early fetal liver. The second is a long-term program of erythropoiesis derived from hematopoietic stem cells. Erythropoietin is the central regulator of definitive erythropoiesis, in part by regulating the survival of committed progenitors. In contrast, the role of erythropoietin in primitive erythropoiesis remains poorly understood. Recent studies indicate that erythropoietin does not regulate the primitive erythroid progenitor compartment, but rather plays a critical role in establishing an antiapoptotic state during the terminal maturation of primitive erythroblasts. EMP-derived proerythroblasts are capable of extensive self-renewal in vitro, while primitive erythroid progenitors are incapable of self-renewal under the same conditions. These studies, taken together, indicate that the primitive and definitive forms of erythropoiesis have fundamental differences in the regulation of red cell output. The overlapping emergence of primitive and definitive erythroid lineages in differentiating embryonic stem cells suggests that the transient yolk-sac-derived primitive and EMP-derived definitive erythroid programs are recapitulated in vitro. These studies offer the hope that human embryonic stem cells can serve as a source of functional definitive erythroid cells for transfusion therapy. Disclosures: No relevant conflicts of interest to declare.

Inhibition of erythropoiesis in malaria anemia: role of hemozoin and hemozoin-generated 4-hydroxynonenal

Blood ◽  
2010 ◽  
Vol 116 (20) ◽  
pp. 4328-4337 ◽  
Author(s):  
Oleksii A. Skorokhod ◽  
Luisa Caione ◽  
Tiziana Marrocco ◽  
Giorgia Migliardi ◽  
Valentina Barrera ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Unsaturated Fatty Acids ◽  
Major Effect ◽  
Receptor Expression ◽  
Erythroid Cells ◽  
Erythroid Progenitors ◽  
Inhibitory Molecule ◽  
Cycle Regulation

Abstract Severe malaria anemia is characterized by inhibited/altered erythropoiesis and presence of hemozoin-(HZ)-laden bone-marrow macrophages. HZ mediates peroxidation of unsaturated fatty acids and production of bioactive aldehydes such as 4-hydroxynonenal (HNE). HZ-laden human monocytes inhibited growth of cocultivated human erythroid cells and produced HNE that diffused to adjacent cells generating HNE-protein adducts. Cocultivation with HZ or treatment with low micromolar HNE inhibited growth of erythroid cells interfering with cell cycle without apoptosis. After HZ/HNE treatment, 2 critical proteins in cell-cycle regulation, p53 and p21, were increased and the retinoblastoma protein, central regulator of G1-to-S-phase transition, was con-sequently hypophosphorylated, while GATA-1, master transcription factor in erythropoiesis was reduced. The resultant decreased expression of cyclin A and D2 retarded cell-cycle progression in erythroid cells and the K562 cell line. As a second major effect, HZ and HNE inhibited protein expression of crucial receptors (R): transferrinR1, stem cell factorR, interleukin-3R, and erythropoietinR. The reduced receptor expression and the impaired cell-cycle activity decreased the production of cells expressing glycophorin-A and hemoglobin. Present data confirm the inhibitory role of HZ, identify HNE as one HZ-generated inhibitory molecule and describe molecular targets of HNE in erythroid progenitors possibly involved in erythropoiesis inhibition in malaria anemia.

scholarly journals GATA-4 Incompletely Substitutes for GATA-1 in Promoting Both Primitive and Definitive Erythropoiesis in Vivo

2006 ◽  
Vol 281 (43) ◽  
pp. 32820-32830 ◽  
Author(s):  
Sakie Hosoya-Ohmura ◽  
Naomi Mochizuki ◽  
Mikiko Suzuki ◽  
Osamu Ohneda ◽  
Kinuko Ohneda ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Germ Line ◽  
Fetal Liver ◽  
Chimeric Protein ◽  
Terminal Region ◽  
Erythroid Cell ◽  
Erythroid Cells ◽  
Gata Factors ◽  
Primitive Erythropoiesis

Vertebrate GATA transcription factors have been classified into two subgroups; GATA-1, GATA-2, and GATA-3 are expressed in hematopoietic cells, whereas GATA-4, GATA-5, and GATA-6 are expressed in mesoendoderm-derived tissues. We previously discovered that expression of GATA-2 or GATA-3 under the transcriptional control for the Gata1 gene eliminates lethal anemia in Gata1 germ line mutant mice (Gata1.05/Y). Here, we show that the GATA-4 expression by the same regulatory cassette prolongs the life span of Gata1.05/Y embryos from embryonic day 12.5 to 15.5 but fails to abrogate its embryonic lethality. Gata1.05/Y mice bearing the GATA-4 transgene showed impaired maturation of both primitive and definitive erythroid cells and defective erythroid cell expansion in fetal liver. Moreover, the incidence of apoptosis was observed prominently in primitive erythroid cells. In contrast, a GATA-4-GATA-1 chimeric protein prepared by linking the N-terminal region of GATA-4 to the C-terminal region of GATA-1 significantly promoted the differentiation and survival of primitive erythroid cells, although this protein is still insufficient for rescuing Gata1.05/Y embryos from lethal anemia. These data thus show a functional incompatibility between hematopoietic and endodermal GATA factors in vivo and provide evidence indicating specific roles of the C-terminal region of GATA-1 in primitive erythropoiesis.

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