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Abstract
Angiogenesis, defined as the sprouting of new blood vessels from preexisting ones, is a biological process of great clinical relevance due to its involvement in disease as well as its therapeutic potential for revascularizing ischemic tissues. The embryonic mouse hindbrain provides an excellent model to study the molecular and cellular mechanisms of angiogenesis in vivo due the simple geometry of the hindbrain vasculature and its easy accessibility for fluorescent or histochemical staining, and for image capture and quantitation. This chapter outlines protocols for dissection, staining, and analysis of the mouse embryo hindbrain vasculature.
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102
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Ferreras C, Cole CL, Urban K, Jayson GC, Avizienyte E. Segregation of late outgrowth endothelial cells into functional endothelial CD34- and progenitor-like CD34+ cell populations. Angiogenesis 2015; 18:47-68. [PMID: 25269667 DOI: 10.1007/s10456-014-9446-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 09/19/2014] [Indexed: 01/16/2023]
Abstract
Late outgrowth endothelial cells (OECs) that originate from peripheral blood mononuclear cells ex vivo have phenotypic and functional properties of mature endothelial cells. Given the potential therapeutic applications of OECs, understanding their biology is crucial. We have identified two distinct OEC populations based on differential expression of the cell surface marker CD34. OEC colonies lacked CD34 expression (CD34-), expressed CD34 in the majority of cells (CD34+), or showed a mixed expression pattern within a colony (CD34+/-). CD34+ and CD34- OECs were negative for hematopoietic cell marker CD45 and expressed the endothelial cell surface markers CD31, CD146, CD105, and VEGFR-2. Functionally CD34- and CD34+ OECs exhibited strikingly distinct behaviors. CD34- OECs, unlike CD34+ OECs, were capable of sprouting, formed tubes, and responded to angiogenic growth factors in vitro. In vivo, CD34- OECs formed endothelial tubes, while CD34+ OECs, despite being unable to form tubes, promoted infiltration of murine vasculature. Global gene expression profiling in CD34- and CD34+ OECs identified functional importance of the MMP-1/PAR-1 pathway in CD34- OECs. MMP-1 stimulated the expression of VEGFR-2, neuropilin-1, neuropilin-2, and CXCR4 and activated ERK1/2, whereas down-regulation of PAR-1 in CD34- OECs resulted in impaired angiogenic responses in vitro and reduced VEGFR-2 levels. In contrast, the CD34+ OEC colonies expressed high levels of the progenitor cell marker ALDH, which was absent in CD34- OECs. In summary, we show that OECs can be classified into functionally mature endothelial cells (CD34- OECs) that depend on the MMP-1/PAR-1 pathway and progenitor-like angiogenesis-promoting cells (CD34+ OECs).
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Affiliation(s)
- Cristina Ferreras
- Institute of Cancer Sciences, Faculty of Medical and Human Sciences, The University of Manchester, Paterson Building, Wilmslow Road, Manchester, M20 4BX, UK
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103
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Fantin A, Ruhrberg C. The Embryonic Mouse Hindbrain and Postnatal Retina as In Vivo Models to Study Angiogenesis. Methods Mol Biol 2015; 1332:177-188. [PMID: 26285754 DOI: 10.1007/978-1-4939-2917-7_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Angiogenesis, the growth of new blood vessels from preexisting ones, is a fundamental process for organ development, exercise-induced muscle growth, and wound healing, but is also associated with different diseases such as cancer and neovascular eye disease. Accordingly, elucidating the molecular and cellular mechanisms of angiogenesis has the potential to identify new therapeutic targets to stimulate new vessel formation in ischemic tissues or inhibit pathological vessel growth in disease. This chapter describes the mouse embryo hindbrain and postnatal retina as models to study physiological angiogenesis and provides detailed protocols for tissue dissection, sample staining, and analysis.
