101
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Fleury M, Eliades A, Carlsson P, Lacaud G, Kouskoff V. FOXF1 inhibits hematopoietic lineage commitment during early mesoderm specification. Development 2015; 142:3307-20. [PMID: 26293303 DOI: 10.1242/dev.124685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022]
Abstract
The molecular mechanisms orchestrating early mesoderm specification are still poorly understood. In particular, how alternate cell fate decisions are regulated in nascent mesoderm remains mostly unknown. In the present study, we investigated both in vitro in differentiating embryonic stem cells, and in vivo in gastrulating embryos, the lineage specification of early mesodermal precursors expressing or not the Forkhead transcription factor FOXF1. Our data revealed that FOXF1-expressing mesoderm is derived from FLK1(+) progenitors and that in vitro this transcription factor is expressed in smooth muscle and transiently in endothelial lineages, but not in hematopoietic cells. In gastrulating embryos, FOXF1 marks most extra-embryonic mesoderm derivatives including the chorion, the allantois, the amnion and a subset of endothelial cells. Similarly to the in vitro situation, FOXF1 expression is excluded from the blood islands and blood cells. Further analysis revealed an inverse correlation between hematopoietic potential and FOXF1 expression in vivo with increased commitment toward primitive erythropoiesis in Foxf1-deficient embryos, whereas FOXF1-enforced expression in vitro was shown to repress hematopoiesis. Altogether, our data establish that during gastrulation, FOXF1 marks all posterior primitive streak extra-embryonic mesoderm derivatives with the remarkable exception of the blood lineage. Our study further suggests that this transcription factor is implicated in actively restraining the specification of mesodermal progenitors to hematopoiesis.
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Affiliation(s)
- Maud Fleury
- Cancer Research UK Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Alexia Eliades
- Cancer Research UK Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Peter Carlsson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg 40530, Sweden
| | - Georges Lacaud
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Valerie Kouskoff
- Cancer Research UK Stem Cell Hematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
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102
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Bmi-1 Regulates Extensive Erythroid Self-Renewal. Stem Cell Reports 2015; 4:995-1003. [PMID: 26028528 PMCID: PMC4471833 DOI: 10.1016/j.stemcr.2015.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 05/01/2015] [Accepted: 05/04/2015] [Indexed: 11/29/2022] Open
Abstract
Red blood cells (RBCs), responsible for oxygen delivery and carbon dioxide exchange, are essential for our well-being. Alternative RBC sources are needed to meet the increased demand for RBC transfusions projected to occur as our population ages. We previously have discovered that erythroblasts derived from the early mouse embryo can self-renew extensively ex vivo for many months. To better understand the mechanisms regulating extensive erythroid self-renewal, global gene expression data sets from self-renewing and differentiating erythroblasts were analyzed and revealed the differential expression of Bmi-1. Bmi-1 overexpression conferred extensive self-renewal capacity upon adult bone-marrow-derived self-renewing erythroblasts, which normally have limited proliferative potential. Importantly, Bmi-1 transduction did not interfere with the ability of extensively self-renewing erythroblasts (ESREs) to terminally mature either in vitro or in vivo. Bmi-1-induced ESREs can serve to generate in vitro models of erythroid-intrinsic disorders and ultimately may serve as a source of cultured RBCs for transfusion therapy. Bmi-1 promotes the extensive self-renewal of adult murine erythroblasts Transfusion of iESRE leads to fully mature RBCs that circulate for 6–7 weeks in vivo
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103
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Histone methyltransferase Setd8 represses Gata2 expression and regulates erythroid maturation. Mol Cell Biol 2015; 35:2059-72. [PMID: 25848090 DOI: 10.1128/mcb.01413-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/27/2015] [Indexed: 11/20/2022] Open
Abstract
Setd8 is the sole histone methyltransferase in mammals capable of monomethylating histone H4 lysine 20 (H4K20me1). Setd8 is expressed at significantly higher levels in erythroid cells than any other cell or tissue type, suggesting that Setd8 has an erythroid-cell-specific function. To test this hypothesis, stable Setd8 knockdown was established in extensively self-renewing erythroblasts (ESREs), a well-characterized, nontransformed model of erythroid maturation. Knockdown of Setd8 resulted in impaired erythroid maturation characterized by a delay in hemoglobin accumulation, larger mean cell area, persistent ckit expression, incomplete nuclear condensation, and lower rates of enucleation. Setd8 knockdown did not alter ESRE proliferation or viability or result in accumulation of DNA damage. Global gene expression analyses following Setd8 knockdown demonstrated that in erythroid cells, Setd8 functions primarily as a repressor. Most notably, Gata2 expression was significantly higher in knockdown cells than in control cells and Gata2 knockdown rescued some of the maturation impairments associated with Setd8 disruption. Setd8 occupies critical regulatory elements in the Gata2 locus, and knockdown of Setd8 resulted in loss of H4K20me1 and gain of H4 acetylation at the Gata2 1S promoter. These results suggest that Setd8 is an important regulator of erythroid maturation that works in part through repression of Gata2 expression.
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104
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Siatecka M, Soni S, Planutis A, Bieker JJ. Transcriptional activity of erythroid Kruppel-like factor (EKLF/KLF1) modulated by PIAS3 (protein inhibitor of activated STAT3). J Biol Chem 2015; 290:9929-40. [PMID: 25713074 DOI: 10.1074/jbc.m114.610246] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Indexed: 01/12/2023] Open
Abstract
Erythroid Kruppel-like factor (EKLF or KLF1) is a transcription factor crucial for red cell development that is directly involved in regulation of a large number of erythroid genes. EKLF serves mostly as an activator of expression of these genes; however, it can act also as a repressor. Here, we present evidence that EKLF interacts with proteins from the PIAS (protein inhibitor of activated STAT) family that convey repressive activity to EKLF in the absence of sumoylation. Our studies identify PIAS3 as a transcriptional corepressor of EKLF for at least a subset of its target genes during erythropoiesis (e.g. β-globin, α-hemoglobin stabilizing protein). We demonstrate an interaction between EKLF and PIAS proteins confirmed by in vivo coimmunoprecipitation assays with both exogenous and endogenous proteins. We identified an LXXLL signature motif located near the N terminus of PIAS proteins that, although not involved in the EKLF-PIAS3 interaction, is required for the transrepression activity. Knockdown of endogenous PIAS3 accelerates differentiation of both murine erythroleukemia cells, as well as fetal liver cells, whereas an increase in PIAS3 levels inhibits this increase. Using chromatin immunoprecipitation assays, we show that PIAS3 preferentially occupies the β-globin promoter in undifferentiated murine erythroleukemia cells. Together these results demonstrate that an interaction between EKLF and PIAS3 provides a novel mode of regulation of EKLF activity in the absence of sumolylation and furthermore shows an important involvement of PIAS proteins in erythropoiesis.
