1
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Yokomizo T. Hematopoietic cluster formation: an essential prelude to blood cell genesis. Exp Hematol 2024; 136:104284. [PMID: 39032856 DOI: 10.1016/j.exphem.2024.104284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 07/10/2024] [Accepted: 07/15/2024] [Indexed: 07/23/2024]
Abstract
Adult blood cells are produced in the bone marrow by hematopoietic stem cells (HSCs), the origin of which can be traced back to fetal developmental stages. Indeed, during mouse development, at days 10-11 of gestation, the aorta-gonad-mesonephros (AGM) region is a primary site of HSC production, with characteristic cell clusters related to stem cell genesis observed in the dorsal aorta. Similar clusters linked with hematopoiesis are also observed in the other sites such as the yolk sac and placenta. In this review, I outline the formation and function of these clusters, focusing on the well-characterized intra-aortic hematopoietic clusters (IAHCs).
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Affiliation(s)
- Tomomasa Yokomizo
- Microscopic and Developmental Anatomy, Tokyo Women's Medical University, Tokyo, Japan.
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2
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Weijts B, Robin C. Capturing embryonic hematopoiesis in temporal and spatial dimensions. Exp Hematol 2024; 136:104257. [PMID: 38897373 DOI: 10.1016/j.exphem.2024.104257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/03/2024] [Accepted: 06/10/2024] [Indexed: 06/21/2024]
Abstract
Hematopoietic stem cells (HSCs) possess the ability to sustain the continuous production of all blood cell types throughout an organism's lifespan. Although primarily located in the bone marrow of adults, HSCs originate during embryonic development. Visualization of the birth of HSCs, their developmental trajectory, and the specific interactions with their successive niches have significantly contributed to our understanding of the biology and mechanics governing HSC formation and expansion. Intravital techniques applied to live embryos or non-fixed samples have remarkably provided invaluable insights into the cellular and anatomical origins of HSCs. These imaging technologies have also shed light on the dynamic interactions between HSCs and neighboring cell types within the surrounding microenvironment or niche, such as endothelial cells or macrophages. This review delves into the advancements made in understanding the origin, production, and cellular interactions of HSCs, particularly during the embryonic development of mice and zebrafish, focusing on studies employing (live) imaging analysis.
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Affiliation(s)
- Bart Weijts
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Catherine Robin
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands; Regenerative Medicine Center, University Medical Center Utrecht, Utrecht, The Netherlands.
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3
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Weijts B, Yvernogeau L, Robin C. Recent Advances in Developmental Hematopoiesis: Diving Deeper With New Technologies. Front Immunol 2021; 12:790379. [PMID: 34899758 PMCID: PMC8652083 DOI: 10.3389/fimmu.2021.790379] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 10/28/2021] [Indexed: 12/15/2022] Open
Abstract
The journey of a hematopoietic stem cell (HSC) involves the passage through successive anatomical sites where HSCs are in direct contact with their surrounding microenvironment, also known as niche. These spatial and temporal cellular interactions throughout development are required for the acquisition of stem cell properties, and for maintaining the HSC pool through balancing self-renewal, quiescence and lineage commitment. Understanding the context and consequences of these interactions will be imperative for our understanding of HSC biology and will lead to the improvement of in vitro production of HSCs for clinical purposes. The aorta-gonad-mesonephros (AGM) region is in this light of particular interest since this is the cradle of HSC emergence during the embryonic development of all vertebrate species. In this review, we will focus on the developmental origin of HSCs and will discuss the novel technological approaches and recent progress made to identify the cellular composition of the HSC supportive niche and the underlying molecular events occurring in the AGM region.