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Affiliation(s)
- Alessandro Fantin
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK,
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104
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Lu YC, Chang SH, Hafner M, Li X, Tuschl T, Elemento O, Hla T. ELAVL1 modulates transcriptome-wide miRNA binding in murine macrophages. Cell Rep 2014; 9:2330-43. [PMID: 25533351 DOI: 10.1016/j.celrep.2014.11.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 09/17/2014] [Accepted: 11/19/2014] [Indexed: 12/19/2022] Open
Abstract
Posttranscriptional gene regulation by miRNAs and RNA binding proteins (RBP) is important in development, physiology, and disease. To examine the interplay between miRNAs and the RBP ELAVL1 (HuR), we mapped miRNA binding sites at the transcriptome-wide scale in wild-type and Elavl1 knockout murine bone-marrow-derived macrophages. Proximity of ELAVL1 binding sites attenuated miRNA binding to transcripts and promoted gene expression. Transcripts that regulate angiogenesis and macrophage/endothelial crosstalk were preferentially targeted by miRNAs, suggesting that ELAVL1 promotes angiogenesis, at least in part by antagonism of miRNA function. We found that ELAVL1 antagonized binding of miR-27 to the 3' UTR of Zfp36 mRNA and alleviated miR-27-mediated suppression of the RBP ZFP36 (Tristetraprolin). Thus, the miR-27-regulated mechanism synchronizes the expression of ELAVL1 and ZFP36. This study provides a resource for systems-level interrogation of posttranscriptional gene regulation in macrophages, a key cell type in inflammation, angiogenesis, and tissue homeostasis.
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Affiliation(s)
- Yi-Chien Lu
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Sung-Hee Chang
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Markus Hafner
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Xi Li
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Thomas Tuschl
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Olivier Elemento
- Institute for Computational Biomedicine, Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Timothy Hla
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA.
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105
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Tillo M, Erskine L, Cariboni A, Fantin A, Joyce A, Denti L, Ruhrberg C. VEGF189 binds NRP1 and is sufficient for VEGF/NRP1-dependent neuronal patterning in the developing brain. Development 2014; 142:314-9. [PMID: 25519242 PMCID: PMC4302834 DOI: 10.1242/dev.115998] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The vascular endothelial growth factor (VEGFA, VEGF) regulates neurovascular patterning. Alternative splicing of the Vegfa gene gives rise to three major isoforms termed VEGF121, VEGF165 and VEGF189. VEGF165 binds the transmembrane protein neuropilin 1 (NRP1) and promotes the migration, survival and axon guidance of subsets of neurons, whereas VEGF121 cannot activate NRP1-dependent neuronal responses. By contrast, the role of VEGF189 in NRP1-mediated signalling pathways has not yet been examined. Here, we have combined expression studies and in situ ligand-binding assays with the analysis of genetically altered mice and in vitro models to demonstrate that VEGF189 can bind NRP1 and promote NRP1-dependent neuronal responses. Summary: Although VEGF165 was thought to be the sole VEGF isoform acting through neuropilin 1 (NRP1), VEGF189 also binds to and signals through NRP1 in several types of developing mouse neurons.
