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Shi X, Zirbes KM, Rasmussen TL, Ferdous A, Garry MG, Koyano-Nakagawa N, Garry DJ. The transcription factor Mesp1 interacts with cAMP-responsive element binding protein 1 (Creb1) and coactivates Ets variant 2 (Etv2) gene expression. J Biol Chem 2015; 290:9614-25. [PMID: 25694434 DOI: 10.1074/jbc.m114.614628] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Indexed: 12/31/2022] Open
Abstract
Mesoderm posterior 1 (Mesp1) is well recognized for its role in cardiac development, although it is expressed broadly in mesodermal lineages. We have previously demonstrated important roles for Mesp1 and Ets variant 2 (Etv2) during lineage specification, but their relationship has not been defined. This study reveals that Mesp1 binds to the proximal promoter and transactivates Etv2 gene expression via the CRE motif. We also demonstrate the protein-protein interaction between Mesp1 and cAMP-responsive element binding protein 1 (Creb1) in vitro and in vivo. Utilizing transgenesis, lineage tracing, flow cytometry, and immunostaining technologies, we define the lineage relationship between Mesp1- and Etv2-expressing cell populations. We observe that the majority of Etv2-EYFP(+) cells are derived from Mesp1-Cre(+) cells in both the embryo and yolk sac. Furthermore, we observe that the conditional deletion of Etv2, using a Mesp1-Cre transgenic strategy, results in vascular and hematopoietic defects similar to those observed in the global deletion of Etv2 and that it has embryonic lethality by embryonic day 9.5. In summary, our study supports the hypothesis that Mesp1 is a direct upstream transactivator of Etv2 during embryogenesis and that Creb1 is an important cofactor of Mesp1 in the transcriptional regulation of Etv2 gene expression.
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Affiliation(s)
- Xiaozhong Shi
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Katie M Zirbes
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Tara L Rasmussen
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Anwarul Ferdous
- the Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Mary G Garry
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Naoko Koyano-Nakagawa
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Daniel J Garry
- From the Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota 55455 and
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102
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Israely E, Ginsberg M, Nolan D, Ding BS, James D, Elemento O, Rafii S, Rabbany SY. Akt suppression of TGFβ signaling contributes to the maintenance of vascular identity in embryonic stem cell-derived endothelial cells. Stem Cells 2014; 32:177-90. [PMID: 23963623 DOI: 10.1002/stem.1521] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 01/04/2023]
Abstract
The ability to generate and maintain stable in vitro cultures of mouse endothelial cells (ECs) has great potential for genetic dissection of the numerous pathologies involving vascular dysfunction as well as therapeutic applications. However, previous efforts at achieving sustained cultures of primary stable murine vascular cells have fallen short, and the cellular requirements for EC maintenance in vitro remain undefined. In this study, we have generated vascular ECs from mouse embryonic stem (ES) cells and show that active Akt is essential to their survival and propagation as homogeneous monolayers in vitro. These cells harbor the phenotypical, biochemical, and functional characteristics of ECs and expand throughout long-term cultures, while maintaining their angiogenic capacity. Moreover, Akt-transduced embryonic ECs form functional perfused vessels in vivo that anastomose with host blood vessels. We provide evidence for a novel function of Akt in stabilizing EC identity, whereby the activated form of the protein protects mouse ES cell-derived ECs from TGFβ-mediated transdifferentiation by downregulating SMAD3. These findings identify a role for Akt in regulating the developmental potential of ES cell-derived ECs and demonstrate that active Akt maintains endothelial identity in embryonic ECs by interfering with active TGFβ-mediated processes that would ordinarily usher these cells to alternate fates.
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Affiliation(s)
- Edo Israely
- Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
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103
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Di Vito A, Mignogna C, Donato G. The mysterious pathways of cardiac myxomas: a review of histogenesis, pathogenesis and pathology. Histopathology 2014; 66:321-32. [DOI: 10.1111/his.12531] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Di Vito
- Department of Clinical and Experimental Medicine; University of Catanzaro ‘Magna Graecia Medical School; Catanzaro Italy
| | - Chiara Mignogna
- Department of Health Science, Pathology Unit; University of Catanzaro ‘Magna Graecia Medical School; Catanzaro Italy
| | - Giuseppe Donato
- Department of Health Science, Pathology Unit; University of Catanzaro ‘Magna Graecia Medical School; Catanzaro Italy
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104
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OVOL2 is a critical regulator of ER71/ETV2 in generating FLK1+, hematopoietic, and endothelial cells from embryonic stem cells. Blood 2014; 124:2948-52. [PMID: 25267199 DOI: 10.1182/blood-2014-03-556332] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In this study, we report that OVOL2, a C2H2 zinc finger protein, is a novel binding protein of ER71, which is a critical transcription factor for blood and vessel development. OVOL2 directly interacted with ER71, but not with ETS1 or ETS2, in the nucleus. ER71-mediated activation of the Flk1 promoter was further enhanced by OVOL2, although OVOL2 alone failed to activate it. Consistently, coexpression of ER71 and OVOL2 in differentiating embryonic stem cells led to a significant augmentation of FLK1(+), endothelial, and hematopoietic cells. Such cooperative effects were impaired by the short hairpin RNA-mediated inhibition of Ovol2. Collectively, we show that ER71 directly interacts with OVOL2 and that such interaction is critical for FLK1(+) cell generation and their differentiation into downstream cell lineages.
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105
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Affiliation(s)
- Nicolas Ricard
- From the Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Michael Simons
- From the Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT.
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106
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Meilhac SM, Lescroart F, Blanpain C, Buckingham ME. Cardiac cell lineages that form the heart. Cold Spring Harb Perspect Med 2014; 4:a013888. [PMID: 25183852 DOI: 10.1101/cshperspect.a013888] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Myocardial cells ensure the contractility of the heart, which also depends on other mesodermal cell types for its function. Embryological experiments had identified the sources of cardiac precursor cells. With the advent of genetic engineering, novel tools have been used to reconstruct the lineage tree of cardiac cells that contribute to different parts of the heart, map the development of cardiac regions, and characterize their genetic signature. Such knowledge is of fundamental importance for our understanding of cardiogenesis and also for the diagnosis and treatment of heart malformations.
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Affiliation(s)
- Sigolène M Meilhac
- Institut Pasteur, Department of Developmental and Stem Cell Biology, CNRS URA2578, 75015 Paris, France
| | | | - Cédric Blanpain
- Université Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium WELBIO, Université Libre de Bruxelles, Brussels B-1070, Belgium
| | - Margaret E Buckingham
- Institut Pasteur, Department of Developmental and Stem Cell Biology, CNRS URA2578, 75015 Paris, France
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107
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Robinson AS, Materna SC, Barnes RM, De Val S, Xu SM, Black BL. An arterial-specific enhancer of the human endothelin converting enzyme 1 (ECE1) gene is synergistically activated by Sox17, FoxC2, and Etv2. Dev Biol 2014; 395:379-389. [PMID: 25179465 DOI: 10.1016/j.ydbio.2014.08.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 08/19/2014] [Indexed: 11/19/2022]
Abstract
Endothelin-converting enzyme-1 (Ece-1), a crucial component of the Endothelin signaling pathway, is required for embryonic development and is an important regulator of vascular tone, yet the transcriptional regulation of the ECE1 gene has remained largely unknown. Here, we define the activity and regulation of an enhancer from the human ECE1 locus in vivo. The enhancer identified here becomes active in endothelial progenitor cells shortly after their initial specification and is dependent on a conserved FOX:ETS motif, a composite binding site for Forkhead transcription factors and the Ets transcription factor Etv2, for activity in vivo. The ECE1 FOX:ETS motif is bound and cooperatively activated by FoxC2 and Etv2, but unlike other described FOX:ETS-dependent enhancers, ECE1 enhancer activity becomes restricted to arterial endothelium and endocardium by embryonic day 9.5 in transgenic mouse embryos. The ECE1 endothelial enhancer also contains an evolutionarily-conserved, consensus SOX binding site, which is required for activity in transgenic mouse embryos. Importantly, the ECE1 SOX site is bound and activated by Sox17, a transcription factor involved in endothelial cell differentiation and an important regulator of arterial identity. Moreover, the ECE1 enhancer is cooperatively activated by the combinatorial action of FoxC2, Etv2, and Sox17. Although Sox17 is required for arterial identity, few direct transcriptional targets have been identified in endothelial cells. Thus, this work has important implications for our understanding of endothelial specification and arterial subspecification.
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Affiliation(s)
- Ashley S Robinson
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
| | - Stefan C Materna
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
| | - Ralston M Barnes
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
| | - Sarah De Val
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
| | - Shan-Mei Xu
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
| | - Brian L Black
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2517
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108
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Early lineage restriction in temporally distinct populations of Mesp1 progenitors during mammalian heart development. Nat Cell Biol 2014; 16:829-40. [PMID: 25150979 DOI: 10.1038/ncb3024] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 07/10/2014] [Indexed: 12/16/2022]
Abstract
Cardiac development arises from two sources of mesoderm progenitors, the first heart field (FHF) and the second (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, whereas SHF progenitors were either unipotent or bipotent. Microarray and single-cell PCR with reverse transcription analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Together, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occur very early during gastrulation.