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Affiliation(s)
- Bart Weijts
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences) & University Medical Center Utrecht, Utrecht, Netherlands
| | - Laurent Yvernogeau
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences) & University Medical Center Utrecht, Utrecht, Netherlands
| | - Catherine Robin
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences) & University Medical Center Utrecht, Utrecht, Netherlands
- Regenerative Medicine Center, University Medical Center Utrecht, Utrecht, Netherlands
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4
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He W, Zhang Y, Cao Z, Ye Z, Lu X, Fan J, Peng W, Li Z. Wild-Type p53-Induced Phosphatase 1 Plays a Positive Role in Hematopoiesis in the Mouse Embryonic Head. Front Cell Dev Biol 2021; 9:732527. [PMID: 34604235 PMCID: PMC8484912 DOI: 10.3389/fcell.2021.732527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/18/2021] [Indexed: 12/02/2022] Open
Abstract
The first adult repopulating hematopoietic stem cells (HSCs) are found in the aorta-gonad-mesonephros (AGM) region, which are produced from hemogenic endothelial cells. Embryonic head is the other site for HSC development. Wild-type p53-induced phosphatase 1 (Wip1) is a type-2Cδ family serine/threonine phosphatase involved in various cellular processes such as lymphoid development and differentiation of adult HSCs. Most recently, we have shown that Wip1 modulates the pre-HSC maturation in the AGM region. However, it is not clear whether Wip1 regulates hematopoiesis in the embryonic head. Here we reported that disruption of Wip1 resulted in a decrease of hematopoietic progenitor cell number in the embryonic head. In vivo transplantation assays showed a reduction of HSC function after Wip1 ablation. We established that Wip1 deletion reduced the frequency and cell number of microglia in the embryonic head. Further observations revealed that Wip1 absence enhanced the gene expression of microglia-derived pro-inflammatory factors. Thus, it is likely that Wip1 functions as a positive regulator in HSC development by regulating the function of microglia in the embryonic head.
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Affiliation(s)
- Wenyan He
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ying Zhang
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhan Cao
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zehua Ye
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xun Lu
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Junwan Fan
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei Peng
- Department of Stomatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhuan Li
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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5
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A role for macrophages in hematopoiesis in the embryonic head. Blood 2019; 134:1929-1940. [PMID: 31697805 DOI: 10.1182/blood.2018881243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 09/21/2019] [Indexed: 12/11/2022] Open
Abstract
Along with the aorta-gonad-mesonephros region, the head is a site of hematopoietic stem and progenitor cell (HS/PC) development in the mouse embryo. Macrophages are present in both these embryonic hemogenic sites, and recent studies indicate a functional interaction of macrophages with hematopoietic cells as they are generated in the aorta. Whereas brain macrophages or "microglia" are known to affect neuronal patterning and vascular circuitry in the embryonic brain, it is unknown whether macrophages play a role in head hematopoiesis. Here, we characterize head macrophages and examine whether they affect the HS/PC output of the hindbrain-branchial arch (HBA) region of the mouse embryo. We show that HBA macrophages are CD45+F4/80+CD11b+Gr1- and express the macrophage-specific Csf1r-GFP reporter. In the HBA of chemokine receptor-deficient (Cx3cr1-/-) embryos, a reduction in erythropoiesis is concomitant with a decrease in HBA macrophage percentages. In cocultures, we show that head macrophages boost hematopoietic progenitor cell numbers from HBA endothelial cells > twofold, and that the proinflammatory factor tumor necrosis factor-α is produced by head macrophages and influences HBA hematopoiesis in vitro. Taken together, head macrophages play a positive role in HBA erythropoiesis and HS/PC expansion and/or maturation, acting as microenvironmental cellular regulators in hematopoietic development.
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6
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Zhang Y, Clay D, Mitjavila-Garcia MT, Alama A, Mennesson B, Berseneff H, Louache F, Bennaceur-Griscelli A, Oberlin E. VE-Cadherin and ACE Co-Expression Marks Highly Proliferative Hematopoietic Stem Cells in Human Embryonic Liver. Stem Cells Dev 2019; 28:165-185. [PMID: 30426841 DOI: 10.1089/scd.2018.0154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Despite advances to engineer transplantable hematopoietic stem and progenitor cells (HSPCs) for research and therapy, an in-depth characterization of the developing human hematopoietic system is still lacking. The human embryonic liver is at the crossroad of several hematopoietic sites and harbors a complex hematopoietic hierarchy, including the first actively dividing HSPCs that will further seed the definitive hematopoietic organs. However, few are known about the phenotypic and functional HSPC organization operating at these stages of development. In this study, using a combination of four endothelial and hematopoietic surface markers, that is, the endothelial-specific marker vascular endothelial-cadherin (Cdh5, CD144), the pan-leukocyte antigen CD45, the hemato-endothelial marker CD34, and the angiotensin-converting enzyme (ACE, CD143), we identified distinct HSPC subsets, and among them, a population co-expressing the four markers that uniquely harbored an outstanding proliferation potential both ex vivo and in vivo. Moreover, we traced back this population to the yolk sac (YS) and aorta-gonad-mesonephros (AGM) sites of hematopoietic emergence. Taken together, our data will help to identify human HSPC self-renewal and amplification mechanisms for future cell therapies.