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Affiliation(s)
- Miguel Tillo
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Lynda Erskine
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Anna Cariboni
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK University of Milan, Department of Pharmacological and Biomolecular Sciences, Via Balzaretti 9, Milan 20133, Italy
| | - Alessandro Fantin
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Andy Joyce
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Laura Denti
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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106
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CD31+ cell transplantation promotes recovery from peripheral neuropathy. Mol Cell Neurosci 2014; 62:60-7. [DOI: 10.1016/j.mcn.2014.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/20/2014] [Accepted: 08/12/2014] [Indexed: 12/16/2022] Open
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107
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β-adrenergic receptor antagonists inhibit vasculogenesis of embryonic stem cells by downregulation of nitric oxide generation and interference with VEGF signalling. Cell Tissue Res 2014; 358:443-52. [DOI: 10.1007/s00441-014-1976-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 07/17/2014] [Indexed: 12/26/2022]
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108
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McCollum CW, Hans C, Shah S, Merchant FA, Gustafsson JÅ, Bondesson M. Embryonic exposure to sodium arsenite perturbs vascular development in zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 152:152-163. [PMID: 24768856 DOI: 10.1016/j.aquatox.2014.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/02/2014] [Accepted: 04/05/2014] [Indexed: 06/03/2023]
Abstract
Exposure to arsenic in its inorganic form, arsenite, causes adverse effects to many different organs and tissues. Here, we have investigated arsenite-induced adverse effects on vascular tissues in the model organism zebrafish, Danio rerio. Zebrafish embryos were exposed to arsenite at different exposure windows and the susceptibility to vascular tissue damage was recorded at 72hours post fertilization (hpf). Intersegmental vessel sprouting and growth was most perturbed by exposure to arsenite during the 24-48hpf window, while disruption in the condensation of the caudal vein plexus was more often observed at the 48-72hpf exposure window, reflecting when these structures develop during normal embryogenesis. The vascular growth rate was decreased by arsenite exposure, and deviated from that of control embryos at around 24-26.5hpf. We further mapped changes in expression of key regulators of angiogenesis and vasculogenesis. Downregulation of vascular endothelial growth factor receptor 1/fms-related tyrosine kinase 1 (vegfr1/flt1) expression was evident already at 24hpf, coinciding with the decreased vascular growth rate. At later time points, matrix metalloproteinase 9 (mmp9) expression was upregulated, suggesting that arsenite affects the composition of the extracellular matrix. In total, the expression of eight key factors involved in different aspects of vascularization was significantly altered by arsenic exposure. In conclusion, our results show that arsenite is a potent vascular disruptor in the developing zebrafish embryo, a finding that calls for an evaluation of arsenite as a developmental vascular toxicant in mammalian model systems.
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Affiliation(s)
- Catherine W McCollum
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
| | - Charu Hans
- Department of Computer Science, University of Houston, Houston, TX 77204, USA
| | - Shishir Shah
- Department of Computer Science, University of Houston, Houston, TX 77204, USA
| | - Fatima A Merchant
- Department of Computer Science, University of Houston, Houston, TX 77204, USA; Department of Engineering Technology, University of Houston, Houston, TX 77204, USA
| | - Jan-Åke Gustafsson
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Maria Bondesson
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
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109
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Antidepressant-induced vascular dynamics in the hippocampus of adult mouse brain. Cell Tissue Res 2014; 358:43-55. [PMID: 24962546 DOI: 10.1007/s00441-014-1933-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 05/23/2014] [Indexed: 01/17/2023]
Abstract
New neurons are continuously added to hippocampal circuitry involved with spatial learning and memory throughout life. These new neurons originate from neural stem/progenitor cells (NSPCs) in the subgranular zone (SGZ) of the dentate gyrus (DG). Recent studies indicate that vascular reconstruction is closely connected with neurogenesis, but little is known about its mechanism. We have examined vascular reconstruction in the hippocampus of adult mouse brain after the administration of the antidepressant fluoxetine, a potent inducer of hippocampal neurogenesis. The immunohistochemistry of laminin and CD31 showed that filopodia of endothelial cells sprouted from existing thick microvessels and often formed a bridge between two thick microvessels. These filopodia were frequently seen at the molecular layer and dentate hilus of the DG, the stratum lacunosum-moleculare of the CA1, and the stratum oriens of the CA3. The filopodia were exclusively localized along cellular processes of astrocytes, but such intimate association was not seen with cell bodies and processes of NSPCs. The administration of fluoxetine significantly increased vascular density by enlarging the luminal size of microvessels and eliminating the filopodia of endothelial cells in the molecular layer and dentate hilus. Treatment with fluoxetine increased the number of proliferating NSPCs in the granule cell layer and dentate hilus, and that of endothelial cells in the granule cell layer. Thus, antidepressant-induced vascular dynamics in the DG are possibly attributable to the alteration of the luminal size of microvessels rather than to proliferation of endothelial cells.
