Role for BH3-Only Protein NOXA In Growth-Factor Deprivation and Early Erythropoiesis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4235-4235
Author(s):  
Christian R. Geest ◽  
Felix M. Wensveen ◽  
Sten F.W.M. Libregts ◽  
Alex M. de Bruin ◽  
Ingrid A.M. Derks ◽  
...  
Keyword(s):  
Growth Factor ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Erythroid Progenitor ◽  
Apoptosis Pathway ◽  
Cell Production ◽  
Growth Factor Deprivation ◽  
Redundant Role

Abstract Abstract 4235 Red blood cell production is a strictly regulated process and homeostatic maintenance of the erythropoietic system requires equilibrium between the rate of erythroid cell production and red blood cell destruction. Hematopoietic cytokines play a crucial role in regulating expansion, differentiation and survival of erythrocyte progenitors. Shortage of growth factors triggers the mitochondrial apoptosis pathway, which is critically dependent on Bcl-2 family members. However, the contribution of this mechanism in the regulation of erythropoiesis remains ill-defined. This prompted us to screen for candidate genes involved in this process in erythroid progenitors. We found that the expression of Noxa, a pro-apoptotic Bcl-2 family member, is upregulated during erythroid differentiation and following cytokine-withdrawal in erythroid progenitor cells. Knockdown or deletion of Noxa in IL-3 dependent human and murine erythroid progenitor cell lines increased Mcl-1 levels, which correlated with markedly decreased apoptosis following cytokine withdrawal. Importantly, Noxa ablation in mice increased extra-medullary erythropoiesis, resulting in enhanced numbers of early splenic erythroblasts and circulating reticulocytes. Noxa-deficient hematopoietic progenitors were more resistant to apoptosis induced by growth factor deprivation and displayed increased colony-forming potential. In addition, combined loss of Noxa and Bim resulted in enhanced resistance of erythroid progenitors to cytokine withdrawal compared to WT or single Bim knockouts, suggesting a non-redundant role for Noxa and Bim in regulating survival of erythroid progenitors in response to cytokine deprivation. Finally, in a model of acute haemolytic anaemia, deletion of Noxa enhanced subsequent hematocrit recovery. Together, these findings identify a non-redundant role for BH3-only protein Noxa in the regulation of erythroblast survival during early erythropoiesis. Therefore, Noxa may be a novel component to control red blood cell numbers and modulation of this pathway could be envisaged in therapeutic options for treatment of anaemia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Erythropoietin in Brain Development and Beyond

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Mawadda Alnaeeli ◽  
Li Wang ◽  
Barbora Piknova ◽  
Heather Rogers ◽  
Xiaoxia Li ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Types ◽  
Erythropoietin Receptor ◽  
Adult Brain ◽  
Receptor Expression ◽  
Neural Cells ◽  
Erythroid Progenitor ◽  
Cell Production ◽  
Oxygen Carrying Capacity

Erythropoietin is known as the requisite cytokine for red blood cell production. Its receptor, expressed at a high level on erythroid progenitor/precursor cells, is also found on endothelial, neural, and other cell types. Erythropoietin and erythropoietin receptor expression in the developing and adult brain suggest their possible involvement in neurodevelopment and neuroprotection. During ischemic stress, erythropoietin, which is hypoxia inducible, can contribute to brain homeostasis by increasing red blood cell production to increase the blood oxygen carrying capacity, stimulate nitric oxide production to modulate blood flow and contribute to the neurovascular response, or act directly on neural cells to provide neuroprotection as demonstrated in culture and animal models. Clinical studies of erythropoietin treatment in stroke and other diseases provide insight on safety and potential adverse effects and underscore the potential pleiotropic activity of erythropoietin. Herein, we summarize the roles of EPO and its receptor in the developing and adult brain during health and disease, providing first a brief overview of the well-established EPO biology and signaling, its hypoxic regulation, and role in erythropoiesis.