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Affiliation(s)
- Miroslawa Siatecka
- From the Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, New York 10029 and the Department of Genetics, Institute of Experimental Biology, University of Adam Mickiewicz, 61-614 Poznan, Poland
| | - Shefali Soni
- From the Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, New York 10029 and
| | - Antanas Planutis
- From the Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, New York 10029 and
| | - James J Bieker
- From the Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, New York 10029 and
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105
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Abstract
PURPOSE OF REVIEW This review will provide an overview of the translational regulation of globin mRNAs and integrated stress response (ISR) during erythropoiesis by heme-regulated eIF2α kinase (HRI). HRI is an intracellular heme sensor that coordinates heme and globin synthesis in erythropoiesis by inhibiting protein synthesis of globins and heme biosynthetic enzymes during heme deficiency. RECENT FINDINGS It has been demonstrated recently that HRI also activates the eIF2αP-activating transcription factor 4 (ATF4) ISR in primary erythroid precursors to combat oxidative stress. During chronic iron/heme deficiency in vivo, this HRI-eIF2αP-ATF4 signaling is necessary both to reduce oxidative stress and to promote erythroid differentiation. Augmenting eIF2αP signaling by the small molecule salubrinal, which inhibits dephosphorylation of eIF2αP, reduces excess α-globin synthesis and enhances translation of ATF4 mRNA in mouse β-thalassemic erythroid precursors. Intriguingly, salubrinal treatment of differentiating human CD34⁺ cells in culture increases fetal hemoglobin production with a concomitant decrease of adult hemoglobin by a posttranscriptional mechanism. SUMMARY HRI-eIF2αP-ATF4 stress signaling is important not only to inhibit excess globin synthesis during erythropoiesis, but is also critical for adaptation to oxidative stress and for enhancing effective erythropoiesis. Modulation of this signaling pathway with small chemicals may provide a novel therapy for hemoglobinopathy.
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106
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Ulirsch JC, Lacy JN, An X, Mohandas N, Mikkelsen TS, Sankaran VG. Altered chromatin occupancy of master regulators underlies evolutionary divergence in the transcriptional landscape of erythroid differentiation. PLoS Genet 2014; 10:e1004890. [PMID: 25521328 PMCID: PMC4270484 DOI: 10.1371/journal.pgen.1004890] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/13/2014] [Indexed: 12/20/2022] Open
Abstract
Erythropoiesis is one of the best understood examples of cellular differentiation. Morphologically, erythroid differentiation proceeds in a nearly identical fashion between humans and mice, but recent evidence has shown that networks of gene expression governing this process are divergent between species. We undertook a systematic comparative analysis of six histone modifications and four transcriptional master regulators in primary proerythroblasts and erythroid cell lines to better understand the underlying basis of these transcriptional differences. Our analyses suggest that while chromatin structure across orthologous promoters is strongly conserved, subtle differences are associated with transcriptional divergence between species. Many transcription factor (TF) occupancy sites were poorly conserved across species (∼25% for GATA1, TAL1, and NFE2) but were more conserved between proerythroblasts and cell lines derived from the same species. We found that certain cis-regulatory modules co-occupied by GATA1, TAL1, and KLF1 are under strict evolutionary constraint and localize to genes necessary for erythroid cell identity. More generally, we show that conserved TF occupancy sites are indicative of active regulatory regions and strong gene expression that is sustained during maturation. Our results suggest that evolutionary turnover of TF binding sites associates with changes in the underlying chromatin structure, driving transcriptional divergence. We provide examples of how this framework can be applied to understand epigenomic variation in specific regulatory regions, such as the β-globin gene locus. Our findings have important implications for understanding epigenomic changes that mediate variation in cellular differentiation across species, while also providing a valuable resource for studies of hematopoiesis. The process whereby blood progenitor cells differentiate into red blood cells, known as erythropoiesis, is very similar between mice and humans. Yet, while studies of this process in mouse have substantially improved our knowledge of human erythropoiesis, recent work has shown a significant divergence in global gene expression across species, suggesting that extrapolation from mouse models to human is not always straightforward. In order to better understand these differences, we have performed a comparative epigenomic analysis of six histone modifications and four master transcription factors. By globally comparing chromatin structure across primary cells and model cell lines in both species, we discovered that while chromatin structure is well conserved at orthologous promoters, subtle changes are predictive of species-specific gene expression. Furthermore, we discovered that the genomic localizations of master transcription factors are poorly conserved, and species-specific losses or gains are associated with changes to the underlying chromatin structure and concomitant gene expression. By using our comparative epigenomics framework, we identified a putative human-specific cis-regulatory module that drives expression of human, but not mouse, GDF15, a gene implicated in iron homeostasis. Our results provide a resource to aid researchers in interpreting genetic and epigenetic differences between species.
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Affiliation(s)
- Jacob C. Ulirsch
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Jessica N. Lacy
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Xiuli An
- New York Blood Center, New York, New York, United States of America
| | - Narla Mohandas
- New York Blood Center, New York, New York, United States of America
| | - Tarjei S. Mikkelsen
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Harvard Stem Cell Institute, Cambridge, Massachusetts, United States of America
| | - Vijay G. Sankaran
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- * E-mail:
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107
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Chao R, Gong X, Wang L, Wang P, Wang Y. CD71(high) population represents primitive erythroblasts derived from mouse embryonic stem cells. Stem Cell Res 2014; 14:30-8. [PMID: 25485690 DOI: 10.1016/j.scr.2014.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 01/03/2023] Open
Abstract
The CD71/Ter119 combination has been widely used to reflect dynamic maturation of erythrocytes in vivo. However, because CD71 is expressed on all proliferating cells, it is unclear whether it can be utilized as an erythrocyte-specific marker during differentiation of embryonic stem cells (ESCs). In this study, we revealed that a population expressing high level of CD71 (CD71(high)) during mouse ESC differentiation represented an in vitro counterpart of yolk sac-derived primitive erythroblasts (EryPs) isolated at 8.5days post coitum. In addition, these CD71(high) cells went through "maturational globin switching" and enucleated during terminal differentiation in vitro that were similar to the yolk sac-derived EryPs in vivo. We further demonstrated that the formation of CD71(high) population was regulated differentially by key factors including Scl, HoxB4, Eaf1, and Klf1. Taken together, our study provides a technical advance that allows efficient segregation of EryPs from differentiated ESCs in vitro for further understanding molecular regulation during primitive erythropoiesis.
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Affiliation(s)
- Ruihua Chao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Xueping Gong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Libo Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Pengxiang Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yuan Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.
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108
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Abstract
Burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) cells are erythroid progenitors traditionally defined by colony assays. We developed a flow cytometry-based strategy for isolating human BFU-E and CFU-E cells based on the changes in expression of cell surface markers during in vitro erythroid cell culture. BFU-E and CFU-E are characterized by CD45(+)GPA(-)IL-3R(-)CD34(+)CD36(-)CD71(low) and CD45(+)GPA(-)IL-3R(-)CD34(-)CD36(+)CD71(high) phenotypes, respectively. Colony assays validated phenotypic assignment giving rise to BFU-E and CFU-E colonies, both at a purity of ∼90%. The BFU-E colony forming ability of CD45(+)GPA(-)IL-3R(-)CD34(+)CD36(-)CD71(low) cells required stem cell factor and erythropoietin, while the CFU-E colony forming ability of CD45(+)GPA(-)IL-3R(-)CD34(-)CD36(+)CD71(high) cells required only erythropoietin. Bioinformatic analysis of the RNA-sequencing data revealed unique transcriptomes at each differentiation stage. The sorting strategy was validated in uncultured primary cells isolated from bone marrow, cord blood, and peripheral blood, indicating that marker expression is not an artifact of in vitro cell culture, but represents an in vivo characteristic of erythroid progenitor populations. The ability to isolate highly pure human BFU-E and CFU-E progenitors will enable detailed cellular and molecular characterization of these distinct progenitor populations and define their contribution to disordered erythropoiesis in inherited and acquired hematologic disease. Our data provides an important resource for future studies of human erythropoiesis.