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109
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An updated view on the differentiation of stem cells into endothelial cells. SCIENCE CHINA-LIFE SCIENCES 2014; 57:763-73. [DOI: 10.1007/s11427-014-4712-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 06/16/2014] [Indexed: 12/16/2022]
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110
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Clowes C, Boylan MGS, Ridge LA, Barnes E, Wright JA, Hentges KE. The functional diversity of essential genes required for mammalian cardiac development. Genesis 2014; 52:713-37. [PMID: 24866031 PMCID: PMC4141749 DOI: 10.1002/dvg.22794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 05/22/2014] [Accepted: 05/23/2014] [Indexed: 01/04/2023]
Abstract
Genes required for an organism to develop to maturity (for which no other gene can compensate) are considered essential. The continuing functional annotation of the mouse genome has enabled the identification of many essential genes required for specific developmental processes including cardiac development. Patterns are now emerging regarding the functional nature of genes required at specific points throughout gestation. Essential genes required for development beyond cardiac progenitor cell migration and induction include a small and functionally homogenous group encoding transcription factors, ligands and receptors. Actions of core cardiogenic transcription factors from the Gata, Nkx, Mef, Hand, and Tbx families trigger a marked expansion in the functional diversity of essential genes from midgestation onwards. As the embryo grows in size and complexity, genes required to maintain a functional heartbeat and to provide muscular strength and regulate blood flow are well represented. These essential genes regulate further specialization and polarization of cell types along with proliferative, migratory, adhesive, contractile, and structural processes. The identification of patterns regarding the functional nature of essential genes across numerous developmental systems may aid prediction of further essential genes and those important to development and/or progression of disease. genesis 52:713–737, 2014.
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Affiliation(s)
- Christopher Clowes
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, United Kingdom
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111
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Glenn NO, Schumacher JA, Kim HJ, Zhao EJ, Skerniskyte J, Sumanas S. Distinct regulation of the anterior and posterior myeloperoxidase expression by Etv2 and Gata1 during primitive Granulopoiesis in zebrafish. Dev Biol 2014; 393:149-159. [PMID: 24956419 DOI: 10.1016/j.ydbio.2014.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 06/11/2014] [Accepted: 06/13/2014] [Indexed: 12/26/2022]
Abstract
Neutrophilic granulocytes are the most abundant type of myeloid cells and form an essential part of the innate immune system. In vertebrates the first neutrophils are thought to originate during primitive hematopoiesis, which precedes hematopoietic stem cell formation. In zebrafish embryos, it has been suggested that primitive neutrophils may originate in two distinct sites, the anterior (ALPM) and posterior lateral plate mesoderm (PLPM). An ETS-family transcription factor Etsrp/Etv2/ER71 has been implicated in vasculogenesis and hematopoiesis in multiple vertebrates. However, its role during neutrophil development is not well understood. Here we demonstrate using zebrafish embryos that Etv2 has a specific cell-autonomous function during primitive neutropoiesis in the anterior lateral plate mesoderm (ALPM) but has little effect on erythropoiesis or the posterior lateral plate mesoderm (PLPM) expression of neutrophil marker myeloperoxidase mpo/mpx. Our results argue that ALPM-derived neutrophils originate from etv2-expressing cells which downregulate etv2 during neutropoiesis. We further show that Scl functions downstream of Etv2 in anterior neutropoiesis. Additionally, we demonstrate that mpx expression within the PLPM overlaps with gata1 expression, potentially marking the cells with a dual myelo-erythroid potential. Intriguingly, initiation of mpx expression in the PLPM is dependent on gata1 but not etv2 function. Our results demonstrate that mpx expression is controlled differently in the ALPM and PLPM regions and describe novel roles for etv2 and gata1 during primitive neutropoiesis.
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Affiliation(s)
- Nicole O Glenn
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
| | - Jennifer A Schumacher
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
| | - Hyon J Kim
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
| | - Emma J Zhao
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
| | - Jurate Skerniskyte
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
| | - Saulius Sumanas
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA
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112
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Behrens AN, Zierold C, Shi X, Ren Y, Koyano-Nakagawa N, Garry DJ, Martin CM. Sox7 is regulated by ETV2 during cardiovascular development. Stem Cells Dev 2014; 23:2004-13. [PMID: 24762086 DOI: 10.1089/scd.2013.0525] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Vasculogenesis/angiogenesis is one of the earliest processes that occurs during embryogenesis. ETV2 and SOX7 were previously shown to play a role in endothelial development; however, their mechanistic interaction has not been defined. In the present study, concomitant expression of Etv2 and Sox7 in endothelial progenitor cells was verified. ETV2 was shown to be a direct upstream regulator of Sox7 that binds to ETV2 binding elements in the Sox7 upstream regulatory region and activates transcription. We observed that SOX7 over-expression can mimic ETV2 and increase endothelial progenitor cells in embryonic bodies (EBs), while knockdown of Sox7 is able to block ETV2-induced increase in endothelial progenitor cell formation. Angiogenic sprouting was increased by ETV2 over-expression in EBs, and it was significantly decreased in the presence of Sox7 shRNA. Collectively, these studies support the conclusion that ETV2 directly regulates Sox7, and that ETV2 governs endothelial development by regulating transcriptional networks which include Sox7.
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Affiliation(s)
- Ann N Behrens
- Lillehei Heart Institute, University of Minnesota , Minneapolis, Minnesota
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113
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Abedin MJ, Nguyen A, Jiang N, Perry CE, Shelton JM, Watson DK, Ferdous A. Fli1 acts downstream of Etv2 to govern cell survival and vascular homeostasis via positive autoregulation. Circ Res 2014; 114:1690-9. [PMID: 24727028 DOI: 10.1161/circresaha.1134303145] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Cardiovascular health depends on proper development and integrity of blood vessels. Ets variant 2 (Etv2), a member of the E26 transforming-specific family of transcription factors, is essential to initiate a transcriptional program leading to vascular morphogenesis in early mouse embryos. However, endothelial expression of the Etv2 gene ceases at midgestation; therefore, vascular development past this stage must continue independent of Etv2. OBJECTIVE To identify molecular mechanisms underlying transcriptional regulation of vascular morphogenesis and homeostasis in the absence of Etv2. METHODS AND RESULTS Using loss- and gain-of-function strategies and a series of molecular techniques, we identify Friend leukemia integration 1 (Fli1), another E26 transforming-specific family transcription factor, as a downstream target of Etv2. We demonstrate that Etv2 binds to conserved Ets-binding sites within the promoter region of the Fli1 gene and governs Fli1 expression. Importantly, in the absence of Etv2 at midgestation, binding of Etv2 at Ets-binding sites in the Fli1 promoter is replaced by Fli1 protein itself, sustaining expression of Fli1 as well as selective Etv2-regulated endothelial genes to promote endothelial cell survival and vascular integrity. Consistent with this, we report that Fli1 binds to the conserved Ets-binding sites within promoter and enhancer regions of other Etv2-regulated endothelial genes, including Tie2, to control their expression at and beyond midgestation. CONCLUSIONS We have identified a novel positive feed-forward regulatory loop in which Etv2 activates expression of genes involved in vasculogenesis, including Fli1. Once the program is activated in early embryos, Fli1 then takes over to sustain the process in the absence of Etv2.
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Affiliation(s)
- Md J Abedin
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - Annie Nguyen
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - Nan Jiang
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - Cameron E Perry
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - John M Shelton
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - Dennis K Watson
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.)
| | - Anwarul Ferdous
- From the Department of Internal Medicine (Cardiology) (M.J.A., A.N., N.J., C.E.P., J.M.S., A.F.), University of Texas Southwestern Medical Center, Dallas; Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston (D.K.W.); and Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis (M.J.A.).
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114
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Cooperative interaction of Etv2 and Gata2 regulates the development of endothelial and hematopoietic lineages. Dev Biol 2014; 389:208-18. [PMID: 24583263 DOI: 10.1016/j.ydbio.2014.02.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 02/07/2014] [Accepted: 02/19/2014] [Indexed: 12/31/2022]
Abstract
Regulatory mechanisms that govern lineage specification of the mesodermal progenitors to become endothelial and hematopoietic cells remain an area of intense interest. Both Ets and Gata factors have been shown to have important roles in the transcriptional regulation in endothelial and hematopoietic cells. We previously reported Etv2 as an essential regulator of vasculogenesis and hematopoiesis. In the present study, we demonstrate that Gata2 is co-expressed and interacts with Etv2 in the endothelial and hematopoietic cells in the early stages of embryogenesis. Our studies reveal that Etv2 interacts with Gata2 in vitro and in vivo. The protein-protein interaction between Etv2 and Gata2 is mediated by the Ets and Gata domains. Using the embryoid body differentiation system, we demonstrate that co-expression of Gata2 augments the activity of Etv2 in promoting endothelial and hematopoietic lineage differentiation. We also identify Spi1 as a common downstream target gene of Etv2 and Gata2. We provide evidence that Etv2 and Gata2 bind to the Spi1 promoter in vitro and in vivo. In summary, we propose that Gata2 functions as a cofactor of Etv2 in the transcriptional regulation of mesodermal progenitors during embryogenesis.