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110
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Raimondi C, Fantin A, Lampropoulou A, Denti L, Chikh A, Ruhrberg C. Imatinib inhibits VEGF-independent angiogenesis by targeting neuropilin 1-dependent ABL1 activation in endothelial cells. ACTA ACUST UNITED AC 2014; 211:1167-83. [PMID: 24863063 PMCID: PMC4042645 DOI: 10.1084/jem.20132330] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neuropilin 1 regulates angiogenesis in a VEGF-independent manner via association with ABL1, suggesting that Imatinib represents a novel opportunity for anti-angiogenic therapy. To enable new blood vessel growth, endothelial cells (ECs) express neuropilin 1 (NRP1), and NRP1 associates with the receptor tyrosine kinase VEGFR2 after binding the vascular endothelial growth factor A (VEGF) to enhance arteriogenesis. We report that NRP1 contributes to angiogenesis through a novel mechanism. In human and mouse ECs, the integrin ligand fibronectin (FN) stimulated actin remodeling and phosphorylation of the focal adhesion component paxillin (PXN) in a VEGF/VEGFR2-independent but NRP1-dependent manner. NRP1 formed a complex with ABL1 that was responsible for FN-dependent PXN activation and actin remodeling. This complex promoted EC motility in vitro and during angiogenesis on FN substrates in vivo. Accordingly, both physiological and pathological angiogenesis in the retina were inhibited by treatment with Imatinib, a small molecule inhibitor of ABL1 which is widely used to prevent the proliferation of tumor cells that express BCR-ABL fusion proteins. The finding that NRP1 regulates angiogenesis in a VEGF- and VEGFR2-independent fashion via ABL1 suggests that ABL1 inhibition provides a novel opportunity for anti-angiogenic therapy to complement VEGF or VEGFR2 blockade in eye disease or solid tumor growth.
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Affiliation(s)
- Claudio Raimondi
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK
| | - Alessandro Fantin
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK
| | | | - Laura Denti
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK
| | - Anissa Chikh
- Centre for Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary London University, London E1 2AT, England UK
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK
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111
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Koch S, van Meeteren LA, Morin E, Testini C, Weström S, Björkelund H, Le Jan S, Adler J, Berger P, Claesson-Welsh L. NRP1 presented in trans to the endothelium arrests VEGFR2 endocytosis, preventing angiogenic signaling and tumor initiation. Dev Cell 2014; 28:633-46. [PMID: 24656741 DOI: 10.1016/j.devcel.2014.02.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 11/04/2013] [Accepted: 02/13/2014] [Indexed: 11/30/2022]
Abstract
Neuropilin 1 (NRP1) modulates angiogenesis by binding vascular endothelial growth factor (VEGF) and its receptor, VEGFR2. We examined the consequences when VEGFR2 and NRP1 were expressed on the same cell (cis) or on different cells (trans). In cis, VEGF induced rapid VEGFR2/NRP1 complex formation and internalization. In trans, complex formation was delayed and phosphorylation of phospholipase Cγ (PLCγ) and extracellular regulated kinase 2 (ERK2) was prolonged, whereas ERK1 phosphorylation was reduced. Trans complex formation suppressed initiation and vascularization of NRP1-expressing mouse fibrosarcoma and melanoma. Suppression in trans required high-affinity, steady-state binding of VEGF to NRP1, which was dependent on the NRP1 C-terminal domain. Compatible with a trans effect of NRP1, quiescent vasculature in the developing retina showed continuous high NRP1 expression, whereas angiogenic sprouting occurred where NRP1 levels fluctuated between adjacent endothelial cells. Therefore, through communication in trans, NRP1 can modulate VEGFR2 signaling and suppress angiogenesis.