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109
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McIver SC, Kang YA, DeVilbiss AW, O'Driscoll CA, Ouellette JN, Pope NJ, Camprecios G, Chang CJ, Yang D, Bouhassira EE, Ghaffari S, Bresnick EH. The exosome complex establishes a barricade to erythroid maturation. Blood 2014; 124:2285-97. [PMID: 25115889 PMCID: PMC4183988 DOI: 10.1182/blood-2014-04-571083] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/25/2014] [Indexed: 12/28/2022] Open
Abstract
Complex genetic networks control hematopoietic stem cell differentiation into progenitors that give rise to billions of erythrocytes daily. Previously, we described a role for the master regulator of erythropoiesis, GATA-1, in inducing genes encoding components of the autophagy machinery. In this context, the Forkhead transcription factor, Foxo3, amplified GATA-1-mediated transcriptional activation. To determine the scope of the GATA-1/Foxo3 cooperativity, and to develop functional insights, we analyzed the GATA-1/Foxo3-dependent transcriptome in erythroid cells. GATA-1/Foxo3 repressed expression of Exosc8, a pivotal component of the exosome complex, which mediates RNA surveillance and epigenetic regulation. Strikingly, downregulating Exosc8, or additional exosome complex components, in primary erythroid precursor cells induced erythroid cell maturation. Our results demonstrate a new mode of controlling erythropoiesis in which multiple components of the exosome complex are endogenous suppressors of the erythroid developmental program.
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Affiliation(s)
- Skye C McIver
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Yoon-A Kang
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Andrew W DeVilbiss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Chelsea A O'Driscoll
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Jonathan N Ouellette
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Nathaniel J Pope
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Genis Camprecios
- Department of Developmental and Regenerative Biology, Mt. Sinai School of Medicine, New York, NY
| | - Chan-Jung Chang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY; and
| | - David Yang
- Department of Pathology, University of Wisconsin School of Medicine and Public Health, Madison WI
| | - Eric E Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY; and
| | - Saghi Ghaffari
- Department of Developmental and Regenerative Biology, Mt. Sinai School of Medicine, New York, NY
| | - Emery H Bresnick
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
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110
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The over-expression of aquaporin-1 alters erythroid gene expression in human erythroleukemia K562 cells. Tumour Biol 2014; 36:291-302. [PMID: 25252847 DOI: 10.1007/s13277-014-2614-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/09/2014] [Indexed: 10/24/2022] Open
Abstract
Aquaporin genes are differentially expressed in primitive versus definitive erythropoiesis. Our previous research results showed that over-expression of aquaporin-1 (AQP1) gene greatly promotes the erythroid differentiation of erythroleukemia K562 cells, using benzidine staining and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) analysis for representative erythroid-related genes, including γ-globin. But the molecular mechanisms underlying erythroid-specific gene regulation remain unknown. In this study, we demonstrated that AQP1 induced hemoglobins expression and altered erythroid gene expression by microarray analysis in K562 cells. The retroviral expression vector of AQP1 (pBABE-puro-AQP1) was constructed and infected K562 cells to establish a stable AQP1 over-expression cell line (K562-AQP1). AQP1 over-expression effectively inhibited cell proliferation and induced cell growth arrest in G1 phase of K562 cells. Then microarray profile was applied to analyze the differentially expressed genes which involved the mechanism of AQP1 in erythroid differentiation induction. The DAVID functional annotation clustering tool was used to identify biological functions enriched with the differentially expressed genes (n = 466 genes) and to group genes into clusters based on their functional similarity. Significant enrichment of genes involved in "oxygen transporter activity" (p = 3.8E-7) including hemoglobins (HBD, HBG, HBB, HBE1, and HBQ1), HEMGN, and EBP42 were validated by qRT-PCR. Moreover, silencing of HEMGN by RNA interference in K562-AQP1 cells resulted in down-regulation of these genes. These data provide a better understanding of the role of AQP1 in erythroid differentiation, by promoting HEMGN induction and other potential signaling pathways associated with hemoglobin induction.
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111
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Xiong Y, Yang P, Proia RL, Hla T. Erythrocyte-derived sphingosine 1-phosphate is essential for vascular development. J Clin Invest 2014; 124:4823-8. [PMID: 25250575 DOI: 10.1172/jci77685] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/08/2014] [Indexed: 12/26/2022] Open
Abstract
Transport of oxygen by red blood cells (rbc) is critical for life and embryogenesis. Here, we determined that provision of the lipid mediator sphingosine 1-phosphate (S1P) to the systemic circulation is an essential function of rbc in embryogenesis. Mice with rbc-specific deletion of sphingosine kinases 1 and 2 (Sphk1 and Sphk2) showed embryonic lethality between E11.5 and E12.5 due to defects in vascular development. Administration of an S1P1 receptor agonist to pregnant dams rescued early embryonic lethality. Even though rbc-specific Sphk1 Sphk2-KO embryos were anemic, the erythropoietic capacity of hematopoietic stem cells (HSCs) was not impaired, suggesting that rbc can develop in the absence of sphingosine kinase activity. Indeed, transplantation of HSCs deficient for Sphk1 and Sphk2 into adult mice produced rbc that lacked S1P and attenuated plasma S1P levels in recipients. However, in adult animals, both rbc and endothelium contributed to plasma S1P. Together, these findings demonstrate that rbc are essential for embryogenesis by supplying the lysophospholipid S1P, which regulates embryonic vascular development via its receptors.
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112
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Thom CS, Traxler EA, Khandros E, Nickas JM, Zhou OY, Lazarus JE, Silva APG, Prabhu D, Yao Y, Aribeana C, Fuchs SY, Mackay JP, Holzbaur ELF, Weiss MJ. Trim58 degrades Dynein and regulates terminal erythropoiesis. Dev Cell 2014; 30:688-700. [PMID: 25241935 DOI: 10.1016/j.devcel.2014.07.021] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/24/2014] [Accepted: 07/28/2014] [Indexed: 01/23/2023]
Abstract
TRIM58 is an E3 ubiquitin ligase superfamily member implicated by genome-wide association studies to regulate human erythrocyte traits. Here, we show that Trim58 expression is induced during late erythropoiesis and that its depletion by small hairpin RNAs (shRNAs) inhibits the maturation of late-stage nucleated erythroblasts to anucleate reticulocytes. Imaging flow cytometry studies demonstrate that Trim58 regulates polarization and/or extrusion of erythroblast nuclei. In vitro, Trim58 directly binds and ubiquitinates the intermediate chain of the microtubule motor dynein. In cells, Trim58 stimulates proteasome-dependent degradation of the dynein holoprotein complex. During erythropoiesis, Trim58 expression, dynein loss, and enucleation occur concomitantly, and all are inhibited by Trim58 shRNAs. Dynein regulates nuclear positioning and microtubule organization, both of which undergo dramatic changes during erythroblast enucleation. Thus, we propose that Trim58 promotes this process by eliminating dynein. Our findings identify an erythroid-specific regulator of enucleation and elucidate a previously unrecognized mechanism for controlling dynein activity.