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115
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Chan SSK, Shi X, Toyama A, Arpke RW, Dandapat A, Iacovino M, Kang J, Le G, Hagen HR, Garry DJ, Kyba M. Mesp1 patterns mesoderm into cardiac, hematopoietic, or skeletal myogenic progenitors in a context-dependent manner. Cell Stem Cell 2014; 12:587-601. [PMID: 23642367 DOI: 10.1016/j.stem.2013.03.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 12/12/2012] [Accepted: 03/14/2013] [Indexed: 02/07/2023]
Abstract
Mesp1 is regarded as the master regulator of cardiovascular development, initiating the cardiac transcription factor cascade to direct the generation of cardiac mesoderm. To define the early embryonic cell population that responds to Mesp1, we performed pulse inductions of gene expression over tight temporal windows following embryonic stem cell differentiation. Remarkably, instead of promoting cardiac differentiation in the initial wave of mesoderm, Mesp1 binds to the Tal1 (Scl) +40 kb enhancer and generates Flk-1+ precursors expressing Etv2 (ER71) and Tal1 that undergo hematopoietic differentiation. The second wave of mesoderm responds to Mesp1 by differentiating into PDGFRα+ precursors that undergo cardiac differentiation. Furthermore, in the absence of serum-derived factors, Mesp1 promotes skeletal myogenic differentiation. Lineage tracing revealed that the majority of yolk sac and many adult hematopoietic cells derive from Mesp1+ precursors. Thus, Mesp1 is a context-dependent determination factor, integrating the stage of differentiation and the signaling environment to specify different lineage outcomes.
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Affiliation(s)
- Sunny Sun-Kin Chan
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
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116
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Findlay VJ, LaRue AC, Turner DP, Watson PM, Watson DK. Understanding the role of ETS-mediated gene regulation in complex biological processes. Adv Cancer Res 2014; 119:1-61. [PMID: 23870508 DOI: 10.1016/b978-0-12-407190-2.00001-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ets factors are members of one of the largest families of evolutionarily conserved transcription factors, regulating critical functions in normal cell homeostasis, which when perturbed contribute to tumor progression. The well-documented alterations in ETS factor expression and function during cancer progression result in pleiotropic effects manifested by the downstream effect on their target genes. Multiple ETS factors bind to the same regulatory sites present on target genes, suggesting redundant or competitive functions. The anti- and prometastatic signatures obtained by examining specific ETS regulatory networks will significantly improve our ability to accurately predict tumor progression and advance our understanding of gene regulation in cancer. Coordination of multiple ETS gene functions also mediates interactions between tumor and stromal cells and thus contributes to the cancer phenotype. As such, these new insights may provide a novel view of the ETS gene family as well as a focal point for studying the complex biological control involved in tumor progression. One of the goals of molecular biology is to elucidate the mechanisms that contribute to the development and progression of cancer. Such an understanding of the molecular basis of cancer will provide new possibilities for: (1) earlier detection, as well as better diagnosis and staging of disease; (2) detection of minimal residual disease recurrences and evaluation of response to therapy; (3) prevention; and (4) novel treatment strategies. Increased understanding of ETS-regulated biological pathways will directly impact these areas.
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Affiliation(s)
- Victoria J Findlay
- Department of Pathology and Laboratory Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, USA
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117
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Heart field origin of great vessel precursors relies on nkx2.5-mediated vasculogenesis. Nat Cell Biol 2013; 15:1362-9. [PMID: 24161929 PMCID: PMC3864813 DOI: 10.1038/ncb2862] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 09/18/2013] [Indexed: 01/12/2023]
Abstract
The pharyngeal arch arteries (PAAs) are transient embryonic blood vessels that make indispensable contributions to the carotid arteries and great vessels of the heart, including the aorta and pulmonary artery1, 2. During embryogenesis, the PAAs appear in a craniocaudal sequence to connect pre-existing segments of the primitive circulation after de novo vasculogenic assembly from angioblast precursors3, 4. Despite the unique spatiotemporal characteristics of PAA development, the embryonic origins of PAA angioblasts and the genetic factors regulating their emergence remain unknown. Here, we identify the embryonic source of PAA endothelium as nkx2.5+ progenitors in lateral plate mesoderm long considered to adopt cell fates within the heart exclusively5, 6. Further, we report that PAA endothelial differentiation relies on Nkx2.5, a canonical cardiac transcription factor not previously implicated in blood vessel formation. Together, these studies reveal the heart field origin of PAA endothelium and attribute a novel vasculogenic function to the cardiac transcription factor nkx2.5 during great vessel precursor development.
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118
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Moore JC, Sheppard-Tindell S, Shestopalov IA, Yamazoe S, Chen JK, Lawson ND. Post-transcriptional mechanisms contribute to Etv2 repression during vascular development. Dev Biol 2013; 384:128-40. [PMID: 24036310 DOI: 10.1016/j.ydbio.2013.08.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 08/05/2013] [Accepted: 08/30/2013] [Indexed: 01/08/2023]
Abstract
etv2 is an endothelial-specific ETS transcription factor that is essential for vascular differentiation and morphogenesis in vertebrates. While recent data suggest that Etv2 is dynamically regulated during vascular development, little is known about the mechanisms involved in this process. Here, we find that etv2 transcript and protein expression are highly dynamic during zebrafish vascular development, with both apparent during early somitogenesis and subsequently down-regulated as development proceeds. Inducible knockdown of Etv2 in zebrafish embryos prior to mid-somitogenesis stages, but not later, caused severe vascular defects, suggesting a specific role in early commitment of lateral mesoderm to the endothelial linage. Accordingly, Etv2-overexpressing cells showed an enhanced ability to commit to endothelial lineages in mosaic embryos. We further find that the etv2 3' untranslated region (UTR) is capable of repressing an endothelial autonomous transgene and contains binding sites for members of the let-7 family of microRNAs. Ectopic expression of let-7a could repress the etv2 3'UTR in sensor assays and was also able to block endogenous Etv2 protein expression, leading to concomitant reduction of endothelial genes. Finally, we observed that Etv2 protein levels persisted in maternal-zygotic dicer1 mutant embryos, suggesting that microRNAs contribute to its repression during vascular development. Taken together, our results suggest that etv2 acts during early development to specify endothelial lineages and is then down-regulated, in part through post-transcriptional repression by microRNAs, to allow normal vascular development.
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Affiliation(s)
- John C Moore
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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119
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Driving vascular endothelial cell fate of human multipotent Isl1+ heart progenitors with VEGF modified mRNA. Cell Res 2013; 23:1172-86. [PMID: 24018375 PMCID: PMC3790234 DOI: 10.1038/cr.2013.112] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 03/12/2013] [Accepted: 04/30/2013] [Indexed: 12/17/2022] Open
Abstract
Distinct families of multipotent heart progenitors play a central role in the generation of diverse cardiac, smooth muscle and endothelial cell lineages during mammalian cardiogenesis. The identification of precise paracrine signals that drive the cell-fate decision of these multipotent progenitors, and the development of novel approaches to deliver these signals in vivo, are critical steps towards unlocking their regenerative therapeutic potential. Herein, we have identified a family of human cardiac endothelial intermediates located in outflow tract of the early human fetal hearts (OFT-ECs), characterized by coexpression of Isl1 and CD144/vWF. By comparing angiocrine factors expressed by the human OFT-ECs and non-cardiac ECs, vascular endothelial growth factor (VEGF)-A was identified as the most abundantly expressed factor, and clonal assays documented its ability to drive endothelial specification of human embryonic stem cell (ESC)-derived Isl1+ progenitors in a VEGF receptor-dependent manner. Human Isl1-ECs (endothelial cells differentiated from hESC-derived ISL1+ progenitors) resemble OFT-ECs in terms of expression of the cardiac endothelial progenitor- and endocardial cell-specific genes, confirming their organ specificity. To determine whether VEGF-A might serve as an in vivo cell-fate switch for human ESC-derived Isl1-ECs, we established a novel approach using chemically modified mRNA as a platform for transient, yet highly efficient expression of paracrine factors in cardiovascular progenitors. Overexpression of VEGF-A promotes not only the endothelial specification but also engraftment, proliferation and survival (reduced apoptosis) of the human Isl1+ progenitors in vivo. The large-scale derivation of cardiac-specific human Isl1-ECs from human pluripotent stem cells, coupled with the ability to drive endothelial specification, engraftment, and survival following transplantation, suggest a novel strategy for vascular regeneration in the heart.