Regulatory Role Of Mitochondrial Aconitase and Isocitrate In Iron-Responsive, Erythropoietin Receptor Signaling During Anemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3443-3443
Author(s):  
Grant C Bullock ◽  
Valerie Schrott
Keyword(s):  
Iron Deficiency ◽  
Blood Cell ◽  
Chronic Inflammation ◽  
Red Blood Cell ◽  
Refractory Anemia ◽  
Deficiency Anemia ◽  
Erythroid Progenitors ◽  
Cell Production ◽  
Clinical Observations ◽  
Mitochondrial Aconitase

Abstract Several clinical observations illustrate the link between iron and erythropoietin (Epo)-mediated signaling in early erythroid progenitor cells. In iron deficiency anemia (IDA) erythropoiesis is blocked at an early stage despite increased serum Epo concentrations. Intravenous iron improves the effectiveness of exogenous Epo in patients with Epo-refractory anemia of chronic disease. These clinical observations suggest that iron dominantly regulates Epo-receptor (EpoR) signaling. However, the mechanism of this iron-mediated signaling remains unclear. We recently demonstrated that 1) the aconitases, multifunctional iron-sulfur cluster proteins that convert citrate into isocitrate are essential in the iron- Epo-signaling pathway in early erythroid progenitors, and that 2) isocitrate, the downstream product of aconitase, can enhance the effectiveness of Epo during iron deficiency in vitro and in vivo in mice with IDA and in rats with the anemia of chronic inflammation. These observations suggest that isocitrate or derivatives of isocitrate that synergize with erythropoiesis stimulating agents have important therapeutic application in the treatment of anemia. New data from my lab also shows that cellular iron restriction regulates mitochondrial oxygen consumption rates differentially over time during red blood cell differentiation, suggesting a novel link between mitochondrial function and erythropoeisis. We also see an increase in mitochondrial superoxide anion production in iron deprived erythroid progenitors. Based on these data, we hypothesize that mitochondrial aconitase is an iron sensor that integrates mitochondrial redox signaling to EpoR signaling and subsequent red blood cell production. To test this hypothesis we are investigating the iron dependent mechanisms by which aconitase, isocitrate, reactive oxygen species and mitochondrial metabolic pathways alter EpoR signaling. The clinical relevance of this project lies in its potential for the development of new iron-free agonists and antagonists of red blood cell production. Agonists may benefit patients with anemia due to iron deficiency or chronic inflammation and antagonists may benefit patients with myeloproliferative neoplasms. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Complete Spatial Mapping of Steady-State Erythropoiesis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 274-274
Author(s):  
Qingqing Wu ◽  
Jizhou Zhang ◽  
Courtney Johnson ◽  
Anastasiya Slaughter ◽  
Margot Lindsay May ◽  
...  
Keyword(s):  
Cell Surface ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Differentially Expressed ◽  
Cell Maturation ◽  
Erythroid Cells ◽  
Erythroid Progenitors ◽  
Erythroid Progenitor ◽  
Mature Erythrocyte