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Affiliation(s)
- Christopher S Thom
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elizabeth A Traxler
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eugene Khandros
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jenna M Nickas
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Olivia Y Zhou
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jacob E Lazarus
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ana P G Silva
- School of Molecular Bioscience, The University of Sydney, Sydney NSW 2006, Australia
| | - Dolly Prabhu
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yu Yao
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Chiaka Aribeana
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Serge Y Fuchs
- Department of Animal Biology and Mari Lowe Comparative Oncology Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joel P Mackay
- School of Molecular Bioscience, The University of Sydney, Sydney NSW 2006, Australia
| | - Erika L F Holzbaur
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mitchell J Weiss
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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113
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Deindl P, Klar M, Drews D, Cremer M, Gammella E, Gassmann M, Dame C. Mice over-expressing human erythropoietin indicate that erythropoietin enhances expression of its receptor via up-regulated Gata1 and Tal1. Haematologica 2014; 99:e205-7. [PMID: 25085352 DOI: 10.3324/haematol.2014.104844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Philipp Deindl
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany Department of Neonatology and Pediatric Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Germany
| | - Martin Klar
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - David Drews
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Malte Cremer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Elena Gammella
- Department of Biomedical Sciences for Health, University of Milano, Italyand
| | - Max Gassmann
- Institute of Veterinary Physiology and Zurich Center for Human Integrative Physiology (ZIHP), University of Zürich, Switzerland
| | - Christof Dame
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
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Cheng AW, Shi J, Wong P, Luo KL, Trepman P, Wang ET, Choi H, Burge CB, Lodish HF. Muscleblind-like 1 (Mbnl1) regulates pre-mRNA alternative splicing during terminal erythropoiesis. Blood 2014; 124:598-610. [PMID: 24869935 PMCID: PMC4110662 DOI: 10.1182/blood-2013-12-542209] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/16/2014] [Indexed: 12/18/2022] Open
Abstract
The scope and roles of regulated isoform gene expression during erythroid terminal development are poorly understood. We identified hundreds of differentiation-associated isoform changes during terminal erythropoiesis. Sequences surrounding cassette exons of skipped exon events are enriched for motifs bound by the Muscleblind-like (MBNL) family of splicing factors. Knockdown of Mbnl1 in cultured murine fetal liver erythroid progenitors resulted in a strong block in erythroid differentiation and disrupted the developmentally regulated exon skipping of Ndel1 mRNA, which is bound by MBNL1 and critical for erythroid terminal proliferation. These findings reveal an unanticipated scope of the alternative splicing program and the importance of Mbnl1 during erythroid terminal differentiation.
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Affiliation(s)
- Albert W Cheng
- Whitehead Institute for Biomedical Research, Cambridge, MA; Computational and Systems Biology Program, and
| | - Jiahai Shi
- Whitehead Institute for Biomedical Research, Cambridge, MA
| | - Piu Wong
- Whitehead Institute for Biomedical Research, Cambridge, MA
| | - Katherine L Luo
- Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and
| | - Paula Trepman
- Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and
| | - Eric T Wang
- Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Heejo Choi
- Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and
| | - Christopher B Burge
- Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and
| | - Harvey F Lodish
- Whitehead Institute for Biomedical Research, Cambridge, MA; Departments of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA; and
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Xue L, Galdass M, Gnanapragasam MN, Manwani D, Bieker JJ. Extrinsic and intrinsic control by EKLF (KLF1) within a specialized erythroid niche. Development 2014; 141:2245-54. [PMID: 24866116 DOI: 10.1242/dev.103960] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The erythroblastic island provides an important nutritional and survival support niche for efficient erythropoietic differentiation. Island integrity is reliant on adhesive interactions between erythroid and macrophage cells. We show that erythroblastic islands can be formed from single progenitor cells present in differentiating embryoid bodies, and that these correspond to erythro-myeloid progenitors (EMPs) that first appear in the yolk sac of the early developing embryo. Erythroid Krüppel-like factor (EKLF; KLF1), a crucial zinc finger transcription factor, is expressed in the EMPs, and plays an extrinsic role in erythroid maturation by being expressed in the supportive macrophage of the erythroblastic island and regulating relevant genes important for island integrity within these cells. Together with its well-established intrinsic contributions to erythropoiesis, EKLF thus plays a coordinating role between two different cell types whose interaction provides the optimal environment to generate a mature red blood cell.
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Affiliation(s)
- Li Xue
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Mariann Galdass
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Merlin Nithya Gnanapragasam
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Deepa Manwani
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - James J Bieker
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
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Jacobsen RN, Forristal CE, Raggatt LJ, Nowlan B, Barbier V, Kaur S, van Rooijen N, Winkler IG, Pettit AR, Levesque JP. Mobilization with granulocyte colony-stimulating factor blocks medullar erythropoiesis by depleting F4/80+VCAM1+CD169+ER-HR3+Ly6G+ erythroid island macrophages in the mouse. Exp Hematol 2014; 42:547-61.e4. [DOI: 10.1016/j.exphem.2014.03.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/25/2014] [Accepted: 03/31/2014] [Indexed: 01/05/2023]
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Yabas M, Coupland LA, Cromer D, Winterberg M, Teoh NC, D'Rozario J, Kirk K, Bröer S, Parish CR, Enders A. Mice deficient in the putative phospholipid flippase ATP11C exhibit altered erythrocyte shape, anemia, and reduced erythrocyte life span. J Biol Chem 2014; 289:19531-7. [PMID: 24898253 DOI: 10.1074/jbc.c114.570267] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Transmembrane lipid transporters are believed to establish and maintain phospholipid asymmetry in biological membranes; however, little is known about the in vivo function of the specific transporters involved. Here, we report that developing erythrocytes from mice lacking the putative phosphatidylserine flippase ATP11C showed a lower rate of PS translocation in vitro compared with erythrocytes from wild-type littermates. Furthermore, the mutant mice had an elevated percentage of phosphatidylserine-exposing mature erythrocytes in the periphery. Although erythrocyte development in ATP11C-deficient mice was normal, the mature erythrocytes had an abnormal shape (stomatocytosis), and the life span of mature erythrocytes was shortened relative to that in control littermates, resulting in anemia in the mutant mice. Thus, our findings uncover an essential role for ATP11C in erythrocyte morphology and survival and provide a new candidate for the rare inherited blood disorder stomatocytosis with uncompensated anemia.