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120
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Palpant NJ, Pabon L, Rabinowitz JS, Hadland BK, Stoick-Cooper CL, Paige SL, Bernstein ID, Moon RT, Murry CE. Transmembrane protein 88: a Wnt regulatory protein that specifies cardiomyocyte development. Development 2013; 140:3799-808. [PMID: 23924634 DOI: 10.1242/dev.094789] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Genetic regulation of the cell fate transition from lateral plate mesoderm to the specification of cardiomyocytes requires suppression of Wnt/β-catenin signaling, but the mechanism for this is not well understood. By analyzing gene expression and chromatin dynamics during directed differentiation of human embryonic stem cells (hESCs), we identified a suppressor of Wnt/β-catenin signaling, transmembrane protein 88 (TMEM88), as a potential regulator of cardiovascular progenitor cell (CVP) specification. During the transition from mesoderm to the CVP, TMEM88 has a chromatin signature of genes that mediate cell fate decisions, and its expression is highly upregulated in advance of key cardiac transcription factors in vitro and in vivo. In early zebrafish embryos, tmem88a is expressed broadly in the lateral plate mesoderm, including the bilateral heart fields. Short hairpin RNA targeting of TMEM88 during hESC cardiac differentiation increases Wnt/β-catenin signaling, confirming its role as a suppressor of this pathway. TMEM88 knockdown has no effect on NKX2.5 or GATA4 expression, but 80% of genes most highly induced during CVP development have reduced expression, suggesting adoption of a new cell fate. In support of this, analysis of later stage cell differentiation showed that TMEM88 knockdown inhibits cardiomyocyte differentiation and promotes endothelial differentiation. Taken together, TMEM88 is crucial for heart development and acts downstream of GATA factors in the pre-cardiac mesoderm to specify lineage commitment of cardiomyocyte development through inhibition of Wnt/β-catenin signaling.
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Affiliation(s)
- Nathan J Palpant
- Department of Pathology, University of Washington, Seattle, WA 98195-7470, USA
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121
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Abstract
The establishment and maintenance of the vascular system is critical for embryonic development and postnatal life. Defects in endothelial cell development and vessel formation and function lead to embryonic lethality and are important in the pathogenesis of vascular diseases. Here, we review the underlying molecular mechanisms of endothelial cell differentiation, plasticity, and the development of the vasculature. This review focuses on the interplay among transcription factors and signaling molecules that specify the differentiation of vascular endothelial cells. We also discuss recent progress on reprogramming of somatic cells toward distinct endothelial cell lineages and its promise in regenerative vascular medicine.
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Affiliation(s)
- Changwon Park
- Department of Pharmacology, Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
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122
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Abstract
The circulatory system is the first organ system to develop in the vertebrate embryo and is critical throughout gestation for the delivery of oxygen and nutrients to, as well as removal of metabolic waste products from, growing tissues. Endothelial cells, which constitute the luminal layer of all blood and lymphatic vessels, emerge de novo from the mesoderm in a process known as vasculogenesis. The vascular plexus that is initially formed is then remodeled and refined via proliferation, migration, and sprouting of endothelial cells to form new vessels from preexisting ones during angiogenesis. Mural cells are also recruited by endothelial cells to form the surrounding vessel wall. During this vascular remodeling process, primordial endothelial cells are specialized to acquire arterial, venous, and blood-forming hemogenic phenotypes and functions. A subset of venous endothelium is also specialized to become lymphatic endothelium later in development. The specialization of all endothelial cell subtypes requires extrinsic signals and intrinsic regulatory events, which will be discussed in this review.
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Affiliation(s)
- Kathrina L Marcelo
- Interdepartmental Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
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123
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Veldman MB, Zhao C, Gomez GA, Lindgren AG, Huang H, Yang H, Yao S, Martin BL, Kimelman D, Lin S. Transdifferentiation of fast skeletal muscle into functional endothelium in vivo by transcription factor Etv2. PLoS Biol 2013; 11:e1001590. [PMID: 23853546 PMCID: PMC3708712 DOI: 10.1371/journal.pbio.1001590] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 05/09/2013] [Indexed: 02/05/2023] Open
Abstract
Etv2, a master regulator of endothelial cell fate, can induce fast skeletal muscle cells to transdifferentiate into endothelial cells in the zebrafish embryo. Etsrp/Etv2 (Etv2) is an evolutionarily conserved master regulator of vascular development in vertebrates. Etv2 deficiency prevents the proper specification of the endothelial cell lineage, while its overexpression causes expansion of the endothelial cell lineage in the early embryo or in embryonic stem cells. We hypothesized that Etv2 alone is capable of transdifferentiating later somatic cells into endothelial cells. Using heat shock inducible Etv2 transgenic zebrafish, we demonstrate that Etv2 expression alone is sufficient to transdifferentiate fast skeletal muscle cells into functional blood vessels. Following heat treatment, fast skeletal muscle cells turn on vascular genes and repress muscle genes. Time-lapse imaging clearly shows that muscle cells turn on vascular gene expression, undergo dramatic morphological changes, and integrate into the existing vascular network. Lineage tracing and immunostaining confirm that fast skeletal muscle cells are the source of these newly generated vessels. Microangiography and observed blood flow demonstrated that this new vasculature is capable of supporting circulation. Using pharmacological, transgenic, and morpholino approaches, we further establish that the canonical Wnt pathway is important for induction of the transdifferentiation process, whereas the VEGF pathway provides a maturation signal for the endothelial fate. Additionally, overexpression of Etv2 in mammalian myoblast cells, but not in other cell types examined, induced expression of vascular genes. We have demonstrated in zebrafish that expression of Etv2 alone is sufficient to transdifferentiate fast skeletal muscle into functional endothelial cells in vivo. Given the evolutionarily conserved function of this transcription factor and the responsiveness of mammalian myoblasts to Etv2, it is likely that mammalian muscle cells will respond similarly. The endothelial cell is a specialized cell type that lines blood vessels. These cells are involved in normal cardiovascular function and become damaged in cardiovascular disease states such as atherosclerosis and stroke. We have discovered that developing muscle cells in the zebrafish embryo can be converted into endothelial cells by the expression of a transcription factor called Etv2. Etv2 normally functions during embryonic development to specify blood and blood vessels. When expressed in muscle cells, Etv2 induces the expression of genes that are normally expressed in endothelial cells; it also represses muscle gene expression. On expressing Etv2, muscle cells change shape and go on to form lumenized blood vessels that connect to the existing circulatory system and support blood flow. The Wnt and VEGF signaling pathways are required for this fate transformation. Our results suggest that muscle cells may be a viable source for the de novo generation of endothelial cells for use in transplantation therapies and they highlight signalling pathways that might be manipulated to improve the efficiency of this process in mammalian cells.
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Affiliation(s)
- Matthew B. Veldman
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Chengjian Zhao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Gustavo A. Gomez
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Anne G. Lindgren
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Haigen Huang
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Hanshuo Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Shaohua Yao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
| | - Benjamin L. Martin
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - David Kimelman
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Shuo Lin
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China
- Department of Molecular, Cell and Developmental Biology, University of California–Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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124
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Wang CH, Wang TM, Young TH, Lai YK, Yen ML. The critical role of ECM proteins within the human MSC niche in endothelial differentiation. Biomaterials 2013; 34:4223-34. [DOI: 10.1016/j.biomaterials.2013.02.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/20/2013] [Indexed: 12/20/2022]
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125
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Rasmussen TL, Martin CM, Walter CA, Shi X, Perlingeiro R, Koyano-Nakagawa N, Garry DJ. Etv2 rescues Flk1 mutant embryoid bodies. Genesis 2013; 51:471-80. [PMID: 23606617 DOI: 10.1002/dvg.22396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 03/29/2013] [Accepted: 04/11/2013] [Indexed: 01/24/2023]
Abstract
Independent mouse knockouts of Etv2 and Flk1 are embryonic lethal and lack hematopoietic and endothelial lineages. We previously reported that Flk1 activates Etv2 in the initiation of hematopoiesis and vasculogenesis. However, Flk1 and its ligand VEGF are expressed throughout development, from E7.0 to adulthood, whereas Etv2 is expressed only transiently during embryogenesis. These observations suggest a complex regulatory interaction between Flk1 and Etv2. To further examine the Flk1 and Etv2 regulatory interaction, we transduced Etv2 and Flk1 mutant ES cells with viral integrants that inducibly overexpress Flk1 or Etv2. We demonstrated that forced expression of Etv2 rescued the hematopoietic and endothelial potential of differentiating Flk1 and Etv2 mutant cells. We further discovered that forced expression of Flk1 can rescue that of the Flk1, but not Etv2 mutant cells. Therefore, we conclude that the requirement for Flk1 can be bypassed by expressing Etv2, supporting the notion that disruption of Etv2 expression is responsible for the early phenotypes of the Etv2 and Flk1 mutant embryos.