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Affiliation(s)
- Sina Koch
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Laurens A van Meeteren
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Eric Morin
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Chiara Testini
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Simone Weström
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | | | - Sébastien Le Jan
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Jeremy Adler
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden
| | - Philipp Berger
- Paul Scherrer Institute, Laboratory of Biomolecular Research, Molecular Cell Biology, 5232 Villigen PSI, Switzerland
| | - Lena Claesson-Welsh
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory and Science for Life Laboratory, Uppsala University, Dag Hammarskjöldsväg 20, 75185 Uppsala, Sweden.
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112
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Endothelial cells expressing low levels of CD143 (ACE) exhibit enhanced sprouting and potency in relieving tissue ischemia. Angiogenesis 2014; 17:617-30. [PMID: 24414940 DOI: 10.1007/s10456-014-9414-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 01/04/2014] [Indexed: 01/05/2023]
Abstract
The sprouting of endothelial cells from pre-existing blood vessels represents a critical event in the angiogenesis cascade. However, only a fraction of cultured or transplanted endothelial cells form new vessels. Moreover, it is unclear whether this results from a stochastic process or instead relates to certain endothelial cells having a greater angiogenic potential. This study investigated whether there exists a sub-population of cultured endothelial cells with enhanced angiogenic potency in vitro and in vivo. First, endothelial cells that participated in sprouting, and non-sprouting cells, were separately isolated from a 3D fibrin gel sprouting assay. Interestingly, the sprouting cells, when placed back into the same assay, displayed a sevenfold increase in the number of sprouts, as compared to control cells. Angiotensin-converting enzyme (CD143) was significantly down regulated on sprouting cells, as compared to regular endothelial cells. A subset of endothelial cells with low CD143 expression was then prospectively isolated from an endothelial cell culture. Finally, these cells were found to have greater potency in alleviating local ischemia, and restoring regional blood perfusion when transplanted into ischemic hindlimbs, as compared to unsorted endothelial cells. In summary, this study indicates that low expression of CD143 can be used as a biomarker to identify an endothelial cell sub-population that is more capable to drive neovascularization.
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113
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Fantin A, Herzog B, Mahmoud M, Yamaji M, Plein A, Denti L, Ruhrberg C, Zachary I. Neuropilin 1 (NRP1) hypomorphism combined with defective VEGF-A binding reveals novel roles for NRP1 in developmental and pathological angiogenesis. Development 2014; 141:556-62. [PMID: 24401374 PMCID: PMC3899814 DOI: 10.1242/dev.103028] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuropilin 1 (NRP1) is a receptor for class 3 semaphorins and vascular endothelial growth factor (VEGF) A and is essential for cardiovascular development. Biochemical evidence supports a model for NRP1 function in which VEGF binding induces complex formation between NRP1 and VEGFR2 to enhance endothelial VEGF signalling. However, the relevance of VEGF binding to NRP1 for angiogenesis in vivo has not yet been examined. We therefore generated knock-in mice expressing Nrp1 with a mutation of tyrosine (Y) 297 in the VEGF binding pocket of the NRP1 b1 domain, as this residue was previously shown to be important for high affinity VEGF binding and NRP1-VEGFR2 complex formation. Unexpectedly, this targeting strategy also severely reduced NRP1 expression and therefore generated a NRP1 hypomorph. Despite the loss of VEGF binding and attenuated NRP1 expression, homozygous Nrp1Y297A/Y297A mice were born at normal Mendelian ratios, arguing against NRP1 functioning exclusively as a VEGF164 receptor in embryonic angiogenesis. By overcoming the mid-gestation lethality of full Nrp1-null mice, homozygous Nrp1Y297A/Y297A mice revealed essential roles for NRP1 in postnatal angiogenesis and arteriogenesis in the heart and retina, pathological neovascularisation of the retina and angiogenesis-dependent tumour growth.