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Affiliation(s)
- Mehmet Yabas
- From the Ramaciotti Immunization Genomics Laboratory and
| | - Lucy A Coupland
- Cancer and Vascular Biology Group, Department of Immunology, The John Curtin School of Medical Research, and the Clinical Haematology Unit, The Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - Deborah Cromer
- the Complex Systems in Biology Group, Centre for Vascular Research, University of New South Wales, Kensington, New South Wales 2052, Australia, and
| | - Markus Winterberg
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Narci C Teoh
- the Liver Research Group, Australian National University Medical School at the Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - James D'Rozario
- the Clinical Haematology Unit, The Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - Kiaran Kirk
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Stefan Bröer
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Christopher R Parish
- Cancer and Vascular Biology Group, Department of Immunology, The John Curtin School of Medical Research, and
| | - Anselm Enders
- From the Ramaciotti Immunization Genomics Laboratory and
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Shyu YC, Lee TL, Chen X, Hsu PH, Wen SC, Liaw YW, Lu CH, Hsu PY, Lu MJ, Hwang J, Tsai MD, Hwang MJ, Chen JR, Shen CKJ. Tight regulation of a timed nuclear import wave of EKLF by PKCθ and FOE during Pro-E to Baso-E transition. Dev Cell 2014; 28:409-22. [PMID: 24576425 DOI: 10.1016/j.devcel.2014.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 11/24/2013] [Accepted: 01/13/2014] [Indexed: 11/28/2022]
Abstract
Erythropoiesis is a highly regulated process during which BFU-E are differentiated into RBCs through CFU-E, Pro-E, PolyCh-E, OrthoCh-E, and reticulocyte stages. Uniquely, most erythroid-specific genes are activated during the Pro-E to Baso-E transition. We show that a wave of nuclear import of the erythroid-specific transcription factor EKLF occurs during the Pro-E to Baso-E transition. We further demonstrate that this wave results from a series of finely tuned events, including timed activation of PKCθ, phosphorylation of EKLF at S68 by P-PKCθ(S676), and sumoylation of EKLF at K74. The latter EKLF modifications modulate its interactions with a cytoplasmic ankyrin-repeat-protein FOE and importinβ1, respectively. The role of FOE in the control of EKLF nuclear import is further supported by analysis of the subcellular distribution patterns of EKLF in FOE-knockout mice. This study reveals the regulatory mechanisms of the nuclear import of EKLF, which may also be utilized in the nuclear import of other factors.
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Affiliation(s)
- Yu-Chiau Shyu
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Beitou, Taipei 112, Taiwan, ROC; Department of Education and Research, Taipei City Hospital, Da'an, Taipei 103, Taiwan, ROC; Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC.
| | - Tung-Liang Lee
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Xin Chen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Pang-Hung Hsu
- The Genomics Research Center, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Shau-Ching Wen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Yi-Wei Liaw
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Chi-Huan Lu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Po-Yen Hsu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Mu-Jie Lu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - JauLang Hwang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Ming-Daw Tsai
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Ming-Jing Hwang
- Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Jim-Ray Chen
- Department of Pathology, Keelung Chang Gung Memorial Hospital, Anle, Keelung 204, Taiwan, ROC; College of Medicine, Chang Gung University, Kwei-Shan, Taoyuan 259, Taiwan, ROC
| | - Che-Kun James Shen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC.
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Extensively self-renewing erythroblasts derived from transgenic β-yac mice is a novel model system for studying globin switching and erythroid maturation. Exp Hematol 2014; 42:536-46.e8. [PMID: 24704162 DOI: 10.1016/j.exphem.2014.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/21/2014] [Accepted: 03/25/2014] [Indexed: 11/22/2022]
Abstract
Globin gene regulation occurs in the context of a maturing erythroid cell, which is undergoing significant changes in chromatin structure and gene expression. There are few model systems available that facilitate studies of globin gene regulation in the context of erythroid maturation. Extensively self-renewing erythroblasts (ESREs) are a nontransformed model of erythroid maturation derived from murine fetal liver or yolk sac. Imaging flow cytometry and RNA-seq studies demonstrate that ESREs functionally and molecularly model erythroid maturation. To address the need for a model system that also recapitulates human globin switching, ESREs were derived from mice transgenic for the complete human β-globin locus (β-yac ESREs). β-yac ESREs express β-globin from the transgenic human locus, with minimal γ-globin expression. When treated with hydroxyurea or inhibitors to histone deacetylases, DNA methyltransferases, or the histone demethylase lysine specific demethylase 1 (LSD1), β-Yac ESREs significantly increase their γ-globin expression, demonstrating their utility for studying agents that influence maturational globin switching. β-yac ESREs were further used to characterize the secondary effects of LSD1 inhibition on erythroid maturation, with inhibition of LSD1 resulting in altered cell and nuclear size, prolonged Kit expression, and decreased rates of enucleation consistent with impaired maturation. Taken together, these studies demonstrate that β-yac ESREs have significant utility for identifying modulators of maturational globin switching as well as for studying the broader role of those modulators in erythroid maturation.
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121
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Kong XZ, Yin RH, Ning HM, Zheng WW, Dong XM, Yang Y, Xu FF, Li JJ, Zhan YQ, Yu M, Ge CH, Zhang JH, Chen H, Li CY, Yang XM. Effects of THAP11 on erythroid differentiation and megakaryocytic differentiation of K562 cells. PLoS One 2014; 9:e91557. [PMID: 24637716 PMCID: PMC3956667 DOI: 10.1371/journal.pone.0091557] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 02/13/2014] [Indexed: 12/16/2022] Open
Abstract
Hematopoiesis is a complex process regulated by sets of transcription factors in a stage-specific and context-dependent manner. THAP11 is a transcription factor involved in cell growth, ES cell pluripotency, and embryogenesis. Here we showed that THAP11 was down-regulated during erythroid differentiation but up-regulated during megakaryocytic differentiation of cord blood CD34+ cells. Overexpression of THAP11 in K562 cells inhibited the erythroid differentiation induced by hemin with decreased numbers of benzidine-positive cells and decreased mRNA levels of α-globin (HBA) and glycophorin A (GPA), and knockdown of THAP11 enhanced the erythroid differentiation. Conversely, THAP11 overexpression accelerated the megakaryocytic differentiation induced by phorbol myristate acetate (PMA) with increased percentage of CD41+ cells, increased numbers of 4N cells, and elevated CD61 mRNA levels, and THAP11 knockdown attenuated the megakaryocytic differentiation. The expression levels of transcription factors such as c-Myc, c-Myb, GATA-2, and Fli1 were changed by THAP11 overexpression. In this way, our results suggested that THAP11 reversibly regulated erythroid and megakaryocytic differentiation.
