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Tátrai P, Gergely F. Centrosome function is critical during terminal erythroid differentiation. EMBO J 2022; 41:e108739. [PMID: 35678476 PMCID: PMC9289712 DOI: 10.15252/embj.2021108739] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 05/03/2022] [Accepted: 05/25/2022] [Indexed: 11/26/2022] Open
Abstract
Red blood cells are produced by terminal erythroid differentiation, which involves the dramatic morphological transformation of erythroblasts into enucleated reticulocytes. Microtubules are important for enucleation, but it is not known if the centrosome, a key microtubule-organizing center, is required as well. Mice lacking the conserved centrosome component, CDK5RAP2, are likely to have defective erythroid differentiation because they develop macrocytic anemia. Here, we show that fetal liver-derived, CDK5RAP2-deficient erythroid progenitors generate fewer and larger reticulocytes, hence recapitulating features of macrocytic anemia. In erythroblasts, but not in embryonic fibroblasts, loss of CDK5RAP2 or pharmacological depletion of centrosomes leads to highly aberrant spindle morphologies. Consistent with such cells exiting mitosis without chromosome segregation, tetraploidy is frequent in late-stage erythroblasts, thereby giving rise to fewer but larger reticulocytes than normal. Our results define a critical role for CDK5RAP2 and centrosomes in spindle formation specifically during blood production. We propose that disruption of centrosome and spindle function could contribute to the emergence of macrocytic anemias, for instance, due to nutritional deficiency or exposure to chemotherapy.
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Affiliation(s)
- Péter Tátrai
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
- Present address:
Solvo BiotechnologyBudapestHungary
| | - Fanni Gergely
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
- Department of BiochemistryUniversity of OxfordOxfordUK
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2
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Soboleva S, Miharada K. Induction of enucleation in primary and immortalized erythroid cells. Int J Hematol 2022; 116:192-198. [PMID: 35610497 DOI: 10.1007/s12185-022-03386-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 10/18/2022]
Abstract
Enucleation is a crucial event during the erythropoiesis, implicating drastic morphologic and transcriptomic/proteomic changes. While many genes deletion lead to failed or impaired enucleation have been identified, directly triggering the erythroid maturation, particularly enucleation, is still challenging. Inducing enucleation at the desired timing is necessary to develop efficient methods to generate mature, fully functional red blood cells in vitro for future transfusion therapies. However, there are considerable differences between primary erythroid cells and cultured cell sources, particularly pluripotent stem cell-derived erythroid cells and immortalized erythroid cell lines. For instance, the difference in the proliferative status between those cell types could be a critical factor, as cell cycle exit is closely connected to the terminal maturation of primary. In this review, we will discuss previous findings on the enucleation machinery and current challengings to trigger the enucleation of infinite erythroid cell sources.
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Affiliation(s)
- Svetlana Soboleva
- Division of Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Kenichi Miharada
- Division of Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden. .,International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan.
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3
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Stevens-Hernandez CJ, Bruce LJ. Reticulocyte Maturation. MEMBRANES 2022; 12:membranes12030311. [PMID: 35323786 PMCID: PMC8953437 DOI: 10.3390/membranes12030311] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 02/04/2023]
Abstract
Changes to the membrane proteins and rearrangement of the cytoskeleton must occur for a reticulocyte to mature into a red blood cell (RBC). Different mechanisms of reticulocyte maturation have been proposed to reduce the size and volume of the reticulocyte plasma membrane and to eliminate residual organelles. Lysosomal protein degradation, exosome release, autophagy and the extrusion of large autophagic–endocytic hybrid vesicles have been shown to contribute to reticulocyte maturation. These processes may occur simultaneously or perhaps sequentially. Reticulocyte maturation is incompletely understood and requires further investigation. RBCs with membrane defects or cation leak disorders caused by genetic variants offer an insight into reticulocyte maturation as they present characteristics of incomplete maturation. In this review, we compare the structure of the mature RBC membrane with that of the reticulocyte. We discuss the mechanisms of reticulocyte maturation with a focus on incomplete reticulocyte maturation in red cell variants.
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Affiliation(s)
- Christian J. Stevens-Hernandez
- Bristol Institute for Transfusion Sciences, National Health Service (NHS) Blood and Transplant, Bristol BS34 7QH, UK;
- School of Biochemistry, University of Bristol, Bristol BS8 ITD, UK
| | - Lesley J. Bruce
- Bristol Institute for Transfusion Sciences, National Health Service (NHS) Blood and Transplant, Bristol BS34 7QH, UK;
- Correspondence:
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4
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A new role of glutathione peroxidase 4 during human erythroblast enucleation. Blood Adv 2021; 4:5666-5680. [PMID: 33211827 DOI: 10.1182/bloodadvances.2020003100] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
The selenoprotein glutathione peroxidase 4 (GPX4), the only member of the glutathione peroxidase family able to directly reduce cell membrane-oxidized fatty acids and cholesterol, was recently identified as the central regulator of ferroptosis. GPX4 knockdown in mouse hematopoietic cells leads to hemolytic anemia and to increased spleen erythroid progenitor death. The role of GPX4 during human erythropoiesis is unknown. Using in vitro erythroid differentiation, we show here that GPX4-irreversible inhibition by 1S,3R-RSL3 (RSL3) and its short hairpin RNA-mediated knockdown strongly impaired enucleation in a ferroptosis-independent manner not restored by tocopherol or iron chelators. During enucleation, GPX4 localized with lipid rafts at the cleavage furrows between reticulocytes and pyrenocytes. Its inhibition impacted enucleation after nuclear condensation and polarization and was associated with a defect in lipid raft clustering (cholera toxin staining) and myosin-regulatory light-chain phosphorylation. Because selenoprotein translation and cholesterol synthesis share a common precursor, we investigated whether the enucleation defect could represent a compensatory mechanism favoring GPX4 synthesis at the expense of cholesterol, known to be abundant in lipid rafts. Lipidomics and filipin staining failed to show any quantitative difference in cholesterol content after RSL3 exposure. However, addition of cholesterol increased cholera toxin staining and myosin-regulatory light-chain phosphorylation, and improved enucleation despite GPX4 knockdown. In summary, we identified GPX4 as a new actor of human erythroid enucleation, independent of its function in ferroptosis control. We described its involvement in lipid raft organization required for contractile ring assembly and cytokinesis, leading in fine to nucleus extrusion.
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Menon V, Ghaffari S. Erythroid enucleation: a gateway into a "bloody" world. Exp Hematol 2021; 95:13-22. [PMID: 33440185 PMCID: PMC8147720 DOI: 10.1016/j.exphem.2021.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 12/18/2022]
Abstract
Erythropoiesis is an intricate process starting in hematopoietic stem cells and leading to the daily production of 200 billion red blood cells (RBCs). Enucleation is a greatly complex and rate-limiting step during terminal maturation of mammalian RBC production involving expulsion of the nucleus from the orthochromatic erythroblasts, resulting in the formation of reticulocytes. The dynamic enucleation process involves many factors ranging from cytoskeletal proteins to transcription factors to microRNAs. Lack of optimum terminal erythroid maturation and enucleation has been an impediment to optimum RBC production ex vivo. Major efforts in the past two decades have exposed some of the mechanisms that govern the enucleation process. This review focuses in detail on mechanisms implicated in enucleation and discusses the future perspectives of this fascinating process.