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Affiliation(s)
- Alessandro Fantin
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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114
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Steri V, Ellison TS, Gontarczyk AM, Weilbaecher K, Schneider JG, Edwards D, Fruttiger M, Hodivala-Dilke KM, Robinson SD. Acute depletion of endothelial β3-integrin transiently inhibits tumor growth and angiogenesis in mice. Circ Res 2014; 114:79-91. [PMID: 24103390 DOI: 10.1161/circresaha.114.301591] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 10/08/2013] [Indexed: 11/16/2022]
Abstract
RATIONALE The dramatic upregulation of αvβ3-integrin that occurs in the vasculature during tumor growth has long suggested that the endothelial expression of this molecule is an ideal target for antiangiogenic therapy to treat cancer. This discovery led to the development of small-molecule inhibitors directed against αvβ3-integrin that are currently in clinical trials. In 2002, we reported that β3-integrin-knockout mice exhibit enhanced tumor growth and angiogenesis. However, as β3-integrin is expressed by a wide variety of cells, endothelial cell-specific contributions to tumor angiogenesis are muddied by the use of a global knockout of β3-integrin function. OBJECTIVE Our aim was to examine the endothelial-specific contribution β3-integrin makes to tumor growth and angiogenesis. METHODS AND RESULTS We have crossed β3-integrin-floxed (β3-floxed) mice to 2 endothelial-specific Cre models and examined angiogenic responses in vivo, ex vivo, and in vitro. We show that acute depletion of endothelial β3-integrin inhibits tumor growth and angiogenesis preventatively, but not in already established tumors. However, the effects are transient, and long-term depletion of the molecule is ineffective. Furthermore, long-term depletion of the molecule correlates with many molecular changes, such as reduced levels of focal adhesion kinase expression and a misbalance in focal adhesion kinase phosphorylation, which may lead to a release from the inhibitory effects of decreased endothelial β3-integrin expression. CONCLUSIONS Our findings imply that timing and length of inhibition are critical factors that need to be considered when targeting the endothelial expression of β3-integrin to inhibit tumor growth and angiogenesis.
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Affiliation(s)
- Veronica Steri
- From the School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom (V.S., T.S.E., A.M.G., D.E., S.D.R.); Department of Internal Medicine, Division of Molecular Oncology, Washington University in St Louis, MO (K.W.); Luxembourg Center for Systems Biomedicine, University of Luxembourg, Luxembourg and Saarland University Medical Center, Internal Medicine II, Homburg, Germany (J.G.S.); UCL Institute of Ophthalmology, University College London, London, United Kingdom (M.F.); Barts Cancer Institute - a Cancer Research UK Centre of Excellence, Queen Mary, University of London, John Vane Science Centre, Charterhouse Square, London, United Kingdom (K.M.H.-D.)
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115
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Casazza A, Laoui D, Wenes M, Rizzolio S, Bassani N, Mambretti M, Deschoemaeker S, Van Ginderachter JA, Tamagnone L, Mazzone M. Impeding macrophage entry into hypoxic tumor areas by Sema3A/Nrp1 signaling blockade inhibits angiogenesis and restores antitumor immunity. Cancer Cell 2013; 24:695-709. [PMID: 24332039 DOI: 10.1016/j.ccr.2013.11.007] [Citation(s) in RCA: 461] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 10/04/2013] [Accepted: 11/10/2013] [Indexed: 10/25/2022]
Abstract
Recruitment of tumor-associated macrophages (TAMs) into avascular areas sustains tumor progression; however, the underlying guidance mechanisms are unknown. Here, we report that hypoxia-induced Semaphorin 3A (Sema3A) acts as an attractant for TAMs by triggering vascular endothelial growth factor receptor 1 phosphorylation through the associated holoreceptor, composed of Neuropilin-1 (Nrp1) and PlexinA1/PlexinA4. Importantly, whereas Nrp1 levels are downregulated in the hypoxic environment, Sema3A continues to regulate TAMs in an Nrp1-independent manner by eliciting PlexinA1/PlexinA4-mediated stop signals, which retain them inside the hypoxic niche. Consistently, gene deletion of Nrp1 in macrophages favors TAMs' entrapment in normoxic tumor regions, which abates their pro-angiogenic and immunosuppressive functions, hence inhibiting tumor growth and metastasis. This study shows that TAMs' heterogeneity depends on their localization, which is tightly controlled by Sema3A/Nrp1 signaling.