Lack of markers to image the different progenitors has limited analyses of interactions between HSPC and their offspring. To overcome this we analyzed the expression of 250+ cell surface molecules for which antibodies are commonly available in all hematopoietic progenitors. We found 76 differentially expressed markers in at least one HSPC showing medium to bright fluorescence suggesting that many commonly used cell surface markers can be used to prospectively image HSPC in the bone marrow. We focused in erythropoiesis as it has not been possible to image step-wise red blood cell maturation in vivo. We found that all erythroid progenitors can be defined as Ly6C-CD27-ESAM-CD117+ cells and then Pre-MegE (earliest erythroid progenitor Cell Stem Cell. 2007 1(4):428-42) are CD150+CD71-. These give rise to CD71+CD150+ Pre-CFU-E that differentiate into CD71+CD150- CFU-E that then generate early erythroblasts. All BM BFU-E activity was restricted to Pre-MegE and CFU-E (70 and 30% of all BFU-E) whereas all CFU-E colonies were spread between Pre-MegE (44%), pre-CFU-E (10%) and CFU-E (46%). We also confirmed previously published data showing that CD71 and Ter119 can be used to image step-wise terminal erythropoiesis; CD71+Ter119dim early erythroblasts, CD71+Ter119bright late erythroblasts, CD71dimTer119bright reticulocytes and CD71-Ter119bright erythrocytes. Importantly, all populations were detected at identical frequencies using FACS or confocal imaging indicating that our imaging strategy detects all erythroid cells in the BM (Pre-CFU-E: 0.022 vs 0.027 %; CFUE: 0.32 vs 0.30%; Early-Ery: 0.62 vs 0.66%; Late-Ery: 32.05 vs 32.12%; Reticulocyte: 5.98 vs. 3.36%; Erythrocytes: 12.49 vs. 13.47%). We mapped the 3D location of every erythroid lineage cell in the murine sternal BM and interrogate the spatial relationships between the different maturation steps and with candidate niches. We compared the interactions found in vivo with those found in random simulations. Specifically, we used CD45 and Ter119 to obtain the spatial coordinates of every hematopoietic cell in a mouse sternum. Then we randomly placed each type of erythroid lineage cell at identical frequencies as those found in vivo to generate random simulation. We found that Pre-MegE and Pre-CFU-E are closer to each other than predicted from random (average Pre-CFU-E to Pre-MegE distance= 92.3 µm vs. 156.7 µm random, p=0.028) but never adjacent indicating that Pre-CFU-E migrate away from Pre-MegE (0% of Pre-CFU-E adjacent to PreMegE). We also found that CFU-E were not adjacent to pre CFU-E, instead 7-8 CFU-E align to form "CFU-E strings" along the central BM (74% of CFU-E found in strings vs. 17.5% in random p<0.0001). Early erythroblasts form elongated clusters (66% early erythroblasts found within 10µm of another vs 10% in random p<0.0001) that emerge from these CFU-E strings like buds on a tree branch. Each of these early erythroblasts buds is enveloped by a large cluster of late erythroblasts, a reticulocyte cluster, and a mature erythrocyte cluster (68% of early erythroblasts buds form this 4-cluster structure vs.0% of random, P<0.0001). A recent study suggested that BM endothelial cells regulate erythroid progenitors via SCF. We found that the CFU-E strings sit on top of central BM sinusoids (average CFU-E to sinusoid distance= 0.8µm observed vs. 8.562μm random; P<0.0001) but are selectively depleted from arterioles (average CFU-E to arterioles distance=176 µm observed vs. 90.98 µm random, P<0.0001). In contrast downstream erythroid cells are farther away from sinusoids (average Early-Erythroblast to sinusoid distance=5.995 µm vs.8.224 µm random, P<0.0001; Late-erythroblast: 6.552 µm vs.9.053 µm random, P<0.0001; Reticulocytes: 6.013 µm vs.9.844 µm random, P<0.0001; Erythrocytes: 6.520 µm vs.8.986 µm random, P<0.0001). These suggest a model in which CFU-E progenitors are selectively recruited to sinusoids where they self-renew to generate strings of progenitors from which immature erythroblasts arise and mature while migrating away from the sinusoid. In summary we have found 76 differentially expressed markers that can be combined to detect most HSPC; validated a 5-color stain to image all steps of red blood cell maturation; demonstrated that erythropoiesis takes place in highly organized 4-cluster structures emerging from strings of sinusoidal CFU-E, and demonstrated that sinusoids are the exclusive site of erythropoiesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals TGF-β inhibitors stimulate red blood cell production by enhancing self-renewal of BFU-E erythroid progenitors

Blood ◽  
2016 ◽  
Vol 128 (23) ◽  
pp. 2637-2641 ◽  
Author(s):  
Xiaofei Gao ◽  
Hsiang-Ying Lee ◽  
Edroaldo Lummertz da Rocha ◽  
Cheng Zhang ◽  
Yi-Fen Lu ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Erythroid Progenitors ◽  
Self Renewal ◽  
Cell Production ◽  
Type Iii ◽  
Key Points ◽  
Β Receptor

Key Points The type III TGF-β receptor is a marker that distinguishes “early” and “late” BFU-Es. TGF-β inhibitors increase early BFU-E cell self-renewal and total erythroblast production.