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Affiliation(s)
- Vijay Menon
- Department of Cell, Developmental & Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Saghi Ghaffari
- Department of Cell, Developmental & Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY; Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY.
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6
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Kaido M, Takagi Y, Kono M, Nakazawa F, Yamamoto S, Wada A, Morikawa T. Investigation of morphological changes for the discrimination of nucleated red blood cells and other leukocytes in Sysmex XN hematology analyzer scattergrams using transmission electron microscopy. Pract Lab Med 2017; 8:70-76. [PMID: 28856231 PMCID: PMC5575374 DOI: 10.1016/j.plabm.2017.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 04/21/2017] [Accepted: 05/01/2017] [Indexed: 11/25/2022] Open
Abstract
Background The WNR channel of the XN-Series automated hematology analyzer (Sysmex) counts white blood cells (WBCs) and simultaneously performs a differential counting of basophils and nucleated red blood cells (NRBCs). The detection process involves exposing the cells to WNR-specific reagents containing an acidic detergent and a fluorescent dye and measuring the intensity of the forward scattered light (FSC) and side fluorescence light (SFL). Method We treated isolated peripheral WBCs and NRBCs with specific reagents and assessed the morphological changes in NRBCs and each leukocyte type using transmission electron microscopy (TEM). Results The results from a flow cytometer (FCM) showed that, after exposure to the reagents, basophils appeared on the highest FSC and SFL areas compared to other leukocytes on the WNR scattergram. Owing to the hemolysis of reticulocytes and erythrocytes, NRBCs that survived the reagent treatment could be distinguished by their lower intensity than those of the other leukocytes on the WNR scattergram. We investigated the significance of the relationship between the TEM and FCM results after the reagent treatment. Conclusion We confirmed that the WNR channel differentiates the blood cells on the WNR scattergram based on differences in the amount of residual cytoplasm and nucleic acids. The WNR channel of the XN-Series counts WBCs and simultaneously performs a differential count of basophils and NRBCs. Basophils had the highest scattered light and fluorescent intensities after WNR treatment on a flow cytometer scattergram. NRBCs survived treatment with the WNR reagents had a lower intensity on the FCM scattergram than those of other leukocytes. TEM revealed that the WNR channel can differentiate blood cells based on the amount of residual cytoplasm and nucleic acids.
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Key Words
- Automated hematology analyzer
- EDTA, ethylenediaminetetraacetic acid
- FCM, flow cytometer
- FITC, fluorescein isothiocyanate
- FSC, forward scattered light
- Flow cytometry
- Fluorescent intensity
- Leukocytes
- MACS, magnetic cell sorting
- MAS, Matsunami Adhesive Silane
- NRBCs
- NRBCs, nucleated red blood cells
- PE, phycoerythrin
- SFL, side fluorescence light
- Scatter light intensity
- TEM, transmission electron microscopy
- Transmission electron microscopy
- WBCs, white blood cells
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Affiliation(s)
- Masako Kaido
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Yuri Takagi
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Mari Kono
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Fumie Nakazawa
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Shiori Yamamoto
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Atsushi Wada
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
| | - Takashi Morikawa
- Scientific Research, Scientific Affairs, Sysmex Corporation, 1-3-2 Murotani, Nishi-ku, Kobe 651-2241, Japan
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7
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Mazurier C, Douay L. [In vitro generation of blood red cells from stem cells: a sketch of the future]. Biol Aujourdhui 2016; 210:9-17. [PMID: 27286576 DOI: 10.1051/jbio/2016008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 11/15/2022]
Abstract
Human adult pluripotent stem cells, stem cells of embryonic origin and induced pluripotent stem cells (iPS) provide cellular sources for new promising regenerative medicine approaches. Because these cells can be patient-specific, they allow considering a personalized medicine appropriate to the diagnosis of each. The generation of cultured red blood cells (cRBC) derived from stem cells is emblematic of personalized medicine. Indeed, these cells have the advantage of being selected according to a blood phenotype of interest and they may provide treatments to patients in situation of impossible transfusion (alloimmunized patients, rare phenotypes). Essential progresses have established proof of concept for this approach, still a concept some years ago. From adult stem cells, all steps of upstream research were successfully achieved, including the demonstration of the feasibility of injection into human. This leads us to believe that Red Blood Cells generated in vitro from stem cells will be the future players of blood transfusion. However, although theoretically ideal, these stem cells raise many biological challenges to overcome, although some tracks are identified.
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Affiliation(s)
- Christelle Mazurier
- INSERM, UMRS938, Prolifération et différenciation des cellules souches, 75012 Paris, France - Etablissement Français du Sang Ile de France, Unité d'ingénierie et de thérapie cellulaire, 94017 Créteil, France - UPMC Université ParisVI, UMRS938 CDR Saint-Antoine, Prolifération et différenciation des cellules souches, 75012 Paris, France
| | - Luc Douay
- INSERM, UMRS938, Prolifération et différenciation des cellules souches, 75012 Paris, France - Etablissement Français du Sang Ile de France, Unité d'ingénierie et de thérapie cellulaire, 94017 Créteil, France - UPMC Université ParisVI, UMRS938 CDR Saint-Antoine, Prolifération et différenciation des cellules souches, 75012 Paris, France - AP-HP, Hôpital Armand Trousseau et Saint-Antoine, Service d'Hématologie et Immunologie Biologiques, 75012 Paris, France
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8
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Simamura E, Arikawa T, Ikeda T, Shimada H, Shoji H, Masuta H, Nakajima Y, Otani H, Yonekura H, Hatta T. Melanocortins contribute to sequential differentiation and enucleation of human erythroblasts via melanocortin receptors 1, 2 and 5. PLoS One 2015; 10:e0123232. [PMID: 25860801 PMCID: PMC4393082 DOI: 10.1371/journal.pone.0123232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/17/2015] [Indexed: 11/30/2022] Open
Abstract
In this study, we showed that adrenocorticotropic hormone (ACTH) promoted erythroblast differentiation and increased the enucleation ratio of erythroblasts. Because ACTH was contained in hematopoietic medium as contamination, the ratio decreased by the addition of anti-ACTH antibody (Ab). Addition of neutralizing Abs (nAbs) for melanocortin receptors (MCRs) caused erythroblast accumulation at specific stages, i.e., the addition of anti-MC2R nAb led to erythroblast accumulation at the basophilic stage (baso-E), the addition of anti-MC1R nAb caused accumulation at the polychromatic stage (poly-E), and the addition of anti-MC5R nAb caused accumulation at the orthochromatic stage (ortho-E). During erythroblast differentiation, ERK, STAT5, and AKT were consecutively phosphorylated by erythropoietin (EPO). ERK, STAT5, and AKT phosphorylation was inhibited by blocking MC2R, MC1R, and MC5R, respectively. Finally, the phosphorylation of myosin light chain 2, which is essential for the formation of contractile actomyosin rings, was inhibited by anti-MC5R nAb. Taken together, our study suggests that MC2R and MC1R signals are consecutively required for the regulation of EPO signal transduction in erythroblast differentiation, and that MC5R signal transduction is required to induce enucleation. Thus, melanocortin induces proliferation and differentiation at baso-E, and polarization and formation of an actomyosin contractile ring at ortho-E are required for enucleation.