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Affiliation(s)
- Tara L Rasmussen
- Department of Medicine, Cardiovascular Division, and Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, USA
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126
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Koyano-Nakagawa N, Kweon J, Iacovino M, Shi X, Rasmussen TL, Borges L, Zirbes KM, Li T, Perlingeiro RCR, Kyba M, Garry DJ. Etv2 is expressed in the yolk sac hematopoietic and endothelial progenitors and regulates Lmo2 gene expression. Stem Cells 2013; 30:1611-23. [PMID: 22628281 DOI: 10.1002/stem.1131] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During embryogenesis, the endothelial and the hematopoietic lineages first appear during gastrulation in the blood island of the yolk sac. We have previously reported that an Ets variant gene 2 (Etv2/ER71) mutant embryo lacks hematopoietic and endothelial lineages; however, the precise roles of Etv2 in yolk sac development remains unclear. In this study, we define the role of Etv2 in yolk sac blood island development using the Etv2 mutant and a novel Etv2-EYFP reporter transgenic line. Both the hematopoietic and the endothelial lineages are absent in the Etv2 mutant yolk sac. In the Etv2-EYFP transgenic mouse, the EYFP reporter is activated in the nascent mesoderm, expressed in the endothelial and blood progenitors, and in the Tie2(+), c-kit(+), and CD41(+) hematopoietic population. The hematopoietic activity in the E7.75 yolk sac was exclusively localized to the Etv2-EYFP(+) population. In the Etv2 mutant yolk sac, Tie2(+) cells are present but do not express hematopoietic or endothelial markers. In addition, these cells do not form hematopoietic colonies, indicating an essential role of Etv2 in the specification of the hematopoietic lineage. Forced overexpression of Etv2 during embryoid body differentiation induces the hematopoietic and the endothelial lineages, and transcriptional profiling in this context identifies Lmo2 as a downstream target. Using electrophoretic mobility shift assay, chromatin immunoprecipitation, transcriptional assays, and mutagenesis, we demonstrate that Etv2 binds to the Lmo2 enhancer and transactivates its expression. Collectively, our studies demonstrate that Etv2 is expressed during and required for yolk sac hematoendothelial development, and that Lmo2 is one of the downstream targets of Etv2.
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Affiliation(s)
- Naoko Koyano-Nakagawa
- Lillehei Heart-Institute, Department of Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota 55455, USA
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127
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Nakano H, Nakano H, Liu X, Arshi A, Nakashima Y, van Handel B, Sasidharan R, Harmon AW, Shin JH, Schwartz RJ, Conway SJ, Harvey RP, Pashmforoush M, Mikkola HKA, Nakano A. Haemogenic endocardium contributes to transient definitive haematopoiesis. Nat Commun 2013; 4:1564. [PMID: 23463007 PMCID: PMC3612528 DOI: 10.1038/ncomms2569] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 01/31/2013] [Indexed: 12/11/2022] Open
Abstract
Haematopoietic cells arise from spatiotemporally restricted domains in the developing embryo. Although studies of non-mammalian animal and in vitro embryonic stem cell models suggest a close relationship among cardiac, endocardial and haematopoietic lineages, it remains unknown whether the mammalian heart tube serves as a haemogenic organ akin to the dorsal aorta. Here we examine the haemogenic activity of the developing endocardium. Mouse heart explants generate myeloid and erythroid colonies in the absence of circulation. Haemogenic activity arises from a subset of endocardial cells in the outflow cushion and atria earlier than in the aorta-gonad-mesonephros region, and is transient and definitive in nature. Interestingly, key cardiac transcription factors, Nkx2-5 and Isl1, are expressed in and required for the haemogenic population of the endocardium. Together, these data suggest that a subset of endocardial/endothelial cells serve as a de novo source for transient definitive haematopoietic progenitors.
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Affiliation(s)
- Haruko Nakano
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Haruko Nakano
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xiaoqian Liu
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Armin Arshi
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yasuhiro Nakashima
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ben van Handel
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Rajkumar Sasidharan
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andrew W. Harmon
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jae-Ho Shin
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Robert J. Schwartz
- Department of Biology and Biochemistry, University of Houston, Houston, 77204, USA
| | - Simon J. Conway
- Departments of Anatomy & Cell Biology, Medical & Molecular Genetics, Biochemistry & Molecular Biology, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Richard P. Harvey
- Developmental Biology Division, the Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, 2010, Australia
- St Vincent's Clinical School, University of New South Wales, Australia
| | - Mohammad Pashmforoush
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California Keck School of Medicine, 90089
| | - Hanna K. A. Mikkola
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Atsushi Nakano
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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128
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Behrens AN, Ren Y, Ferdous A, Garry DJ, Martin CM. Nkx2-5 Regulates Tdgf1 (Cripto) Early During Cardiac Development. ACTA ACUST UNITED AC 2013; Suppl 11:1-4. [PMID: 24069547 DOI: 10.4172/2155-9880.s11-003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Congenital Heart Disease (CHD) is the most frequent and deadly birth defect. Patients with CHD that survive the neonatal period often progress to develop advanced heart failure requiring specialized treatment including cardiac transplantation. A full understanding of the transcriptional networks that direct cardiac progenitors during heart development will enhance our understanding of both normal cardiac function and pathological states. These findings will also have important applications for emerging therapies and the treatment of congenital heart disease. Furthermore, a number of shared transcriptional pathways or networks have been proposed to regulate the development and regeneration of tissues such as the heart. We have utilized transgenic technology to isolate and characterize cardiac progenitor cells from the developing mouse heart and have begun to define specific transcriptional networks of cardiovascular development. Initial studies identified Tdgf1 as a potential target of Nkx2-5. To mechanistically dissect the regulation of this molecular program, we utilized an array of molecular biological techniques to confirm that Nkx2-5 is an upstream regulator of the Tdgf1 gene in early cardiac development. These studies further define Nkx2-5 mediated transcriptional networks and enhance our understanding of cardiac morphogenesis.
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Affiliation(s)
- Ann N Behrens
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, USA
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129
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Van Vliet P, Wu SM, Zaffran S, Pucéat M. Early cardiac development: a view from stem cells to embryos. Cardiovasc Res 2012; 96:352-62. [PMID: 22893679 PMCID: PMC3500045 DOI: 10.1093/cvr/cvs270] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/24/2012] [Accepted: 08/09/2012] [Indexed: 12/11/2022] Open
Abstract
From the 1920s, early cardiac development has been studied in chick and, later, in mouse embryos in order to understand the first cell fate decisions that drive specification and determination of the endocardium, myocardium, and epicardium. More recently, mouse and human embryonic stem cells (ESCs) have demonstrated faithful recapitulation of early cardiogenesis and have contributed significantly to this research over the past few decades. Derived almost 15 years ago, human ESCs have provided a unique developmental model for understanding the genetic and epigenetic regulation of early human cardiogenesis. Here, we review the biological concepts underlying cell fate decisions during early cardiogenesis in model organisms and ESCs. We draw upon both pioneering and recent studies and highlight the continued role for in vitro stem cells in cardiac developmental biology.
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Affiliation(s)
- Patrick Van Vliet
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, CA, USA
| | - Sean M. Wu
- Department of Medicine, Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Cambridge, MA, USA
| | - Stéphane Zaffran
- Aix-Marseille University, Marseille, France
- INSERM UMRS910, Faculté de Médecine de la Timone, France
| | - Michel Pucéat
- INSERM UMR633, Paris Descartes University, Campus Genopole 1, 4, rue Pierre Fontaine, Evry 91058, Paris, France
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130
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Rasmussen TL, Shi X, Wallis A, Kweon J, Zirbes KM, Koyano-Nakagawa N, Garry DJ. VEGF/Flk1 signaling cascade transactivates Etv2 gene expression. PLoS One 2012. [PMID: 23185546 PMCID: PMC3501484 DOI: 10.1371/journal.pone.0050103] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Previous reports regarding the genetic hierarchy between Ets related protein 71 (Er71/Etv2) and Flk1 is unclear. In the present study, we pursued a genetic approach to define the molecular cascade between Etv2 and Flk1. Using a transgenic Etv2-EYFP reporter mouse, we examined the expression pattern of Etv2 relative to Flk1 in the early conceptus. Etv2-EYFP was expressed in subset of Flk1 positive cells during primitive streak stages, suggesting that Flk1 is upstream of Etv2 during gastrulation. Analysis of reporter gene expression in Flk1 and Etv2 mutant mice further supports the hypothesis that Flk1 is necessary for Etv2 expression. The frequency of cells expressing Flk1 in Etv2 mutants is only modestly altered (21% decrease), whereas expression of the Etv2-EYFP transgenic reporter was severely reduced in the Flk1 null background. We further demonstrate using transcriptional assays that, in the presence of Flk1, the Etv2 promoter is activated by VEGF, the Flk1 ligand. Pharmacological inhibition studies demonstrate that VEGF mediated activation is dependent on p38 MAPK, which activates Creb. We identify the VEGF response element in the Etv2 promoter and demonstrate that Creb binds to this motif by EMSA and ChIP assays. In summary, we provide new evidence that VEGF activates Etv2 by signaling through Flk1, which activates Creb through the p38 MAPK signaling cascade.
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Affiliation(s)
- Tara L. Rasmussen
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Xiaozhong Shi
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Alicia Wallis
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Junghun Kweon
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Katie M. Zirbes
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Naoko Koyano-Nakagawa
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Daniel J. Garry
- Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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131
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Embryological origin of the endocardium and derived valve progenitor cells: from developmental biology to stem cell-based valve repair. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:917-22. [PMID: 23078978 DOI: 10.1016/j.bbamcr.2012.09.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 09/26/2012] [Accepted: 09/29/2012] [Indexed: 11/23/2022]
Abstract
The cardiac valves are targets of both congenital and acquired diseases. The formation of valves during embryogenesis (i.e., valvulogenesis) originates from endocardial cells lining the myocardium. These cells undergo an endothelial-mesenchymal transition, proliferate and migrate within an extracellular matrix. This leads to the formation of bilateral cardiac cushions in both the atrioventricular canal and the outflow tract. The embryonic origin of both the endocardium and prospective valve cells is still elusive. Endocardial and myocardial lineages are segregated early during embryogenesis and such a cell fate decision can be recapitulated in vitro by embryonic stem cells (ESC). Besides genetically modified mice and ex vivo heart explants, ESCs provide a cellular model to study the early steps of valve development and might constitute a human therapeutic cell source for decellularized tissue-engineered valves. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.