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Affiliation(s)
- Yanyan Zhang
- 1 Inserm, UMR 1170, Villejuif, France.,2 Paris-Saclay University, Villejuif, France.,3 Gustave Roussy, Villejuif, France
| | - Denis Clay
- 4 Inserm UMS 33, Villejuif, France.,5 André Lwoff Institute (IFR89), Villejuif, France.,6 Paris-Saclay University, Villejuif, France
| | - Maria Teresa Mitjavila-Garcia
- 5 André Lwoff Institute (IFR89), Villejuif, France.,6 Paris-Saclay University, Villejuif, France.,7 Inserm UMR 935, Villejuif, France
| | - Aurélie Alama
- 5 André Lwoff Institute (IFR89), Villejuif, France.,6 Paris-Saclay University, Villejuif, France.,7 Inserm UMR 935, Villejuif, France
| | - Benoit Mennesson
- 8 Obstetrics and Gynecology Department, René-Dubos Hospital, Pontoise, France
| | - Helene Berseneff
- 8 Obstetrics and Gynecology Department, René-Dubos Hospital, Pontoise, France
| | - Fawzia Louache
- 1 Inserm, UMR 1170, Villejuif, France.,2 Paris-Saclay University, Villejuif, France.,3 Gustave Roussy, Villejuif, France
| | - Annelise Bennaceur-Griscelli
- 5 André Lwoff Institute (IFR89), Villejuif, France.,6 Paris-Saclay University, Villejuif, France.,7 Inserm UMR 935, Villejuif, France
| | - Estelle Oberlin
- 5 André Lwoff Institute (IFR89), Villejuif, France.,6 Paris-Saclay University, Villejuif, France.,7 Inserm UMR 935, Villejuif, France
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7
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Abstract
Not all hematopoietic stem cells (HSCs) are alike. They differ in their physical characteristics such as cell cycle status and cell surface marker phenotype, they respond to different extrinsic signals, and they have different lineage outputs following transplantation. The growing body of evidence that supports heterogeneity within HSCs, which constitute the most robust cell fraction at the foundation of the adult hematopoietic system, is currently of great interest and raises questions as to why HSC subtypes exist, how they are generated and whether HSC heterogeneity affects leukemogenesis or treatment options. This Review provides a developmental overview of HSC subtypes during embryonic, fetal and adult stages of hematopoiesis and discusses the possible origins and consequences of HSC heterogeneity. Summary: This Review takes a close look at hematopoietic stem cell heterogeneity during development and in the adult, and discusses several different ways in which this heterogeneity may arise.
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Affiliation(s)
- Mihaela Crisan
- University of Edinburgh, BHF Centre for Cardiovascular Science, Scottish Centre for Regenerative Medicine, Edinburgh EH16 4UU, UK
| | - Elaine Dzierzak
- University of Edinburgh, Centre for Inflammation Research, Queens Medical Research Institute, Edinburgh EH16 4TJ, UK
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8
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Runx transcription factors in the development and function of the definitive hematopoietic system. Blood 2017; 129:2061-2069. [PMID: 28179276 DOI: 10.1182/blood-2016-12-689109] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/29/2017] [Indexed: 01/01/2023] Open
Abstract
The Runx family of transcription factors (Runx1, Runx2, and Runx3) are highly conserved and encode proteins involved in a variety of cell lineages, including blood and blood-related cell lineages, during developmental and adult stages of life. They perform activation and repressive functions in the regulation of gene expression. The requirement for Runx1 in the normal hematopoietic development and its dysregulation through chromosomal translocations and loss-of-function mutations as found in acute myeloid leukemias highlight the importance of this transcription factor in the healthy blood system. Whereas another review will focus on the role of Runx factors in leukemias, this review will provide an overview of the normal regulation and function of Runx factors in hematopoiesis and focus particularly on the biological effects of Runx1 in the generation of hematopoietic stem cells. We will present the current knowledge of the structure and regulatory features directing lineage-specific expression of Runx genes, the models of embryonic and adult hematopoietic development that provide information on their function, and some of the mechanisms by which they affect hematopoietic function.