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MESH Headings
- Adrenocorticotropic Hormone/antagonists & inhibitors
- Adrenocorticotropic Hormone/metabolism
- Antibodies, Neutralizing
- Cell Differentiation/physiology
- Cells, Cultured
- Erythroblasts/cytology
- Erythroblasts/metabolism
- Erythropoiesis/physiology
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Humans
- Melanocortins/metabolism
- Models, Biological
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Melanocortin, Type 1/antagonists & inhibitors
- Receptor, Melanocortin, Type 1/genetics
- Receptor, Melanocortin, Type 1/metabolism
- Receptor, Melanocortin, Type 2/antagonists & inhibitors
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/genetics
- Receptors, Melanocortin/metabolism
- STAT5 Transcription Factor/metabolism
- Signal Transduction
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Affiliation(s)
- Eriko Simamura
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Tomohiro Arikawa
- Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Takayuki Ikeda
- Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Shimada
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Shoji
- Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroko Masuta
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Yuriko Nakajima
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Otani
- Department of Developmental Biology, Faculty of Medicine, Shimane University, Izumo 693–8601, Japan
| | - Hideto Yonekura
- Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Toshihisa Hatta
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
- * E-mail:
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9
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Deezagi A, Abedi-Tashi M. Studying the enucleation process, DNA breakdown and telomerase activity of the K562 cell lines during erythroid differentiation in vitro. In Vitro Cell Dev Biol Anim 2013; 49:122-33. [PMID: 23288413 DOI: 10.1007/s11626-012-9574-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/26/2012] [Indexed: 11/30/2022]
Abstract
During erythropoiesis, some organelles such as mitochondria and nucleus are lost by autophagy and enucleation processes in the presence of macrophages in vivo. In vitro production of erythrocytes has raised many questions about the mechanism of enucleation. The aim of this work was to study the DNA breakdown, enucleation, hemoglobin synthesis and telomerase activity of K562 cells during erythroid differentiation. For these purposes, K562 cells were induced to differentiate by erythropoietin + rhGM-CSF, DMSO, and sodium butyrate separately up to 14 d. In different time intervals, hemoglobin synthesis was evaluated by benzidine staining and RT-PCR for γ-globin gene expression. DNA breakdown was analyzed by 4',6-diamidino-2-phenylindole (DAPI) staining, DNA ladder electrophoresis and comet assay. The telomerase activity was evaluated by TRAP assay. Our result indicated that, sodium butyrate and DMSO inhibited K562 cell growth about 50-60% in comparison to untreated control cells. The percentage of benzidine-positive cells was about 45% in the presence of sodium butyrate after 10 d. Densitometric analysis of RT-PCR and calculated data indicated a 1.5-fold increase in relative γ-globin gene expression at 96 h, in the presence of 1 mM sodium butyrate in comparison with untreated cells. DAPI staining did not reveal any evidence of internal lysis of the nucleus during erythroid differentiation at first wk, but this was obvious in the second wk. DNA laddering pattern was not observed in differentiated cells during 14 d. In comet assay, the percentage of DNA in tail, tail length, and tail moment were significantly different between untreated and treated cells (p < 0.05). Telomerase activity was inhibited up to 90.3% during erythroid differentiation of these cells.
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Affiliation(s)
- Abdolkhaleg Deezagi
- Department of Biochemistry, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
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10
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Ubukawa K, Sawada K. [Bone marrow failure syndrome (idiopathic hematopoietic disorders): progress in diagnosis and treatment. Topics: IV. Recent topics of hematopoiesis; 2. The mechanism of erythroblasts enucleation]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2012; 101:2002-9. [PMID: 22897005 DOI: 10.2169/naika.101.2002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kumi Ubukawa
- Department of Hematology, Nephrology and Rheumatology, Akita University Graduate School of Medicine, Japan
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11
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Abstract
To understand the role of cytoskeleton and membrane signaling molecules in erythroblast enucleation, we developed a novel analysis protocol of multiparameter high-speed cell imaging in flow. This protocol enabled us to observe F-actin and phosphorylated myosin regulatory light chain (pMRLC) assembled into a contractile actomyosin ring (CAR) between nascent reticulocyte and nucleus, in a population of enucleating erythroblasts. CAR formation and subsequent enucleation were not affected in murine erythroblasts with genetic deletion of Rac1 and Rac2 GTPases because of compensation by Rac3. Pharmacologic inhibition or genetic deletion of all Rac GTPases altered the distribution of F-actin and pMRLC and inhibited enucleation. Erythroblasts treated with NSC23766, cytochalasin-D, colchicine, ML7, or filipin that inhibited Rac activity, actin or tubulin polymerization, MRLC phosphorylation, or lipid raft assembly, respectively, exhibited decreased enucleation efficiency, as quantified by flow cytometry. As assessed by high-speed flow-imaging analysis, colchicine inhibited erythroblast polarization, implicating microtubules during the preparatory stage of enucleation, whereas NSC23766 led to absence of lipid raft assembly in the reticulocyte-pyrenocyte border. In conclusion, enucleation is a multistep process that resembles cytokinesis, requiring establishment of cell polarity through microtubule function, followed by formation of a contractile actomyosin ring, and coalescence of lipid rafts between reticulocyte and pyrenocyte.
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12
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Keerthivasan G, Wickrema A, Crispino JD. Erythroblast enucleation. Stem Cells Int 2011; 2011:139851. [PMID: 22007239 PMCID: PMC3189604 DOI: 10.4061/2011/139851] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 08/10/2011] [Indexed: 12/22/2022] Open
Abstract
Even though the production of orthochromatic erythroblasts can be scaled up to fulfill clinical requirements, enucleation remains one of the critical rate-limiting steps in the production of transfusable red blood cells. Mammalian erythrocytes extrude their nucleus prior to entering circulation, likely to impart flexibility and improve the ability to traverse through capillaries that are half the size of erythrocytes. Recently, there have been many advances in our understanding of the mechanisms underlying mammalian erythrocyte enucleation. This review summarizes these advances, discusses the possible future directions in the field, and evaluates the prospects for improved ex vivo production of red blood cells.