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132
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Wareing S, Eliades A, Lacaud G, Kouskoff V. ETV2 expression marks blood and endothelium precursors, including hemogenic endothelium, at the onset of blood development. Dev Dyn 2012; 241:1454-64. [PMID: 22733530 DOI: 10.1002/dvdy.23825] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2012] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND ETV2 has been identified as an important player in embryonic hematopoiesis. However, the cell populations in which this transcription factor is expressed and operates during blood specification remain to be fully characterized. Here we address these issues using ES cells and a transgenic mouse line expressing green fluorescent protein (GFP) under the control of ETV2 regulatory elements, allowing us to observe the tight association between ETV2 expression and the initiation of hematopoiesis. RESULTS Both in differentiating ES cells and gastrulating embryos ETV2::GFP is mostly found co-expressed with endothelial markers and defines a subset of cells with greatly enriched primitive erythroid potential. Upon culture ETV2::GFP cells rapidly up-regulate CD41, down-regulate endothelium cell surface markers and generate definitive hematopoietic progenitors. Altogether these characteristics represent the hallmark of hemogenic endothelium cells, a specialized endothelium originating from the hemangioblast and giving rise to hematopoietic cells. Importantly, ETV2 deficiency results in a complete absence of hemogenic endothelium in differentiating ES cells and gastrulating embryos. CONCLUSIONS Altogether our data reveal that ETV2 marks hemogenic endothelium in gastrulating embryos and is absolutely required for the formation of this precursor at the onset of hematopoiesis. These results enhance our understanding of embryonic hematopoiesis and the factors driving hemogenic endothelium specification.
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Affiliation(s)
- Sarah Wareing
- Cancer Research UK Stem Cell Hematopoiesis Group, Paterson Institute for Cancer Research, University of Manchester, Manchester, UK
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133
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Regulation of endothelial and hematopoietic development by the ETS transcription factor Etv2. Curr Opin Hematol 2012; 19:199-205. [PMID: 22406820 DOI: 10.1097/moh.0b013e3283523e07] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE OF REVIEW Vasculogenesis and hematopoiesis are essential for development. Recently, the ETS domain transcription factor Etv2 has been identified as an essential regulator of vasculogenesis and hematopoiesis. Here, we review the recent studies that have established the critical role of Etv2 in the specification of mesoderm to blood and endothelial cells. RECENT FINDINGS Loss and gain-of-function studies have demonstrated the conserved role of Etv2 in endothelial and hematopoietic development. Recent studies have placed Etv2 at or near the top of the hierarchy in specification of these lineages and have begun to dissect the upstream regulators and downstream effectors of Etv2 function using multiple model organisms and experimental systems. SUMMARY Etv2 is essential for the specification of endothelial and hematopoietic lineages. Understanding the mechanisms through which Etv2 specifies endothelial and blood cells by defining upstream transcriptional regulators and cofactors will lead to greater insight into vasculogenesis and hematopoiesis, and may help to identify therapeutic targets to treat vascular disorders or to promote or inhibit vessel growth.
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134
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Yamamizu K, Matsunaga T, Katayama S, Kataoka H, Takayama N, Eto K, Nishikawa SI, Yamashita JK. PKA/CREB signaling triggers initiation of endothelial and hematopoietic cell differentiation via Etv2 induction. Stem Cells 2012; 30:687-96. [PMID: 22267325 DOI: 10.1002/stem.1041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Ets family protein Etv2 (also called ER71 or Etsrp) is a key factor for initiation of vascular and blood development from mesodermal cells. However, regulatory mechanisms and inducing signals for Etv2 expression have been largely unknown. Previously, we revealed that cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling enhanced differentiation of vascular progenitors into endothelial cells (ECs) and hematopoietic cells (HPCs) using an embryonic stem cell (ESC) differentiation system. Here, we show that PKA activation in an earlier differentiation stage can trigger EC/HPC differentiation through Etv2 induction. We found Etv2 was markedly upregulated by PKA activation preceding EC and HPC differentiation. We identified two cAMP response element (CRE) sequences in the Etv2 promoter and 5'-untranslated region and confirmed that CRE-binding protein (CREB) directly binds to the CRE sites and activates Etv2 transcription. Expression of a dominant negative form of CREB completely inhibited PKA-elicited Etv2 expression and induction of EC/HPCs from ESCs. Furthermore, blockade of PKA significantly inhibited Etv2 expression in ex vivo whole-embryo culture using Etv2-Venus knockin mice. These data indicated that PKA/CREB pathway is a critical regulator for the initiation of EC/HPC differentiation via Etv2 transcription. This early-stage molecular linkage between a triggering signal and transcriptional cascades for differentiation would provide novel insights in vascular and blood development and cell fate determination.
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Affiliation(s)
- Kohei Yamamizu
- Laboratory of Stem Cell Differentiation, Stem Cell Research Center, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan; Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
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135
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DiTacchio L, Bowles J, Shin S, Lim DS, Koopman P, Janknecht R. Transcription factors ER71/ETV2 and SOX9 participate in a positive feedback loop in fetal and adult mouse testis. J Biol Chem 2012; 287:23657-66. [PMID: 22613723 DOI: 10.1074/jbc.m111.320101] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
ER71, also known as ETV2, is an ETS transcription factor that is expressed during embryogenesis and in adult testes. We show that Er71 transcription can be up-regulated by SRY, the key determinant of male differentiation. Accordingly, SRY bound to and activated the Er71 promoter, and mutation of a putative SRY binding site abolished this promoter activation. In turn, ER71 was able to bind to the promoter of Sox9, the primary target of SRY and a critical transcription factor for maintenance of the Sertoli cell phenotype. Mutation of the ER71 binding site in the Sox9 promoter suppressed ER71-dependent up-regulation of Sox9 transcription, and a dominant-negative ER71 molecule severely reduced Sox9 transcription in a Sertoli cell line. Conversely, SOX9 bound the Er71 promoter in vivo and Sox9 down-regulation reduced Er71 transcript levels. Together, these data suggest a mechanism by which SRY induces Sox9 and Er71 transcription early in testis differentiation, whereas ER71 and SOX9 participate in an autoregulatory loop to sustain each other's expression after Sry expression has subsided in mice. Thereby, ER71 and SOX9 may affect late testis development as well as the function of the adult male gonad.
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136
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Nishikawa S. Hemangioblast: an in vitro phantom. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 1:603-8. [PMID: 23801536 DOI: 10.1002/wdev.38] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The hemangioblast, a bipotent progenitor that generates both endothelial cells (EC) and blood cells (BC) in the blood islands (BI) of the yolk sac (YS) has been a core notion of developmental hematology since the early 20th century. However, its actual presence has not been directly addressed for long. At the very end of the 20th century, the hemangioblast was revisited as a result of the development of new technologies that enable detection of such bipotent precursors in vitro. Such studies provided evidence for the presence of bipotent precursors for EC and BC. On the other hand, subsequent studies analyzing the processes occurring within BI strongly argued against the notion of hemanigioblasts and suggest that the hemangioblast is an in vitro artefact. In this article, I overview the history of the study of the hemangioblast and try to explain why hemangioblast that can be defined in vitro cannot be detected in BI.
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Affiliation(s)
- Shinichi Nishikawa
- Stem Cell Research Group, Riken Center for Developmental Biology, Kobe, Japan.
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137
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Abstract
The formation of the heart involves diversification of lineages which differentiate into distinct cardiac cell types or contribute to different regions such as the four cardiac chambers. The heart is the first organ to form in the embryo. However, in parallel with the growth of the organism, before or after birth, the heart has to adapt its size to maintain pumping efficiency. The adult heart has only a mild regeneration potential; thus, strategies to repair the heart after injury are based on the mobilisation of resident cardiac stem cells or the transplantation of external sources of stem cells. We discuss current knowledge on these aspects and raise questions for future research.
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138
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Palencia-Desai S, Kohli V, Kang J, Chi NC, Black BL, Sumanas S. Vascular endothelial and endocardial progenitors differentiate as cardiomyocytes in the absence of Etsrp/Etv2 function. Development 2011; 138:4721-32. [PMID: 21989916 DOI: 10.1242/dev.064998] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Previous studies have suggested that embryonic vascular endothelial, endocardial and myocardial lineages originate from multipotential cardiovascular progenitors. However, their existence in vivo has been debated and molecular mechanisms that regulate specification of different cardiovascular lineages are poorly understood. An ETS domain transcription factor Etv2/Etsrp/ER71 has been recently established as a crucial regulator of vascular endothelial differentiation in zebrafish and mouse embryos. In this study, we show that etsrp-expressing vascular endothelial/endocardial progenitors differentiate as cardiomyocytes in the absence of Etsrp function during zebrafish embryonic development. Expression of multiple endocardial specific markers is absent or greatly reduced in Etsrp knockdown or mutant embryos. We show that Etsrp regulates endocardial differentiation by directly inducing endocardial nfatc1 expression. In addition, Etsrp function is required to inhibit myocardial differentiation. In the absence of Etsrp function, etsrp-expressing endothelial and endocardial progenitors initiate myocardial marker hand2 and cmlc2 expression. Furthermore, Foxc1a function and interaction between Foxc1a and Etsrp is required to initiate endocardial development, but is dispensable for the inhibition of myocardial differentiation. These results argue that Etsrp initiates endothelial and endocardial, and inhibits myocardial, differentiation by two distinct mechanisms. Our findings are important for the understanding of genetic pathways that control cardiovascular differentiation during normal vertebrate development and will also greatly contribute to the stem cell research aimed at regenerating heart tissues.