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Affiliation(s)
- Xiang-Zhen Kong
- Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Rong-Hua Yin
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
- State Key Laboratory of Proteomics, Beijing, China
| | - Hong-Mei Ning
- Department of Hematopoietic Stem Cell Transplantation, Affiliated Hospital to Academy of Military Medical Sciences, Beijing, China
| | - Wei-Wei Zheng
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Xiao-Ming Dong
- Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
| | - Yang Yang
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Fei-Fei Xu
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Jian-Jie Li
- Department of Pulmonary Neoplasms Internal Medicine, Affiliated Hospital to Academy of Military Medicine Sciences, Beijing, China
| | - Yi-Qun Zhan
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Miao Yu
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Chang-Hui Ge
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Jian-Hong Zhang
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Hui Chen
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Chang-Yan Li
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
- State Key Laboratory of Proteomics, Beijing, China
- * E-mail: (XMY); (CYL)
| | - Xiao-Ming Yang
- Department of Pharmaceutical Engineering, Tianjin University, Tianjin, China
- Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, Beijing, China
- State Key Laboratory of Proteomics, Beijing, China
- * E-mail: (XMY); (CYL)
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Abstract
We recently developed fluorescence-activated cell sorting (FACS)-based methods to purify morphologically and functionally discrete populations of cells, each representing specific stages of terminal erythroid differentiation. We used these techniques to obtain pure populations of both human and murine erythroblasts at distinct developmental stages. RNA was prepared from these cells and subjected to RNA sequencing analyses, creating unbiased, stage-specific transcriptomes. Tight clustering of transcriptomes from differing stages, even between biologically different replicates, validated the utility of the FACS-based assays. Bioinformatic analyses revealed that there were marked differences between differentiation stages, with both shared and dissimilar gene expression profiles defining each stage within transcriptional space. There were vast temporal changes in gene expression across the differentiation stages, with each stage exhibiting unique transcriptomes. Clustering and network analyses revealed that varying stage-specific patterns of expression observed across differentiation were enriched for genes of differing function. Numerous differences were present between human and murine transcriptomes, with significant variation in the global patterns of gene expression. These data provide a significant resource for studies of normal and perturbed erythropoiesis, allowing a deeper understanding of mechanisms of erythroid development in various inherited and acquired erythroid disorders.
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123
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Transcriptional divergence and conservation of human and mouse erythropoiesis. Proc Natl Acad Sci U S A 2014; 111:4103-8. [PMID: 24591581 DOI: 10.1073/pnas.1401598111] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Mouse models have been used extensively for decades and have been instrumental in improving our understanding of mammalian erythropoiesis. Nonetheless, there are several examples of variation between human and mouse erythropoiesis. We performed a comparative global gene expression study using data from morphologically identical stage-matched sorted populations of human and mouse erythroid precursors from early to late erythroblasts. Induction and repression of major transcriptional regulators of erythropoiesis, as well as major erythroid-important proteins, are largely conserved between the species. In contrast, at a global level we identified a significant extent of divergence between the species, both at comparable stages and in the transitions between stages, especially for the 500 most highly expressed genes during development. This suggests that the response of multiple developmentally regulated genes to key erythroid transcriptional regulators represents an important modification that has occurred in the course of erythroid evolution. In developing a systematic framework to understand and study conservation and divergence between human and mouse erythropoiesis, we show how mouse models can fail to mimic specific human diseases and provide predictions for translating findings from mouse models to potential therapies for human disease.
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Abstract
Red blood cells (RBCs), which constitute the most abundant cell type in the body, come in two distinct flavors- primitive and definitive. Definitive RBCs in mammals circulate as smaller, anucleate cells during fetal and postnatal life, while primitive RBCs circulate transiently in the early embryo as large, nucleated cells before ultimately enucleating. Both cell types are formed from lineage-committed progenitors that generate a series of morphologically identifiable precursors that enucleate to form mature RBCs. While definitive erythroid precursors mature extravascularly in the fetal liver and postnatal marrow in association with macrophage cells, primitive erythroid precursors mature as a semi-synchronous cohort in the embryonic bloodstream. While the cytoskeletal network is critical for the maintenance of cell shape and the deformability of definitive RBCs, little is known about the components and function of the cytoskeleton in primitive erythroblasts. Erythropoietin (EPO) is a critical regulator of late-stage definitive, but not primitive, erythroid progenitor survival. However, recent studies indicate that EPO regulates multiple aspects of terminal maturation of primitive murine and human erythroid precursors, including cell survival, proliferation, and the rate of terminal maturation. Primitive and definitive erythropoiesis share central transcriptional regulators, including Gata1 and Klf1, but are also characterized by the differential expression and function of other regulators, including myb, Sox6, and Bcl11A. Flow cytometry-based methodologies, developed to purify murine and human stage-specific erythroid precursors, have enabled comparative global gene expression studies and are providing new insights into the biology of erythroid maturation.
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Affiliation(s)
- James Palis
- Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester Medical CenterRochester, NY, USA
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125
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Vieceli Dalla Sega F, Zambonin L, Fiorentini D, Rizzo B, Caliceti C, Landi L, Hrelia S, Prata C. Specific aquaporins facilitate Nox-produced hydrogen peroxide transport through plasma membrane in leukaemia cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:806-14. [PMID: 24440277 DOI: 10.1016/j.bbamcr.2014.01.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 12/09/2013] [Accepted: 01/10/2014] [Indexed: 12/30/2022]
Abstract
In the last decade, the generation and the role of reactive oxygen species (ROS), particularly hydrogen peroxide, in cell signalling transduction pathways have been intensively studied, and it is now clear that an increase of ROS level affects cellular growth and proliferation pathways related to cancer development. Hydrogen peroxide (H2O2) has been long thought to permeate biological membranes by simple diffusion since recent evidence challenged this notion disclosing the role of aquaporin water channels (AQP) in mediating H2O2 transport across plasma membranes. We previously demonstrated that NAD(P)H oxidase (Nox)-generated ROS sustain glucose uptake and cellular proliferation in leukaemia cells. The aim of this study was to assess whether specific AQP isoforms can channel Nox-produced H2O2 across the plasma membrane of leukaemia cells affecting downstream pathways linked to cell proliferation. In this work, we demonstrate that AQP inhibition caused a decrease in intracellular ROS accumulation in leukaemia cells both when H2O2 was produced by Nox enzymes and when it was exogenously added. Furthermore, AQP8 overexpression or silencing resulted to modulate VEGF capacity of triggering an H2O2 intracellular level increase or decrease, respectively. Finally, we report that AQP8 is capable of increasing H2O2-induced phosphorylation of both PI3K and p38 MAPK and that AQP8 expression affected positively cell proliferation. Taken together, the results here reported indicate that AQP8 is able to modulate H2O2 transport through the plasma membrane affecting redox signalling linked to leukaemia cell proliferation.
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Affiliation(s)
| | - Laura Zambonin
- Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Diana Fiorentini
- Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Benedetta Rizzo
- Department for Life Quality Studies, University of Bologna, Italy
| | - Cristiana Caliceti
- Department of Cardiology and Laboratory for Technologies of Advanced Therapies (LTTA Center), University Hospital of Ferrara and Maria Cecilia Hospital, GVM Care&Research, E.S: Health Science Foundation, Cotignola, Italy
| | | | - Silvana Hrelia
- Department for Life Quality Studies, University of Bologna, Italy
| | - Cecilia Prata
- Department of Pharmacy and Biotechnology, University of Bologna, Italy
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Gao X, Johnson KD, Chang YI, Boyer ME, Dewey CN, Zhang J, Bresnick EH. Gata2 cis-element is required for hematopoietic stem cell generation in the mammalian embryo. ACTA ACUST UNITED AC 2013; 210:2833-42. [PMID: 24297994 PMCID: PMC3865483 DOI: 10.1084/jem.20130733] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cis-element requirement for the emergence of HSCs in the AGM and for hemogenic endothelium to generate HSC-containing c-Kit+ cell clusters. The generation of hematopoietic stem cells (HSCs) from hemogenic endothelium within the aorta, gonad, mesonephros (AGM) region of the mammalian embryo is crucial for development of the adult hematopoietic system. We described a deletion of a Gata2 cis-element (+9.5) that depletes fetal liver HSCs, is lethal at E13–14 of embryogenesis, and is mutated in an immunodeficiency that progresses to myelodysplasia/leukemia. Here, we demonstrate that the +9.5 element enhances Gata2 expression and is required to generate long-term repopulating HSCs in the AGM. Deletion of the +9.5 element abrogated the capacity of hemogenic endothelium to generate HSC-containing clusters in the aorta. Genomic analyses indicated that the +9.5 element regulated a rich ensemble of genes that control hemogenic endothelium and HSCs, as well as genes not implicated in hematopoiesis. These results reveal a mechanism that controls stem cell emergence from hemogenic endothelium to establish the adult hematopoietic system.