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Affiliation(s)
- Ganesan Keerthivasan
- Division of Hematology/Oncology, Northwestern University, Chicago, IL 60611, USA
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13
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Ji P, Murata-Hori M, Lodish HF. Formation of mammalian erythrocytes: chromatin condensation and enucleation. Trends Cell Biol 2011; 21:409-15. [PMID: 21592797 DOI: 10.1016/j.tcb.2011.04.003] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 04/13/2011] [Accepted: 04/13/2011] [Indexed: 01/14/2023]
Abstract
In all vertebrates, the cell nucleus becomes highly condensed and transcriptionally inactive during the final stages of red cell biogenesis. Enucleation, the process by which the nucleus is extruded by budding off from the erythroblast, is unique to mammals. Enucleation has critical physiological and evolutionary significance in that it allows an elevation of hemoglobin levels in the blood and also gives red cells their flexible biconcave shape. Recent experiments reveal that enucleation involves multiple molecular and cellular pathways that include histone deacetylation, actin polymerization, cytokinesis, cell-matrix interactions, specific microRNAs and vesicle trafficking; many evolutionarily conserved proteins and genes have been recruited to participate in this uniquely mammalian process. In this review, we discuss recent advances in mammalian erythroblast chromatin condensation and enucleation, and conclude with our perspectives on future studies.
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Affiliation(s)
- Peng Ji
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.
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14
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Abstract
Enucleation of mammalian erythroblasts is a process whose mechanism is largely undefined. The prevailing model suggests that nuclear extrusion occurs via asymmetric cytokinesis. To test this hypothesis, we treated primary erythroblasts with inhibitors of cytokinesis, including blebbistatin, hesperadin, and nocodazole, and then assayed for enucleation. Although these agents inhibited cell-cycle progression and subsequent enucleation when added early in culture, they failed to block enucleation proper when added to postmitotic cells. These results suggest that contraction of the actomyosin ring is not essential for nuclear expulsion. Next, by ultrastructural examination of primary erythroblasts, we observed an accumulation of vacuoles in the cytoplasm proximal to the extruding nucleus. This finding led us to hypothesize that vesicle trafficking contributes to erythroblast enucleation. Here, we show that chemical inhibitors of vesicle trafficking block enucleation of primary erythroblasts without affecting differentiation, cell division, or apoptosis. Moreover, knock-down of clathrin inhibited the enucleation of late erythroblasts. In contrast, vacuolin-1, a small molecule that induces vacuole formation, increased the percentage of enucleated cells. Together, these results illustrate that vesicle trafficking, specifically the formation, movement, and subsequent coalescence of vacuoles at the junction of the nucleus and the cytoplasm, is a critical component of mammalian erythroblast enucleation.
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15
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McGrath KE, Kingsley PD, Koniski AD, Porter RL, Bushnell TP, Palis J. Enucleation of primitive erythroid cells generates a transient population of "pyrenocytes" in the mammalian fetus. Blood 2008; 111:2409-17. [PMID: 18032705 PMCID: PMC2234067 DOI: 10.1182/blood-2007-08-107581] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 11/16/2007] [Indexed: 01/06/2023] Open
Abstract
Enucleation is the hallmark of erythropoiesis in mammals. Previously, we determined that yolk sac-derived primitive erythroblasts mature in the bloodstream and enucleate between embryonic day (E)14.5 and E16.5 of mouse gestation. While definitive erythroblasts enucleate by nuclear extrusion, generating reticulocytes and small, nucleated cells with a thin rim of cytoplasm ("pyrenocytes"), it is unclear by what mechanism primitive erythroblasts enucleate. Immunohistochemical examination of fetal blood revealed primitive pyrenocytes that were confirmed by multispectral imaging flow cytometry to constitute a distinct, transient cell population. The frequency of primitive erythroblasts was higher in the liver than the bloodstream, suggesting that they enucleate in the liver, a possibility supported by their proximity to liver macrophages and the isolation of erythroblast islands containing primitive erythroblasts. Furthermore, primitive erythroblasts can reconstitute erythroblast islands in vitro by attaching to fetal liver-derived macrophages, an association mediated in part by alpha4 integrin. Late-stage primitive erythroblasts fail to enucleate in vitro unless cocultured with macrophage cells. Our studies indicate that primitive erythroblasts enucleate by nuclear extrusion to generate erythrocytes and pyrenocytes and suggest this occurs in the fetal liver in association with macrophages. Continued studies comparing primitive and definitive erythropoiesis will lead to an improved understanding of terminal erythroid maturation.
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Affiliation(s)
- Kathleen E McGrath
- University of Rochester Medical Center, Department of Pediatrics, Center for Pediatric Biomedical Research, Rochester, NY 14642, USA
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16
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Abstract
Erythroblastic islands are specialized microenvironmental compartments within which definitive mammalian erythroblasts proliferate and differentiate. These islands consist of a central macrophage that extends cytoplasmic protrusions to a ring of surrounding erythroblasts. The interaction of cells within the erythroblastic island is essential for both early and late stages of erythroid maturation. It has been proposed that early in erythroid maturation the macrophages provide nutrients, proliferative and survival signals to the erythroblasts, and phagocytose extruded erythroblast nuclei at the conclusion of erythroid maturation. There is also accumulating evidence for the role of macrophages in promoting enucleation itself. The central macrophages are identified by their unique immunophenotypic signature. Their pronounced adhesive properties, ability for avid endocytosis, lack of respiratory bursts, and consequent release of toxic oxidative species, make them perfectly adapted to function as nurse cells. Both macrophages and erythroblasts display adhesive interactions that maintain island integrity, and elucidating these details is an area of intense interest and investigation. Such interactions enable regulatory feedback within islands via cross talk between cells and also trigger intracellular signaling pathways that regulate gene expression. An additional control mechanism for cellular growth within the erythroblastic islands is through the modulation of apoptosis via feedback loops between mature and immature erythroblasts and between macrophages and immature erythroblasts. The focus of this chapter is to outline the mechanisms by which erythroblastic islands aid erythropoiesis, review the historical data surrounding their discovery, and highlight important unanswered questions.
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Affiliation(s)
- Deepa Manwani
- Schneider Children's Hospital, New York, NY 11040, USA
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Soni S, Bala S, Gwynn B, Sahr KE, Peters LL, Hanspal M. Absence of erythroblast macrophage protein (Emp) leads to failure of erythroblast nuclear extrusion. J Biol Chem 2006; 281:20181-9. [PMID: 16707498 DOI: 10.1074/jbc.m603226200] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammals, the functional unit for definitive erythropoiesis is the erythroblastic island, a multicellular structure composed of a central macrophage surrounded by developing erythroblasts. Erythroblast-macrophage interactions play a central role in the terminal maturation of erythroblasts, including enucleation. One possible mediator of this cell-cell interaction is the protein Emp (erythroblast macrophage protein). We used targeted gene inactivation to define the function of Emp during hematopoiesis. Emp null embryos die perinatally and show profound alterations in the hematopoietic system. A dramatic increase in the number of nucleated, immature erythrocytes is seen in the peripheral blood of Emp null fetuses. In the fetal liver virtually no erythroblastic islands are observed, and the number of F4/80-positive macrophages is substantially reduced. Those present lack cytoplasmic projections and are unable to interact with erythroblasts. Interestingly, wild type macrophages can bind Emp-deficient erythroblasts, but these erythroblasts do not extrude their nuclei, suggesting that Emp impacts enucleation in a cell autonomous fashion. Previous studies have implicated the actin cytoskeleton and its reorganization in both erythroblast enucleation as well as in macrophage development. We demonstrate that Emp associates with F-actin and that this interaction is important in the normal distribution of F-actin in both erythroblasts and macrophages. Thus, Emp appears to be required for erythroblast enucleation and in the development of the mature macrophages. The availability of an Emp null model provides a unique experimental system to study the enucleation process and to evaluate the function of macrophages in definitive erythropoiesis.