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Yzaguirre AD, de Bruijn MFTR, Speck NA. The Role of Runx1 in Embryonic Blood Cell Formation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:47-64. [DOI: 10.1007/978-981-10-3233-2_4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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10
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Clapes T, Lefkopoulos S, Trompouki E. Stress and Non-Stress Roles of Inflammatory Signals during HSC Emergence and Maintenance. Front Immunol 2016; 7:487. [PMID: 27872627 PMCID: PMC5098161 DOI: 10.3389/fimmu.2016.00487] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 10/21/2016] [Indexed: 12/22/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are a rare population that gives rise to almost all cells of the hematopoietic system, including immune cells. Until recently, it was thought that immune cells sense inflammatory signaling and HSCs respond only secondarily to these signals. However, it was later shown that adult HSCs could directly sense and respond to inflammatory signals, resulting in a higher output of immune cells. Recent studies demonstrated that inflammatory signaling is also vital for HSC ontogeny. These signals are thought to arise in the absence of pathogens, are active during development, and indispensable for HSC formation. In contrast, during times of stress and disease, inflammatory responses can be activated and can have devastating effects on HSCs. In this review, we summarize the current knowledge about inflammatory signaling in HSC development and maintenance, as well as the endogenous molecular cues that can trigger inflammatory pathway activation. Finally, we comment of the role of inflammatory signaling in hematopoietic diseases.
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Affiliation(s)
- Thomas Clapes
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics , Freiburg , Germany
| | - Stylianos Lefkopoulos
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics , Freiburg , Germany
| | - Eirini Trompouki
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics , Freiburg , Germany
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11
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Ciau-Uitz A, Patient R. The embryonic origins and genetic programming of emerging haematopoietic stem cells. FEBS Lett 2016; 590:4002-4015. [PMID: 27531714 DOI: 10.1002/1873-3468.12363] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/26/2016] [Accepted: 08/12/2016] [Indexed: 11/10/2022]
Abstract
Haematopoietic stem cells (HSCs) emerge from the haemogenic endothelium (HE) localised in the ventral wall of the embryonic dorsal aorta (DA). The HE generates HSCs through a process known as the endothelial to haematopoietic transition (EHT), which has been visualised in live embryos and is currently under intense study. However, EHT is the culmination of multiple programming events, which are as yet poorly understood, that take place before the specification of HE. A number of haematopoietic precursor cells have been described before the emergence of definitive HSCs, but only one haematovascular progenitor, the definitive haemangioblast (DH), gives rise to the DA, HE and HSCs. DHs emerge in the lateral plate mesoderm (LPM) and have a distinct origin and genetic programme compared to other, previously described haematovascular progenitors. Although DHs have so far only been established in Xenopus embryos, evidence for their existence in the LPM of mouse and chicken embryos is discussed here. We also review the current knowledge of the origins, lineage relationships, genetic programming and differentiation of the DHs that leads to the generation of HSCs. Importantly, we discuss the significance of the gene regulatory network (GRN) that controls the programming of DHs, a better understanding of which may aid in the establishment of protocols for the de novo generation of HSCs in vitro.
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Affiliation(s)
- Aldo Ciau-Uitz
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, UK
| | - Roger Patient
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, UK
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12
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Kauts ML, Vink CS, Dzierzak E. Hematopoietic (stem) cell development - how divergent are the roads taken? FEBS Lett 2016; 590:3975-3986. [PMID: 27543859 PMCID: PMC5125883 DOI: 10.1002/1873-3468.12372] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/11/2016] [Accepted: 08/15/2016] [Indexed: 12/29/2022]
Abstract
The development of the hematopoietic system during early embryonic stages occurs in spatially and temporally distinct waves. Hematopoietic stem cells (HSC), the most potent and self‐renewing cells of this system, are produced in the final ‘definitive’ wave of hematopoietic cell generation. In contrast to HSCs in the adult, which differentiate via intermediate progenitor populations to produce functional blood cells, the generation of hematopoietic cells in the embryo prior to HSC generation occurs in the early waves by producing blood cells without intermediate progenitors (such as the ‘primitive’ hematopoietic cells). The lineage relationship between the early hematopoietic cells and the cells giving rise to HSCs, the genetic networks controlling their emergence, and the precise temporal determination of HSC fate remain topics of intense research and debate. This Review article discusses the current knowledge on the step‐wise embryonic establishment of the adult hematopoietic system, examines the roles of pivotal intrinsic regulators in this process, and raises questions concerning the temporal onset of HSC fate determination.