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Affiliation(s)
- Sharina Palencia-Desai
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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139
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Rasmussen TL, Kweon J, Diekmann MA, Belema-Bedada F, Song Q, Bowlin K, Shi X, Ferdous A, Li T, Kyba M, Metzger JM, Koyano-Nakagawa N, Garry DJ. ER71 directs mesodermal fate decisions during embryogenesis. Development 2011; 138:4801-12. [PMID: 21989919 DOI: 10.1242/dev.070912] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Er71 mutant embryos are nonviable and lack hematopoietic and endothelial lineages. To further define the functional role for ER71 in cell lineage decisions, we generated genetically modified mouse models. We engineered an Er71-EYFP transgenic mouse model by fusing the 3.9 kb Er71 promoter to the EYFP reporter gene. Using FACS and transcriptional profiling, we examined the EYFP(+) population of cells in Er71 mutant and wild-type littermates. In the absence of ER71, we observed an increase in the number of EYFP-expressing cells, increased expression of the cardiac molecular program and decreased expression of the hemato-endothelial program, as compared with wild-type littermate controls. We also generated a novel Er71-Cre transgenic mouse model using the same 3.9 kb Er71 promoter. Genetic fate-mapping studies revealed that the ER71-expressing cells give rise to the hematopoietic and endothelial lineages in the wild-type background. In the absence of ER71, these cell populations contributed to alternative mesodermal lineages, including the cardiac lineage. To extend these analyses, we used an inducible embryonic stem/embryoid body system and observed that ER71 overexpression repressed cardiogenesis. Together, these studies identify ER71 as a critical regulator of mesodermal fate decisions that acts to specify the hematopoietic and endothelial lineages at the expense of cardiac lineages. This enhances our understanding of the mechanisms that govern mesodermal fate decisions early during embryogenesis.
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Affiliation(s)
- Tara L Rasmussen
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
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140
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Abstract
RATIONALE Endothelial cells are developmentally derived from angioblasts specified in the mesodermal germ cell layer. The transcription factor etsrp/etv2 is at the top of the known genetic hierarchy for angioblast development. The transcriptional events that induce etsrp expression and angioblast specification are not well understood. OBJECTIVE We generated etsrp:gfp transgenic zebrafish and used them to identify regulatory regions and transcription factors critical for etsrp expression and angioblast specification from mesoderm. METHODS AND RESULTS To investigate the mechanisms that initiate angioblast cell transcription during embryogenesis, we have performed promoter analysis of the etsrp locus in zebrafish. We describe three enhancer elements sufficient for endothelial gene expression when place in front of a heterologous promoter. The deletion of all 3 regulatory regions led to a near complete loss of endothelial expression from the etsrp promoter. One of the enhancers, located 2.3 kb upstream of etsrp contains a consensus FOX binding site that binds Foxc1a and Foxc1b in vitro by EMSA and in vivo using ChIP. Combined knockdown of foxc1a/b, using morpholinos, led to a significant decrease in etsrp expression at early developmental stages as measured by quantitative reverse transcriptase-polymerase chain reaction and in situ hybridization. Decreased expression of primitive erythrocyte genes scl and gata1 was also observed, whereas pronephric gene pax2a was relatively normal in expression level and pattern. CONCLUSIONS These findings identify mesodermal foxc1a/b as a direct upstream regulator of etsrp in angioblasts. This establishes a new molecular link in the process of mesoderm specification into angioblast.
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Affiliation(s)
- Matthew B Veldman
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, 621 Charles E Young Dr South, Los Angeles, CA 90095-1606, USA
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141
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Ishitobi H, Wakamatsu A, Liu F, Azami T, Hamada M, Matsumoto K, Kataoka H, Kobayashi M, Choi K, Nishikawa SI, Takahashi S, Ema M. Molecular basis for Flk1 expression in hemato-cardiovascular progenitors in the mouse. Development 2011; 138:5357-68. [PMID: 22071109 DOI: 10.1242/dev.065565] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The mouse Flk1 gene is expressed in various mesodermal progenitor cells of developing embryos. Recent studies have shown that Flk1 expression marks multipotent mesodermal progenitors, giving rise to various hemato-cardiovascular cell lineages during development. Flk1 expression also marks hemato-cardiovascular cell lineages in differentiating embryonic stem (ES) cells, which may be used in transplantation decisions to treat cardiovascular diseases. Despite its developmental and clinical importance in cardiovascular tissues, the transcriptional regulatory system of Flk1 has remained unclear. Here, we report a novel enhancer of the mouse Flk1 gene directing early mesodermal expression during development as well as ES differentiation. The enhancer enriches various mesodermal progenitors, such as primitive erythropoietic progenitors, hemangioblast (BL-CFC) and cardiovascular progenitors (CV-CFC). The enhancer is activated by Bmp, Wnt and Fgf, and it contains Gata-, Cdx-, Tcf/Lef-, ER71/Etv2- and Fox-binding sites, some of which are bound specifically by each of these transcription factors. As these transcription factors are known to act under the control of the Bmp, Wnt and Fgf families, early Flk1 expression may be induced by cooperative interactions between Gata, Tcf/Lef, Cdx and ER71/Etv2 under the control of Bmp, Wnt and Fgf signaling. The enhancer is required for early Flk1 expression and for hemangioblast development during ES differentiation.
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Affiliation(s)
- Hiroyuki Ishitobi
- Department of Anatomy and Embryology, Institute of Basic Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai,Tsukuba, Ibaraki, Japan
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142
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Murakami M, Nguyen LT, Hatanaka K, Schachterle W, Chen PY, Zhuang ZW, Black BL, Simons M. FGF-dependent regulation of VEGF receptor 2 expression in mice. J Clin Invest 2011; 121:2668-78. [PMID: 21633168 DOI: 10.1172/jci44762] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 04/13/2011] [Indexed: 01/19/2023] Open
Abstract
Numerous studies have suggested a link between the angiogenic FGF and VEGF signaling pathways; however, the nature of this link has not been established. To evaluate this relationship, we investigated VEGF signaling in ECs with disrupted FGF signaling in vitro and in vivo. ECs lacking FGF signaling became unresponsive to VEGF, caused by downregulation of VEGF receptor 2 (VEGFR2) expression after reduced Vegfr2 enhancer activation. FGF mediated VEGFR2 expression via activation of Erk1/2. Transcriptional analysis revealed that Ets transcription factors controlled VEGFR2 expression in an FGF- and Erk1/2-dependent manner. Mice with defective FGF signaling exhibited loss of vascular integrity and reduced vascular morphogenesis. Thus, basal FGF stimulation of the endothelium is required for maintenance of VEGFR2 expression and the ability to respond to VEGF stimulation and accounts for the hierarchic control of vascular formation by FGFs and VEGF.
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Affiliation(s)
- Masahiro Murakami
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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143
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Hollenhorst PC, McIntosh LP, Graves BJ. Genomic and biochemical insights into the specificity of ETS transcription factors. Annu Rev Biochem 2011; 80:437-71. [PMID: 21548782 DOI: 10.1146/annurev.biochem.79.081507.103945] [Citation(s) in RCA: 373] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
ETS proteins are a group of evolutionarily related, DNA-binding transcriptional factors. These proteins direct gene expression in diverse normal and disease states by binding to specific promoters and enhancers and facilitating assembly of other components of the transcriptional machinery. The highly conserved DNA-binding ETS domain defines the family and is responsible for specific recognition of a common sequence motif, 5'-GGA(A/T)-3'. Attaining specificity for biological regulation in such a family is thus a conundrum. We present the current knowledge of routes to functional diversity and DNA binding specificity, including divergent properties of the conserved ETS and PNT domains, the involvement of flanking structured and unstructured regions appended to these dynamic domains, posttranslational modifications, and protein partnerships with other DNA-binding proteins and coregulators. The review emphasizes recent advances from biochemical and biophysical approaches, as well as insights from genomic studies that detect ETS-factor occupancy in living cells.
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Affiliation(s)
- Peter C Hollenhorst
- Medical Sciences, Indiana University School of Medicine, Bloomington, Indiana 47405, USA.