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Affiliation(s)
- Shivani Soni
- Department of Medicine, Center for Cell Biology, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02135, USA
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18
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Bala S, Kumar A, Soni S, Sinha S, Hanspal M. Emp is a component of the nuclear matrix of mammalian cells and undergoes dynamic rearrangements during cell division. Biochem Biophys Res Commun 2006; 342:1040-8. [PMID: 16510120 DOI: 10.1016/j.bbrc.2006.02.060] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 02/10/2006] [Indexed: 11/29/2022]
Abstract
Emp, originally detected in erythroblastic islands, is expressed in numerous cell types and tissues suggesting a functionality not limited to hematopoiesis. To study the function of Emp in non-hematopoietic cells, an epitope-tagged recombinant human Emp was expressed in HEK cells. Preliminary studies revealed that Emp partitioned into both the nuclear and Triton X-100-insoluble cytoskeletal fractions in approximately a 4:1 ratio. In this study, we report investigations of Emp in the nucleus. Sequential extractions of interphase nuclei showed that recombinant Emp was present predominantly in the nuclear matrix. Immunofluorescence microscopy showed that Emp was present in typical nuclear speckles enriched with the spliceosome assembly factor SC35 and partially co-localized with actin staining. Coimmunoprecipitation and GST-pull-down assays confirmed the apparent close association of Emp with nuclear actin. During mitosis, Emp was detected at the mitotic spindle/spindle poles, as well as in the contractile ring during cytokinesis. These results suggest that Emp undergoes dynamic rearrangements within the nuclear architecture that are correlated with cell division.
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Affiliation(s)
- Shashi Bala
- Center of Cell Biology, Department of Medicine, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135, USA
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19
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Krauss SW, Lo AJ, Short SA, Koury MJ, Mohandas N, Chasis JA. Nuclear substructure reorganization during late-stage erythropoiesis is selective and does not involve caspase cleavage of major nuclear substructural proteins. Blood 2005; 106:2200-5. [PMID: 15933051 PMCID: PMC1895142 DOI: 10.1182/blood-2005-04-1357] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Enucleation, a rare feature of mammalian differentiation, occurs in 3 cell types: erythroblasts, lens epithelium, and keratinocytes. Previous investigations suggest that caspase activation functions in lens epithelial and keratinocyte enucleation, as well as in early erythropoiesis encompassing erythroid burst-forming unit (BFU-E) differentiation to proerythroblast. To determine whether caspase activation contributes to later erythropoiesis and whether nuclear substructures other than chromatin reorganize, we analyzed distributions of nuclear subcompartment proteins and assayed for caspase-induced cleavage of subcompartmental target proteins in mouse erythroblasts. We found that patterns of lamin B in the filamentous network interacting with both the nuclear envelope and DNA, nuclear matrix protein NuMA (Nuclear mitotic apparatus), and splicing factors Sm and SC35 persisted during nuclear condensation, consistent with effective transcription of genes expressed late in differentiation. Thus, nuclear reorganization prior to enucleation is selective, allowing maintenance of critical transcriptional processes independent of extensive chromosomal reorganization. Consistent with these data, we found no evidence for caspase-induced cleavage of major nuclear subcompartment proteins during late erythropoiesis, in contrast to what has been observed in early erythropoiesis and in lens epithelial and keratinocyte differentiation. These findings imply that nuclear condensation and extrusion during terminal erythroid differentiation involve novel mechanisms that do not entail major activation of apoptotic machinery.
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Affiliation(s)
- Sharon Wald Krauss
- Life Sciences Division, University of California Lawrence Berkeley National Laboratory, Bldg 74, 1 Cyclotron Rd, Berkeley, CA 94720, USA
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20
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Fornas O, Domingo JC, Marin P, Petriz J. Flow cytometric-based isolation of nucleated erythroid cells during maturation: an approach to cell surface antigen studies. CYTOMETRY 2002; 50:305-12. [PMID: 12497592 DOI: 10.1002/cyto.10158] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nucleated red blood cells (NRBCs) are involved in normal physiologic processes, as well as in several malignancies. They are usually counted manually under the microscope. However, blood sample manipulation may be a source of variability and manual counting is imprecise, time-consuming, and subjective. To improve identification of CD45-negative cells, we used a flow cytometry technique that avoids the addition of lysing reagents and stains viable cell nuclei. We applied this method for counting and isolating NRBC subpopulations in whole blood samples, using DNA/RNA viable staining to discriminate nonnucleated erythroid cells and debris. NRBC counts gave 197.95 cells per mm(3) in mobilized peripheral blood samples (1.00%, n = 20), 3897.59 cells per mm(3) in leukapheresis products (3.08%, n = 20), and 765.21 cells per mm(3) in cord blood samples (6.09%, n = 20). Normal bone marrow counts were 5449.42 cells per mm(3) (11.76%, n = 20). Scatter profiles showed three distinct populations, from early to late-stage erythroblasts, consisting of erythroblasts, orthochromatic erythroblasts, and ejected nuclei, as confirmed by Wright-Giemsa staining. In addition, flow cytometry immunophenotyping showed that glycophorin A was expressed dimly on NRBCs during maturation. These findings point to the feasibility of live NRBCs studies, which offer great potential for a wide range of disciplines.
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Affiliation(s)
- Oscar Fornas
- Department of Hematotherapy, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain
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21
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Chen CY, Pajak L, Tamburlin J, Bofinger D, Koury ST. The effect of proteasome inhibitors on mammalian erythroid terminal differentiation. Exp Hematol 2002; 30:634-9. [PMID: 12135659 DOI: 10.1016/s0301-472x(02)00826-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Murine erythroblasts infected with the anemia-inducing strain of Friend virus (FVA cells) terminally differentiate to the reticulocyte stage after 48 hours of culture in vitro in response to erythropoietin (EPO). The objective of this study was to determine the possible role of proteasome-mediated proteolysis during the terminal differentiation of FVA cells. MATERIALS AND METHODS The proteasome inhibitors MG132 and lactacystin were used to perturb the normal function of proteasomes during terminal differentiation. Effects of proteasome inhibitors on terminal differentiation were quantitated by evaluation of cellular morphology after benzidine staining and by Western blot analyses. RESULTS Treatment of EPO-stimulated FVA cells with lactacystin or MG132 at later periods of culture increased accumulations of nuclear and cytosolic ubiquitinated proteins and decreased nuclear extrusion to less than 40% of controls. CONCLUSIONS Our results suggest that the proteasomal degradation of ubiquitinated proteins plays an important role in the enucleation of mammalian erythroblasts.