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Affiliation(s)
- Mari-Liis Kauts
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, UK.,Department of Cell Biology, Erasmus MC Stem Cell Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Chris S Vink
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, UK.,Department of Cell Biology, Erasmus MC Stem Cell Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Elaine Dzierzak
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, UK.,Department of Cell Biology, Erasmus MC Stem Cell Institute, Erasmus Medical Center, Rotterdam, The Netherlands
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13
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Yzaguirre AD, Speck NA. Insights into blood cell formation from hemogenic endothelium in lesser-known anatomic sites. Dev Dyn 2016; 245:1011-28. [PMID: 27389484 DOI: 10.1002/dvdy.24430] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/24/2016] [Accepted: 07/04/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Hematopoietic stem and progenitor cells (HSPCs) are generated de novo in the embryo in a process termed the endothelial to hematopoietic transition (EHT). EHT is most extensively studied in the yolk sac and dorsal aorta. Recently new sites of hematopoiesis have been described, including the heart, somites, head, and venous plexus of the yolk sac. RESULTS We examined sites of HSPC formation in well-studied and in less well-known sites by mapping the expression of the key EHT factor Runx1 along with several other markers by means of confocal microscopy. We identified sites of HSPC formation in the head, heart and somites. We also identified sites of HSPC formation in both the arterial and venous plexuses of the yolk sac, and show that progenitors with lymphoid potential are enriched in hematopoietic clusters in close proximity to arteries. Furthermore, we demonstrate that many of the cells in hematopoietic clusters resemble monocytes or granulocytes based on nuclear shape. CONCLUSIONS We identified sites of HSPC formation in the head, heart, and somites, confirming that embryonic hematopoiesis is less spatially restricted than previously thought. Furthermore, we show that HSPCs in the yolk sac with lymphoid potential are located in closer proximity to arteries than to veins. Developmental Dynamics 245:1011-1028, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Amanda D Yzaguirre
- Abramson Family Cancer Research Institute, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nancy A Speck
- Abramson Family Cancer Research Institute, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
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14
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Li Z, Vink CS, Mariani SA, Dzierzak E. Subregional localization and characterization of Ly6aGFP-expressing hematopoietic cells in the mouse embryonic head. Dev Biol 2016; 416:34-41. [PMID: 27235813 PMCID: PMC4968554 DOI: 10.1016/j.ydbio.2016.05.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 05/07/2016] [Accepted: 05/24/2016] [Indexed: 11/03/2022]
Abstract
Hematopoietic cell generation in the midgestation mouse embryo occurs through the natural transdifferentiation of temporally and spatially restricted set of hemogenic endothelial cells. These cells take on hematopoietic fate in the aorta, vitelline and umbilical arteries and appear as hematopoietic cell clusters that emerge from the vascular wall. Genetic and live imaging data have supported this. Recently, the embryonic head has been shown to contain fully functional hematopoietic stem cells (HSC). By lineage tracing, cerebrovascular specific endothelial cells were shown to contribute to the postnatal mouse hematopoietic system. Since Ly6aGFP is a marker of all HSCs, some hematopoietic cluster cells and hemogenic endothelial cells in the midgestation mouse aorta, we examine here whether embryonic head HSCs and vascular endothelial cells are positive for this marker. Whereas some head vasculature, single hematopoietic cells and all HSCs are Ly6aGFP expressing, we do not find clusters of hematopoietic cells emerging from the cerebrovasculature that are characteristic of endothelial-to-hematopoietic transition.
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Affiliation(s)
- Zhuan Li
- University of Edinburgh, Centre for Inflammation Research, Queens Medical Research Institute, Edinburgh, UK
| | - Chris S Vink
- University of Edinburgh, Centre for Inflammation Research, Queens Medical Research Institute, Edinburgh, UK
| | - Samanta A Mariani
- University of Edinburgh, Centre for Inflammation Research, Queens Medical Research Institute, Edinburgh, UK
| | - Elaine Dzierzak
- University of Edinburgh, Centre for Inflammation Research, Queens Medical Research Institute, Edinburgh, UK; Erasmus MC Stem Cell Institute, Departments of Cell Biology and Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
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