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144
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Forkhead factor FoxO1 is essential for placental morphogenesis in the developing embryo. Proc Natl Acad Sci U S A 2011; 108:16307-12. [PMID: 21930913 DOI: 10.1073/pnas.1107341108] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Forkhead box O1 (FoxO1), a member of the Forkhead box-containing O family of transcription factors, is a key regulator of numerous genes that govern a wide array of cellular functions, including differentiation, homeostasis, and survival. However, the role of FoxO1 in development remains elusive. Here, we describe an essential and previously undefined role for FoxO1 in placental development. We demonstrate that FoxO1-null embryos up to embryonic day 9.0 (E9.0) are indistinguishable, including their morphology, cardiovascular structure, and vascular gene expression, from wild-type (WT) littermates. However, FoxO1-nulls manifested a profoundly swollen/hydropic allantois, which failed to fuse with the chorion, a phenotype that leads to subsequent cardiovascular malformation, progressive apoptotic cell death, and embryonic lethality at E10.5. Quantitative RT-PCR analysis of genes involved in placental development revealed significant attenuation of VCAM1 expression in FoxO1-null embryos. Using immunohistochemical, transcriptional, and chromatin immunoprecipitation assays, we further discovered that FoxO1 is an essential upstream regulator of the VCAM1 gene. Collectively, our findings provide critical molecular insight into a unique FoxO1-VCAM1 axis that governs placental morphogenesis, a process that is essential for subsequent normal cardiovascular development and fetal life.
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145
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Abstract
Etv2 (Ets Variant 2) has been shown to be an indispensable gene for the development of hematopoietic cells (HPCs)/endothelial cells (ECs). However, how Etv2 specifies the mesoderm-generating HPCs/ECs remains incompletely understood. In embryonic stem cell (ESC) differentiation culture and Etv2-null embryos, we show that Etv2 is dispensable for generating primitive Flk-1(+)/PDGFRα(+) mesoderm but is required for the progression of Flk-1(+)/PDGFRα(+) cells into vascular/hematopoietic mesoderm. Etv2-null ESCs and embryonic cells were arrested as Flk-1(+)/PDGFRα(+) and failed to generate Flk-1(+)/PDGFRα(-) mesoderm. Flk-1(+)/Etv2(+) early embryonic cells showed significantly higher hemato-endothelial potential than the Flk-1(+)/Etv2(-) population, suggesting that Etv2 specifies a hemato-endothelial subset of Flk-1(+) mesoderm. Critical hemato-endothelial genes were severely down-regulated in Etv2-null Flk-1(+) cells. Among those genes Scl, Fli1, and GATA2 were expressed simultaneously with Etv2 in early embryos and seemed to be critical targets. Etv2 reexpression in Etv2-null cells restored the development of CD41(+), CD45(+), and VE-cadherin(+) cells. Expression of Scl or Fli1 alone could also restore HPCs/ECs in the Etv2-null background, indicating that these 2 genes are critical downstream targets. Furthermore, VEGF induced Etv2 potently and rapidly in Flk-1(+) mesoderm. We propose that Flk-1(+)/PDGFRα(+) primitive mesoderm is committed into Flk-1(+)/PDGFRα(-) vascular mesoderm through Etv2 and that up-regulation of Etv2 by VEGF promotes this commitment.
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146
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De Val S. Key transcriptional regulators of early vascular development. Arterioscler Thromb Vasc Biol 2011; 31:1469-75. [PMID: 21677289 DOI: 10.1161/atvbaha.110.221168] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The formation of the vasculature depends on the precise spatial and temporal control of gene expression to define endothelial cell identity and to ensure the correct distribution and structure of the forming vessel network. This review provides an overview of the establishment of the vascular system, accompanied by a detailed discussion of the transcription factors involved in regulating endothelial gene expression during vasculogenesis and early vessel formation in both fish and mammalian systems. We also review the transcriptional pathways lying both upstream and downstream of key vascular transcription factors.
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Affiliation(s)
- Sarah De Val
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, Old Road Campus Research Bldg, University of Oxford, Off Roosevelt Drive, Oxford OX3 7DQ, United Kingdom.
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147
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Lee D, Kim T, Lim DS. The Er71 is an important regulator of hematopoietic stem cells in adult mice. Stem Cells 2011; 29:539-48. [PMID: 21425416 DOI: 10.1002/stem.597] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Ets transcription factor Er71 is an important regulator of endothelial and hematopoietic development during mammalian embryogenesis. However, the role of Er71 in adult hematopoiesis has remained unknown. We now first show that conditional deletion of Er71 in the hematopoietic system of adult mice results in a marked reduction (55%) in the number of hematopoietic stem cells (HSCs) that is likely due to increased cell death. Bone marrow transplantation (BMT) experiments further confirmed that Er71 is required for repopulation of HSCs. In addition, Er71(+/-) mice exhibited a slight decrease (37%) in the number of HSCs than those of Er71(+/+) mice, indicating that the function of Er71 in HSC maintenance is dependent on gene dosage. Moreover, Er71 was shown to be required for Tie2 expression, which contributes to HSC maintenance. Our results thus suggest the role of a single transcription factor in controlling HSCs through regulation of Tie2 expression in adult animals.
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Affiliation(s)
- Dongjun Lee
- National Creative Research Initiatives Center, Department of Biological Sciences, Graduate School of Nanoscience and Technology (WCU), Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea
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148
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Deimling SJ, Drysdale TA. Fgf is required to regulate anterior-posterior patterning in the Xenopus lateral plate mesoderm. Mech Dev 2011; 128:327-41. [PMID: 21763769 DOI: 10.1016/j.mod.2011.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 06/21/2011] [Accepted: 06/23/2011] [Indexed: 11/26/2022]
Abstract
Given that the lateral plate mesoderm (LPM) gives rise to the cardiovascular system, identifying the cascade of signalling events that subdivides the LPM into distinct regions during development is an important question. Retinoic acid (RA) is known to be necessary for establishing the expression boundaries of important transcription factors that demarcate distinct regions along the anterior posterior axis of the LPM. Here, we demonstrate that fibroblast growth factor (Fgf) signalling is also necessary for regulating the expression domains of the same transcription factors (nkx2.5, foxf1, hand1 and sall3) by restricting the RA responsive LPM domains. When Fgf signalling is inhibited in neurula stage embryos, the more posterior LPM expression domains are lost, while the more anterior domains are extended further posterior. The domain changes are maintained throughout development as Fgf inhibition results in similar domain changes in late stage embryos. We also demonstrate that Fgf signalling is necessary for both the initiation of heart specification, and for maintaining heart specification until overt differentiation occurs. Fgf signalling is also necessary to restrict vascular patterning and create a vascular free domain in the posterior end of the LPM that correlates with the expression of hand1. Finally, we show cross talk between the RA and Fgf signalling pathways in the patterning of the LPM. We suggest that this tissue wide patterning event, active during the neurula stage, is an initial step in regional specification of the LPM, and this process is an essential early event in LPM patterning.
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Affiliation(s)
- Steven J Deimling
- Children's Health Research Institute, 800 Commissioners Road E., London, Ontario, Canada
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149
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DeLaughter DM, Saint-Jean L, Baldwin HS, Barnett JV. What chick and mouse models have taught us about the role of the endocardium in congenital heart disease. ACTA ACUST UNITED AC 2011; 91:511-25. [PMID: 21538818 DOI: 10.1002/bdra.20809] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/08/2011] [Accepted: 02/17/2011] [Indexed: 12/16/2022]
Abstract
Specific cell and tissue interactions drive the formation and function of the vertebrate cardiovascular system. Although much attention has been focused on the muscular components of the developing heart, the endocardium plays a key role in the formation of a functioning heart. Endocardial cells exhibit heterogeneity that allows them to participate in events such as the formation of the valves, septation of the outflow tract, and trabeculation. Here we review, the contributions of the endocardium to cardiovascular development and outline useful approaches developed in the chick and mouse that have revealed endocardial cell heterogeneity, the signaling molecules that direct endocardial cell behavior, and how these insights have contributed to our understanding of cardiovascular development and disease.
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Affiliation(s)
- Daniel M DeLaughter
- Departments of Cell & Developmental Biology, Vanderbilt University Medical Center, 2220 Pierce Ave., Nashville, TN 37232-6600, USA
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Kamei CN, Kempf H, Yelin R, Daoud G, James RG, Lassar AB, Tabin CJ, Schultheiss TM. Promotion of avian endothelial cell differentiation by GATA transcription factors. Dev Biol 2011; 353:29-37. [PMID: 21354132 DOI: 10.1016/j.ydbio.2011.02.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 02/14/2011] [Accepted: 02/15/2011] [Indexed: 11/30/2022]
Abstract
In the avian embryo, endothelial cells originate from several sources, including the lateral plate and somite mesoderm. In this study, we show that Gata transcription factors are expressed in the lateral plate and in vasculogenic regions of the avian somite and are able to promote a vascular endothelial fate when ectopically expressed in somite precursors. A fusion of GATA4 to the transcriptional activator VP16 promoted endothelium formation, indicating that GATA transcription factors promote vasculogenesis via activation of downstream targets, while a fusion of GATA4 to the transcriptional repressor engrailed repressed expression of Vascular Endothelial Growth Factor Receptor 2, a marker of endothelial precursors. These findings indicate a role for GATA transcription factors in the differentiation of the endothelium.
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Affiliation(s)
- Caramai N Kamei
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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