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Affiliation(s)
- Cheng Yao Chen
- Department of Biotechnical and Clinical Laboratory Sciences, State University of New York at Buffalo, Buffalo, NY, USA
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22
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Sonoda Y, Sasaki K, Suda M, Itano C, Iwatsuki H. Effects of colchicine on the enucleation of erythroid cells and macrophages in the liver of mouse embryos: ultrastructural and three-dimensional studies. Anat Rec (Hoboken) 1998; 251:290-6. [PMID: 9669755 DOI: 10.1002/(sici)1097-0185(199807)251:3<290::aid-ar3>3.0.co;2-#] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Enucleation is the last event in the development of a definitive erythroid line, and extruded nuclei are phagocytosed by macrophages. Both colchicine and cytochalasin have been known to exert a great influence on the enucleation process, but the relationship between enucleation and these agents has not yet been clearly revealed in vivo. Our aim was to clarify the significance of the enucleation in liver erythropoiesis and macrophage phagocytosis by colchicine and cytochalasin administration to embryonic mice. Pregnant mice were intraperitoneally injected with colchicine or cytochalasin at 13 days of gestation. Embryonic livers were removed at intervals of 3, 6 and 12 h after injection for processing for light and electron microscopy, and, to obtain three-dimensional morphology of erythroids at enucleation, computer-aided reconstructions were performed by light microscopy. Colchicine injections had cytolytic effects on hepatocytes and macrophages, and numerous erythroblasts were observed in the process of enucleation after colchicine injection. However, the extruding nuclei were irregularly shaped, and some erythroblasts at mitosis showed extreme peripheralization of their chromosomal masses and cell membrane constriction. Enucleation behavior could also be observed in immature erythroblasts. Liver macrophages engulfed extruded nuclei and erythroblasts in mitosis. Cytochalasin injections, on the other hand, had no significant effect on embryonic livers. The progress of erythroblast mitosis was clearly stopped by colchicine injection, and numerous erythroblasts at mitosis were extruding their nuclear compartment. Following colchicine injection, erythroid enucleation also took place in immature erythroblasts, and mitotic erythroids were phagocytosed. In enucleation, more attention should be paid to hematopoietic environmental factors than to hemopoietic cell factors.
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Affiliation(s)
- Y Sonoda
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Japan.
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23
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Merry NE, Johnson MH, Gehring CA, Selwood L. Cytoskeletal organization in the oocyte, zygote, and early cleaving embryo of the stripe-faced dunnart (Sminthopsis macroura). Mol Reprod Dev 1995; 41:212-24. [PMID: 7654375 DOI: 10.1002/mrd.1080410212] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ovulation occurs in Sminthopsis macroura approximately 160 hr after administration of 1.3 IU PMSG, and yields significantly more oocytes than does spontaneous ovulation (P = 0.001). Germinal vesicle (GV)-stage oocytes have a thin cortical rim of microfilaments, which is disrupted by exposure to cytochalasin D. After GV breakdown, the first meiotic spindle forms subcortically and parallel to the oolemma. It rotates during anaphase and telophase to extrude the first polar body. This rotation is associated with a local cortical concentration of microfilaments, which is extruded in the first polar body. The second meiotic spindle is orthogonal to the surface, and extrusion of the second polar body is not associated with obvious local changes in cortical actin, resulting in a polar body containing little polymerized actin. The sites of second polar body emission and sperm entry are always in the half of the oocyte opposite the concentrating yolk mass, and are within 60 degrees of each other in most oocytes. During the concentration and eccentric movement of the yolk, microfilaments condense around it. During yolk expulsion, these microfilaments become continuous with those located subcortically. During early cleavage, the cytocortex of the zygote, but not of the extruded yolk mass, stains heavily for polymerised actin. Multiple sites of pericentriolar material are detectable in the cytoplasm of some secondary unfertilized oocytes which, in the presence of taxol, generate large cytasters and pseudospindle structures. After fertilization, a large aster is formed in association with the sperm entry point and serves as the center of an extensive cytoplasmic network of microtubules which surrounds but does not enter the yolk mass. Taxol treatment generates small cytasters within this meshwork and promotes selective stabilization of some periyolk microtubules opposite to the sperm aster.
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Affiliation(s)
- N E Merry
- School of Zoology, La Trobe University, Bundoora, Victoria, Australia
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24
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Bethlenfalvay NC, Lima JE, Banks RE. The effect of enzyme replacement on red cell adenine deoxyribonucleotides in adenosine deaminase-deficient erythrocytes of the opossum, Didelphis virginiana. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1993; 106:635-9. [PMID: 8281757 DOI: 10.1016/0305-0491(93)90141-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. Polyethyleneglycol-modified bovine adenosine deaminase was administered (10-20 U/kg/week) intramuscularly to two opossums for 15 weeks and changes in red cell adenine ribo- and deoxyribonucleotides quantitated by HPLC. 2. Only a moderate decline of erythrocyte dAXP was observed at the end of the study when compared to results of enzyme replacement seen in human adenosine deaminase deficient patients. 3. Opossum red cells salvage substantial amounts of deoxyadenosine provided in physiologic (50 nM) concentration from plasma having either low or high adenosine deaminase activity.
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Affiliation(s)
- N C Bethlenfalvay
- Department of Primary Care, Fitzsimons Army Medical Center, Aurora, CO 80045
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25
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Brunner Júnior A, de Rizzo E, Morena DD, Cianciarullo AM, Jared C, Morena P. Hemosomegenesis and hemoglobin biosynthesis in vertebrates. ACTA ACUST UNITED AC 1992; 102:645-64. [PMID: 1355029 DOI: 10.1016/0300-9629(92)90718-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
1. Ultrastructural observations on maturing rabbit embryo erythroid cells led to the finding of hemoglobinized organelles distinguishable from mitochondria due to their highly dense matrix, two or three longitudinally arranged double lamellae, and smaller diameters. Intraorganellar 50-60 A particles identical to those contained in the hemoglobinized cytoplasm were found. 2. Their hemoglobin (Hb) content was demonstrated by electrophoresis of the concentrated supernatant from the isolated, washed, and osmotically lysed organellar fraction. We have proposed that these organelles are the sites for heme integration into the globin (G) polypeptide chains and subunits assembly. The term hemosome has been suggested for such entities. 3. This hypothesis has been sustained by several analytical and experimental works based on the postulation that hemosomes should be found at higher frequencies where the Hb biosynthesis rate is more intensive, or where the induction of this biosynthesis is always dependent on the formation of hemosomes. 4. Maturing erythroid cells of the circulating embryo blood contain hemosomes in higher frequency than in liver erythroid cells, coinciding with the higher Hb biosynthesis rate in peripheral blood than in the liver. In bleeding anemia, the decay of Hb concentration parallels the reduction of the mean number of hemosomes per reticulocyte, in comparison with normal reticulocytes. 5. In HeLa cells and epithelial cultured cells induced to synthesize Hb, it was shown that this biosynthesis is ever concomitant with the formation of hemosomes and depends on the presence of erythropoietin, as occurs in erythroid cells. 6. Studies on hemosomegenesis and Hb biosynthesis experimentally effected in epithelial cultured cells, allowed the interpretation of the sequence of events leading to hemosome formation in maturing erythroid cells. Simultaneously with iron uptake, mitochondria differentiate to lamellated bodies and, successively, expansions rise for ferruginous compounds and G polypeptides gathering, followed by prehemosome vesicles formation, which condense and change to prohemosomes that afterwards evolve to hemosomes. 7. These dynamics, and organellar Hb have been detected in immature erythrocytes of mammalians, including humans, avians, reptilians, amphibians and representative fish specimens. It appears that these events occur in the erythrocytary maturation of all vertebrate classes.