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Affiliation(s)
- Xin Gao
- Department of Cell and Regenerative Biology, Carbone Cancer Center, and 2 McArdle Laboratory for Cancer Research, 3 UW-Madison Blood Research Program; and 4 Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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128
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Elahi S, Ertelt JM, Kinder JM, Jiang TT, Zhang X, Xin L, Chaturvedi V, Strong BS, Qualls JE, Steinbrecher KA, Kalfa TA, Shaaban AF, Way SS. Immunosuppressive CD71+ erythroid cells compromise neonatal host defence against infection. Nature 2013; 504:158-62. [PMID: 24196717 DOI: 10.1038/nature12675] [Citation(s) in RCA: 278] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/18/2013] [Indexed: 12/15/2022]
Abstract
Newborn infants are highly susceptible to infection. This defect in host defence has generally been ascribed to the immaturity of neonatal immune cells; however, the degree of hyporesponsiveness is highly variable and depends on the stimulation conditions. These discordant responses illustrate the need for a more unified explanation for why immunity is compromised in neonates. Here we show that physiologically enriched CD71(+) erythroid cells in neonatal mice and human cord blood have distinctive immunosuppressive properties. The production of innate immune protective cytokines by adult cells is diminished after transfer to neonatal mice or after co-culture with neonatal splenocytes. Neonatal CD71(+) cells express the enzyme arginase-2, and arginase activity is essential for the immunosuppressive properties of these cells because molecular inhibition of this enzyme or supplementation with L-arginine overrides immunosuppression. In addition, the ablation of CD71(+) cells in neonatal mice, or the decline in number of these cells as postnatal development progresses parallels the loss of suppression, and restored resistance to the perinatal pathogens Listeria monocytogenes and Escherichia coli. However, CD71(+) cell-mediated susceptibility to infection is counterbalanced by CD71(+) cell-mediated protection against aberrant immune cell activation in the intestine, where colonization with commensal microorganisms occurs swiftly after parturition. Conversely, circumventing such colonization by using antimicrobials or gnotobiotic germ-free mice overrides these protective benefits. Thus, CD71(+) cells quench the excessive inflammation induced by abrupt colonization with commensal microorganisms after parturition. This finding challenges the idea that the susceptibility of neonates to infection reflects immune-cell-intrinsic defects and instead highlights processes that are developmentally more essential and inadvertently mitigate innate immune protection. We anticipate that these results will spark renewed investigation into the need for immunosuppression in neonates, as well as improved strategies for augmenting host defence in this vulnerable population.
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Affiliation(s)
- Shokrollah Elahi
- Division of Infectious Diseases and Perinatal Institute, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
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Malik J, Kim AR, Tyre KA, Cherukuri AR, Palis J. Erythropoietin critically regulates the terminal maturation of murine and human primitive erythroblasts. Haematologica 2013; 98:1778-87. [PMID: 23894012 PMCID: PMC3815180 DOI: 10.3324/haematol.2013.087361] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 07/26/2013] [Indexed: 12/25/2022] Open
Abstract
Primitive erythroid cells, the first red blood cells produced in the mammalian embryo, are necessary for embryonic survival. Erythropoietin and its receptor EpoR, are absolutely required for survival of late-stage definitive erythroid progenitors in the fetal liver and adult bone marrow. Epo- and Epor-null mice die at E13.5 with a lack of definitive erythrocytes. However, the persistence of circulating primitive erythroblasts raises questions about the role of erythropoietin/EpoR in primitive erythropoiesis. Using Epor-null mice and a novel primitive erythroid 2-step culture we found that erythropoietin is not necessary for specification of primitive erythroid progenitors. However, Epor-null embryos develop a progressive, profound anemia by E12.5 as primitive erythroblasts mature as a synchronous cohort. This anemia results from reduced primitive erythroblast proliferation associated with increased p27 expression, from advanced cellular maturation, and from markedly elevated rates of apoptosis associated with an imbalance in pro- and anti-apoptotic gene expression. Both mouse and human primitive erythroblasts cultured without erythropoietin also undergo accelerated maturation and apoptosis at later stages of maturation. We conclude that erythropoietin plays an evolutionarily conserved role in promoting the proliferation, survival, and appropriate timing of terminal maturation of primitive erythroid precursors.
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130
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Fraser ST. The modern primitives: applying new technological approaches to explore the biology of the earliest red blood cells. ISRN HEMATOLOGY 2013; 2013:568928. [PMID: 24222861 PMCID: PMC3814094 DOI: 10.1155/2013/568928] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 08/25/2013] [Indexed: 01/01/2023]
Abstract
One of the most critical stages in mammalian embryogenesis is the independent production of the embryo's own circulating, functional red blood cells. Correspondingly, erythrocytes are the first cell type to become functionally mature during embryogenesis. Failure to achieve this invariably leads to in utero lethality. The recent application of technologies such as transcriptome analysis, flow cytometry, mutant embryo analysis, and transgenic fluorescent gene expression reporter systems has shed new light on the distinct erythroid lineages that arise early in development. Here, I will describe the similarities and differences between the distinct erythroid populations that must form for the embryo to survive. While much of the focus of this review will be the poorly understood primitive erythroid lineage, a discussion of other erythroid and hematopoietic lineages, as well as the cell types making up the different niches that give rise to these lineages, is essential for presenting an appropriate developmental context of these cells.
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Affiliation(s)
- Stuart T. Fraser
- Disciplines of Physiology, Anatomy and Histology, Bosch Institute, School of Medical Sciences, University of Sydney, Medical Foundation Building K25, 92-94 Parramatta Road, Camperdown, NSW 2050, Australia
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131
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Establishing a hematopoietic genetic network through locus-specific integration of chromatin regulators. Proc Natl Acad Sci U S A 2013; 110:E3398-407. [PMID: 23959865 DOI: 10.1073/pnas.1302771110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The establishment and maintenance of cell type-specific transcriptional programs require an ensemble of broadly expressed chromatin remodeling and modifying enzymes. Many questions remain unanswered regarding the contributions of these enzymes to specialized genetic networks that control critical processes, such as lineage commitment and cellular differentiation. We have been addressing this problem in the context of erythrocyte development driven by the transcription factor GATA-1 and its coregulator Friend of GATA-1 (FOG-1). As certain GATA-1 target genes have little to no FOG-1 requirement for expression, presumably additional coregulators can mediate GATA-1 function. Using a genetic complementation assay and RNA interference in GATA-1-null cells, we demonstrate a vital link between GATA-1 and the histone H4 lysine 20 methyltransferase PR-Set7/SetD8 (SetD8). GATA-1 selectively induced H4 monomethylated lysine 20 at repressed, but not activated, loci, and endogenous SetD8 mediated GATA-1-dependent repression of a cohort of its target genes. GATA-1 used different combinations of SetD8, FOG-1, and the FOG-1-interacting nucleosome remodeling and deacetylase complex component Mi2β to repress distinct target genes. Implicating SetD8 as a context-dependent GATA-1 corepressor expands the repertoire of coregulators mediating establishment/maintenance of the erythroid cell genetic network, and provides a biological framework for dissecting the cell type-specific functions of this important coregulator. We propose a coregulator matrix model in which distinct combinations of chromatin regulators are required at different GATA-1 target genes, and the unique attributes of the target loci mandate these combinations.