Scanning Electron Microscopy Reveals Two Distinct Classes of Erythroblastic Island Isolated from Adult Mammalian Bone Marrow

2016 ◽  
Vol 22 (2) ◽  
pp. 368-378 ◽  
Author(s):  
Jia Hao Yeo ◽  
Bronwyn M. McAllan ◽  
Stuart T. Fraser
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Surface Proteins ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Hematological Disorders ◽  
And Function ◽  
Scanning Electron

AbstractErythroblastic islands are multicellular clusters in which a central macrophage supports the development and maturation of red blood cell (erythroid) progenitors. These clusters play crucial roles in the pathogenesis observed in animal models of hematological disorders. The precise structure and function of erythroblastic islands is poorly understood. Here, we have combined scanning electron microscopy and immuno-gold labeling of surface proteins to develop a better understanding of the ultrastructure of these multicellular clusters. The erythroid-specific surface antigen Ter-119 and the transferrin receptor CD71 exhibited distinct patterns of protein sorting during erythroid cell maturation as detected by immuno-gold labeling. During electron microscopy analysis we observed two distinct classes of erythroblastic islands. The islands varied in size and morphology, and the number and type of erythroid cells interacting with the central macrophage. Assessment of femoral marrow isolated from a cavid rodent species (guinea pig,Cavis porcellus) and a marsupial carnivore species (fat-tailed dunnarts,Sminthopsis crassicaudata) showed that while the morphology of the central macrophage varied, two different types of erythroblastic islands were consistently identifiable. Our findings suggest that these two classes of erythroblastic islands are conserved in mammalian evolution and may play distinct roles in red blood cell production.

scholarly journals Fetal calf serum contains activities that induce fetal hemoglobin in adult erythroid cell cultures

Blood ◽  
1990 ◽  
Vol 75 (9) ◽  
pp. 1862-1869 ◽  
Author(s):  
P Constantoulakis ◽  
B Nakamoto ◽  
T Papayannopoulou ◽  
G Stamatoyannopoulos
Keyword(s):  
Cell Cultures ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Fetal Hemoglobin ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Globin Mrna ◽  
Erythroid Progenitor ◽  
Fetal Sheep ◽  
Gamma Globin

Abstract Cultures of peripheral blood or bone marrow erythroid progenitors display stimulated production of fetal hemoglobin. We investigated whether this stimulation is due to factors contained in the sera of the culture medium. Comparisons of gamma/gamma + beta biosynthetic ratios in erythroid colonies grown in fetal calf serum (FCS) or in charcoal treated FCS (C-FCS) showed that FCS-grown cells had significantly higher gamma/gamma + beta ratios. This increase in globin chain biosynthesis was reflected by an increase in relative amounts of steady- state gamma-globin mRNA. In contrast to its effect on adult cells, FCS failed to influence gamma-chain synthesis in fetal burst forming units- erythroid (BFU-E) colonies. There was a high correlation of gamma- globin expression in paired cultures done with C-FCS or fetal sheep serum. Dose-response experiments showed that the induction of gamma- globin expression is dependent on the concentration of FCS. These results indicate that FCS contains an activity that induces gamma- globin expression in adult erythroid progenitor cell cultures.

Growth and Differentiation of Human Stem Cell Factor/Erythropoietin-Dependent Erythroid Progenitor Cells In Vitro

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke
Keyword(s):  
Stem Cell ◽  
Progenitor Cells ◽  
Stem Cell Factor ◽  
Large Cell ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Peripheral Blood Stem Cells ◽  
Erythroid Progenitor ◽  
Cell Numbers

Abstract Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.

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