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Affiliation(s)
- A Brunner Júnior
- Laboratories of Electron Microscopy, Instituto Butantan, São Paulo, Brasil
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26
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Koury ST, Koury MJ, Bondurant MC. Cytoskeletal distribution and function during the maturation and enucleation of mammalian erythroblasts. J Cell Biol 1989; 109:3005-13. [PMID: 2574178 PMCID: PMC2115945 DOI: 10.1083/jcb.109.6.3005] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have used murine splenic erythrolasts infected with the anemia-inducing strain of Friend virus (FVA cells), as an in vitro model to study cytoskeletal elements during erythroid maturation and enucleation. FVA cells are capable of enucleating in suspension culture in vitro, indicating that associations with an extracellular matrix or accessory cells are not required for enucleation to occur. The morphology of FVA cells undergoing enucleation is nearly identical to erythroblasts enucleating in vivo. The nucleus is segregated to one side of the cell and then appears to be pinched off resulting in an extruded nucleus and reticulocyte. The extruded nucleus is surrounded by an intact plasma membrane and has little cytoplasm associated with it. Newly formed reticulocytes have an irregular shape, are vacuolated and contain all cytoplasmic organelles. The spatial distribution of several cytoskeletal proteins was examined during the maturation process. Spectrin was found associated with the plasma membrane of FVA cells at all stages of maturation but was segregated entirely to the incipient reticulocyte during enucleation. Microtubules formed cages around nuclei in immature FVA cells and were found primarily in the incipient reticulocyte in cells undergoing enucleation. Reticulocytes occasionally contained microtubules, but a generalized diffuse distribution of tubulin was more common. Vimentin could not be detected at any time in FVA cell maturation. Filamentous actin (F-actin) had a patchy distribution at the cell surface in the most immature erythroblasts, but F-actin bundles could be detected as the cells matured. F-actin was found concentrated between the extruding nucleus and incipient reticulocyte in enucleating erythroblasts. Newly formed reticulocytes exhibited punctate actin fluorescence whereas extruded nuclei lacked F-actin. Addition of colchicine, vinblastine, or taxol to cultures of FVA cells did not affect enucleation. In contrast, cytochalasin D caused a complete inhibition of enucleation that could be reversed by washing out the cytochalasin D. These results demonstrate that F-actin plays a role in enucleation while the complete absence of microtubules or excessive numbers of polymerized microtubules do not affect enucleation.
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Affiliation(s)
- S T Koury
- Vanderbilt University, Nashville, Tennessee
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27
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Abstract
Bone-marrow macrophages from both rat and mouse release deoxycytidine derived from phagocytosed nuclei. Mouse plasma contains no detectable deoxycytidine (less than 0.1 microM), whereas the concentration in rat plasma is 18 microM. Enzyme assays of tissue extracts show that both mouse and rat spleen contain high deoxycytidine kinase activity. Mouse organs, including kidney, liver and lung, also have deoxycytidine deaminase activity. In contrast, rat tissues have virtually no deoxycytidine deaminase activity. Lack of deaminase provides an explanation for the presence of deoxycytidine in rat plasma. Cytotoxicity assays show that cultured mouse lymphoid cells grown in undialysed rat serum are more resistant to cytotoxic effects of deoxyadenosine than are those cells grown in dialysed rat serum. The results suggest that a major difference in deoxycytidine metabolism between mouse and rat may account for discrepancies in the pharmacological response of the two animals to certain nucleoside compounds.
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29
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Skutelsky E, Bayer EA. Cell-type-related segregation of surface galactosyl-containing components at an early developmental stage in hemopoietic bone marrow cells in the rabbit. J Cell Biol 1983; 96:184-90. [PMID: 6826646 PMCID: PMC2112270 DOI: 10.1083/jcb.96.1.184] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The avidin-biotin complex was used for the selective ultrastructural labeling of terminal cell surface galactosyl residues. Rabbit bone marrow cells were treated with the enzyme galactose oxidase in the presence of biotin hydrazide. Subsequent treatment with ferritin-avidin conjugates enabled the electron microscopic visualization of terminal membrane-based galactose and/or N-acetylgalactosamine on these cells. All stages of erythroid development were characterized by high levels of exposed cell surface galactose, whereas all leukoid cells in the same preparations were virtually unlabeled by the above method. Modulations in the distribution of these surface determinants during differentiation and maturation of rabbit erythroid cells were found to concur in inverse fashion with respect to that of terminal sialic acids. Neuraminidase treatment, before the above labeling procedure, resulted in the exposure of additional galactosyl residues on the surface of all bone marrow cell types. The results indicate that a galactose-bearing glycoconjugate(s) may comprise an erythroid-specific membrane constituent of rabbit bone marrow cells. The high density of galactose on the surface of even the earliest erythroid precursors may eventually enable the identification and isolation of a stem cell, which already contains the erythroid-specific galactoconjugate(s). The results suggest that variations in the spectrum of cell surface carbohydrates may serve as recognition signals in the complex set of intercellular interactions which occur during the development and maturation of the erythrocyte. The occurrence of similar but species-specific variations in the complement of surface heterosaccharides during erythroid development of humans and other mammals supports this contention.
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30
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Chan TS, Lakhchaura BD. Deoxycytidine excretion by mouse peritoneal macrophages: its implication in modulation of immunological functions. J Cell Physiol 1982; 111:28-32. [PMID: 7085768 DOI: 10.1002/jcp.1041110106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Pyrimidine excretion by macrophages was studied in order to identify the potential immunoregulatory effector molecules. Deoxycytidine was found in the culture medium of thioglycollate-elicited mouse peritoneal macrophages, along with thymidine, which was shown by others to be a possible immunoregulatory substance. The identification of deoxycytidine was based on: (1) cochromatography with the authentic compound in four different solvents, (2) UV absorption spectral analysis, and (3) the enzymatic peak shift method. Phagocytosis of nucleated chicken erythrocytes, but not enucleated sheep erythrocytes, increased deoxycytidine excretion. The macrophages lacked both deoxycytidine kinase and deoxycytidine deaminase, which is consistent with their excretory pattern. Since it has been known that deoxycytidine can protect cells against cytotoxic effects of thymidine, we propose that deoxycytidine has a role in preventing immunosuppression by thimidine. In patients with adenosine deaminase deficiency, however, immunosuppression caused by combined toxicity of thymidine and deoxyadenosine may not be adequately prevented by deoxycytidine.