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Satchwell TJ, Pellegrin S, Bianchi P, Hawley BR, Gampel A, Mordue KE, Budnik A, Fermo E, Barcellini W, Stephens DJ, van den Akker E, Toye AM. Characteristic phenotypes associated with congenital dyserythropoietic anemia (type II) manifest at different stages of erythropoiesis. Haematologica 2013; 98:1788-96. [PMID: 23935019 DOI: 10.3324/haematol.2013.085522] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Congenital dyserythropoietic anemia type II is an autosomally recessive form of hereditary anemia caused by SEC23B gene mutations. Patients exhibit characteristic phenotypes including multinucleate erythroblasts, erythrocytes with hypoglycosylated membrane proteins and an apparent double plasma membrane. Despite ubiquitous expression of SEC23B, the effects of mutations in this gene are confined to the erythroid lineage and the basis of this erythroid specificity remains to be defined. In addition, little is known regarding the stage at which the disparate phenotypes of this disease manifest during erythropoiesis. We employ an in vitro culture system to monitor the appearance of the defining phenotypes associated with congenital dyserythropoietic anemia type II during terminal differentiation of erythroblasts derived from small volumes of patient peripheral blood. Membrane protein hypoglycosylation was detected by the basophilic stage, preceding the onset of multinuclearity in orthochromatic erythroblasts that occurs coincident with the loss of secretory pathway proteins including SEC23A during erythropoiesis. Endoplasmic reticulum remnants were observed in nascent reticulocytes of both diseased and healthy donor cultures but were lost upon further maturation of normal reticulocytes, implicating a defect of ER clearance during reticulocyte maturation in congenital dyserythropoietic anemia type II. We also demonstrate distinct isoform and species-specific expression profiles of SEC23 during terminal erythroid differentiation and identify a prolonged expression of SEC23A in murine erythropoiesis compared to humans. We propose that SEC23A is able to compensate for the absence of SEC23B in mouse erythroblasts, providing a basis for the absence of phenotype within the erythroid lineage of a recently described SEC23B knockout mouse.
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133
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Baron MH, Vacaru A, Nieves J. Erythroid development in the mammalian embryo. Blood Cells Mol Dis 2013; 51:213-9. [PMID: 23932234 DOI: 10.1016/j.bcmd.2013.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/25/2013] [Indexed: 12/22/2022]
Abstract
Erythropoiesis is the process by which progenitors for red blood cells are produced and terminally differentiate. In all vertebrates, two morphologically distinct erythroid lineages (primitive, embryonic, and definitive, fetal/adult) form successively within the yolk sac, fetal liver, and marrow and are essential for normal development. Red blood cells have evolved highly specialized functions in oxygen transport, defense against oxidation, and vascular remodeling. Here we review key features of the ontogeny of red blood cell development in mammals, highlight similarities and differences revealed by genetic and gene expression profiling studies, and discuss methods for identifying erythroid cells at different stages of development and differentiation.
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Affiliation(s)
- Margaret H Baron
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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134
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Greenfest-Allen E, Malik J, Palis J, Stoeckert CJ. Stat and interferon genes identified by network analysis differentially regulate primitive and definitive erythropoiesis. BMC SYSTEMS BIOLOGY 2013; 7:38. [PMID: 23675896 PMCID: PMC3668222 DOI: 10.1186/1752-0509-7-38] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/30/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Hematopoietic ontogeny is characterized by overlapping waves of primitive, fetal definitive, and adult definitive erythroid lineages. Our aim is to identify differences in the transcriptional control of these distinct erythroid cell maturation pathways by inferring and analyzing gene-interaction networks from lineage-specific expression datasets. Inferred networks are strongly connected and do not fit a scale-free model, making it difficult to identify essential regulators using the hub-essentiality standard. RESULTS We employed a semi-supervised machine learning approach to integrate measures of network topology with expression data to score gene essentiality. The algorithm was trained and tested on the adult and fetal definitive erythroid lineages. When applied to the primitive erythroid lineage, 144 high scoring transcription factors were found to be differentially expressed between the primitive and adult definitive erythroid lineages, including all expressed STAT-family members. Differential responses of primitive and definitive erythroblasts to a Stat3 inhibitor and IFNγ in vitro supported the results of the computational analysis. Further investigation of the original expression data revealed a striking signature of Stat1-related genes in the adult definitive erythroid network. Among the potential pathways known to utilize Stat1, interferon (IFN) signaling-related genes were expressed almost exclusively within the adult definitive erythroid network. CONCLUSIONS In vitro results support the computational prediction that differential regulation and downstream effectors of STAT signaling are key factors that distinguish the transcriptional control of primitive and definitive erythroid cell maturation.
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Affiliation(s)
- Emily Greenfest-Allen
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey Malik
- Center for Pediatric Biomedical Research, Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - James Palis
- Center for Pediatric Biomedical Research, Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Christian J Stoeckert
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Pope NJ, Bresnick EH. Establishment of a cell-type-specific genetic network by the mediator complex component Med1. Mol Cell Biol 2013; 33:1938-55. [PMID: 23459945 PMCID: PMC3647965 DOI: 10.1128/mcb.00141-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 02/23/2013] [Indexed: 01/11/2023] Open
Abstract
The intense physiologic demand to generate vast numbers of red blood cells requires the establishment of a complex genetic network by the master regulatory transcription factor GATA-1 and its coregulators. This network dictates the genesis of enucleated erythrocytes by orchestrating the survival, proliferation, and differentiation of progenitor cells. In addition to the crucial GATA-1 coregulator Friend of GATA-1 (FOG-1), a component of the Mediator complex, Med1, facilitates GATA-1-dependent transcription at select target genes and controls erythropoiesis. It is not known to what extent Med1 contributes to GATA-1 function or whether Med1 controls a large or restricted cohort of genes that are not regulated by GATA-1. Using a genetic complementation assay in GATA-1-null erythroid cells, we demonstrate that Med1 and another Mediator component, Med25, regulate a restricted cohort of genes that are predominantly not controlled by GATA-1. Most of these genes were not regulated by Med1 in fibroblasts. Loss-of-function analyses with GATA-1-independent Med1 target genes indicate that Rrad, which encodes a small GTPase induced during human erythropoiesis, conferred erythroid cell survival. Thus, while Med1 is a context-dependent GATA-1 coregulator, it also exerts specialized functions in erythroid cells to control GATA-1-independent, cell-type-specific genes, which include candidate regulators of erythroid cell development and function.
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Affiliation(s)
- Nathaniel J Pope
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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