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31
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Repasky EA, Eckert BS. The effect of cytochalasin B on the enucleation of erythroid cells in vitro. Cell Tissue Res 1981; 221:85-91. [PMID: 7198511 DOI: 10.1007/bf00216572] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The process of nuclear extrusion continues when erythroid cells of mouse spleen are placed in vitro, although the process may be considerably retarded. This allows visualization of unusually large numbers of enucleating cells after 30 min in vitro. With this system, the mechanism of enucleation can be analyzed both qualitatively and quantitatively. We have used this system to study the effects of cytochalasin B and have found it to be a potent inhibitor of enucleation. These results suggest that microfilaments are involved in the process of enucleation.
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32
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Geyer G, Linss W, Meyer HW, Makovitzky J, Feuerstein H, Stibenz D. Alteration of the enucleating erythroblast glycocalyx. Acta Histochem 1979; 64:26-36. [PMID: 112825 DOI: 10.1016/s0065-1281(79)80048-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Plasmalemmal differentiation of the enucleating normoblast of rabbit and rat was studied by means of cytochemical methods and freeze-etching. Staining with colloidal iron revealed about identical amounts of iron particles bound to various areas of the normoblast membrane. Cationized ferritin and ruthenium red, likewise, failed in the demonstration of significant changes of the enucleating normoblast glycocalyx. Despite these findings the topo-optical staining with toluidine blue showed the plasmalemmal envelope of the protruding normoblast nucleus moderately birefringent, clearly discriminated from the intense anisotropic staining of the future reticulocyte membrane. The ferritin-labeled snail lectin anti AHP localized a great number of binding sites at the plasmalemmal envelope of the nucleus under extrusion. That is in sharp contrast with rather low lectin binding to the future reticulocyte membrane which amounts to about 30 to 50% of the nuclear envelope label. The findings provide evidence of unmasking of bindings sites of the normoblast membrane. Apparently, the effect is due to conformational changes of the cell membrane, rather than it could be attributed to degradation of glycoproteins. Moreover, enucleation kinetics may also be related to supramolecular changes of membrane structure albeit missing evidence for the rearrangement of membrane particles.
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Affiliation(s)
- R D Alsaker
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota 55108
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Brunner A, Mitsutani CY, de Araújo Peres C. Comparative ultrastructure of late rabbit-embryo erythroid cells in liver and peripheral blood. Am J Hematol 1977; 2:227-36. [PMID: 596367 DOI: 10.1002/ajh.2830020304] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A morphological study of hemoglobin biosynthesis activity in rabbit-embryo liver and peripheral blood was comparatively developed. Orthochromatic erythroblasts and reticulocytes of the same maturing degree were analysed through thin sections, as to their organellar constitution and behaviour regarding iron incorporation. It was found that peripheral blood erythroid cells contain mainly hemosomes, organelles taken as sites of final hemoglobin molecule biosynthesis. The ratio between the mean number of hemosomes in blood erythroid cell sections and that in liver erythroid cell sections reaches a little more than 6:1. Inversely, late liver erythroid cells are predominantly constituted by mitochondria that directly or indirectly participate in hemosome formation. The ratio between the mean number of mitochondria in blood erythroid cell sections and that in liver erythroid cell sections reaches 1:11. Besides this, the iron incorporation activity is higher in peripheral blood erythroid cells than in liver erythroblasts and reticulocytes. It is apparent that erythroid cells in the liver accumulate heme, given the ratio of the means of iron incorporation activity per cell to hemosome per cell (3.67), while blood erythroid cells, with a 1.08 ratio, synthesize heme, which is immediately afterwards integrated into the globin chains. The sudden increase in the formation of hemosomes when liver orthochromatic erythroblasts and reticulocytes enter the peripheral blood, reflecting an enhancement of hemoglobin synthesis, agrees with biochemical findings of other authors.
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Skutelsky E, Farquhar MG. Variations in distribution of con A receptor sites and anionic groups during red blood cell differentiation in the rat. J Cell Biol 1976; 71:218-31. [PMID: 977648 PMCID: PMC2109729 DOI: 10.1083/jcb.71.1.218] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The distribution of receptors for concanavalin A (Con A) and anionic groups on plasma membranes of developing blood cells was investigated in the rat. Glutaraldehyde-fixed bone marrow and circulating blood cells were exposed to ferritin-conjugated Con A or positively chaged ferric oxide (CI) and processed for electro n microscopy. The frequency of Con A and CI binding sites varied during different erythroid developmental stages and amont different leukoid cell types. There was a constant inverse relationship between Con A and CI binding sites. Among leukoid cells, Con A binding was high on plasma cells and macrophages, lower on neutrophils and lymphocytes, and still lower on eosinophils and basophils; CI binding was highest in the latter and lowest in plasma cells and macrophages. Among erythroid cells, there was a progressive increase in Con A and a decrease in CI binding after successive divisions of erythroblasts, and a progressive decrease in Con A and an increase in CI binding upon maturation of the orthochromatic erythroblast to the reticulocyte. The most pronounced modification in distribution of these sites occurred during nuclear expulsion: that protion of the plasma membrane surrounding the extruded nucleus was heavily labeled by Con A (up to four times that of the orthochromatic erythroblast) whereas the reticulocyte had considerably fewer sites. The situation was reversed with CI. The results suggest that the concentration of nonsialated glycoproteins (to which Con A binds) varies inversely to that of sialoproteins (to which CI binds) in the membrane of the differentiating erythroid cell. The remarkable changes observed at the time of nuclear extrusion suggest that there is either local modification of glycosylated groups with removal of sialyl residues from the membrane surrounding the extruded nucleus of selective segregation of membrane glycoproteins leading to a high concentration of sialoproteins (glycophroin) in the membrane of the mature erythrocyte.
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Skutelsky E, Marikovsky Y, Danon D. Immunoferitin analysis of membrane antigen density: A. Young and old human blood cells B. Developing erythroid cells and extruded erythroid nuclei. Eur J Immunol 1974; 4:512-8. [PMID: 4213169 DOI: 10.1002/eji.1830040713] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Skutelsky E, Danon D. On the expulsion of the erythroid nucleus and its phagocytosis. Anat Rec (Hoboken) 1972; 173:123-6. [PMID: 5028062 DOI: 10.1002/ar.1091730111] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Verwilghen RL, Tan P, De Wolf-Peeters C, Louwagie AC. Cell membrane anomaly impeding cell division. EXPERIENTIA 1971; 27:1467-8. [PMID: 5144868 DOI: 10.1007/bf02154294] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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