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Affiliation(s)
- Andrea Casazza
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium
| | - Damya Laoui
- Laboratory of Myeloid Cell Immunology, VIB, 1050 Brussels, Belgium; Laboratory of Cellular and Molecular Immunology, Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Mathias Wenes
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium
| | - Sabrina Rizzolio
- Institute for Cancer Research at Candiolo, Department of Oncology, University of Torino, 10060 Candiolo, Torino, Italy
| | - Nicklas Bassani
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium
| | - Marco Mambretti
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium
| | - Sofie Deschoemaeker
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium
| | - Jo A Van Ginderachter
- Laboratory of Myeloid Cell Immunology, VIB, 1050 Brussels, Belgium; Laboratory of Cellular and Molecular Immunology, Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Luca Tamagnone
- Institute for Cancer Research at Candiolo, Department of Oncology, University of Torino, 10060 Candiolo, Torino, Italy
| | - Massimiliano Mazzone
- Laboratory of Molecular Oncology and Angiogenesis, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, 3000 Leuven, Belgium.
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116
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Abstract
Current models of brain development support the view that VEGF, a signaling protein secreted by neuronal cells, regulates angiogenesis and neuronal development. Here we demonstrate an autonomous and pivotal role for endothelial cell-derived VEGF that has far-reaching consequences for mouse brain development. Selective deletion of Vegf from endothelial cells resulted in impaired angiogenesis and marked perturbation of cortical cytoarchitecture. Abnormal cell clusters or heterotopias were detected in the marginal zone, and disorganization of cortical cells induced several malformations, including aberrant cortical lamination. Critical events during brain development-neuronal proliferation, differentiation, and migration were significantly affected. In addition, axonal tracts in the telencephalon were severely defective in the absence of endothelial VEGF. The unique roles of endothelial VEGF cannot be compensated by neuronal VEGF and underscores the high functional significance of endothelial VEGF for cerebral cortex development and from disease perspectives.
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117
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Vempati P, Popel AS, Mac Gabhann F. Extracellular regulation of VEGF: isoforms, proteolysis, and vascular patterning. Cytokine Growth Factor Rev 2013; 25:1-19. [PMID: 24332926 DOI: 10.1016/j.cytogfr.2013.11.002] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022]
Abstract
The regulation of vascular endothelial growth factor A (VEGF) is critical to neovascularization in numerous tissues under physiological and pathological conditions. VEGF has multiple isoforms, created by alternative splicing or proteolytic cleavage, and characterized by different receptor-binding and matrix-binding properties. These isoforms are known to give rise to a spectrum of angiogenesis patterns marked by differences in branching, which has functional implications for tissues. In this review, we detail the extensive extracellular regulation of VEGF and the ability of VEGF to dictate the vascular phenotype. We explore the role of VEGF-releasing proteases and soluble carrier molecules on VEGF activity. While proteases such as MMP9 can 'release' matrix-bound VEGF and promote angiogenesis, for example as a key step in carcinogenesis, proteases can also suppress VEGF's angiogenic effects. We explore what dictates pro- or anti-angiogenic behavior. We also seek to understand the phenomenon of VEGF gradient formation. Strong VEGF gradients are thought to be due to decreased rates of diffusion from reversible matrix binding, however theoretical studies show that this scenario cannot give rise to lasting VEGF gradients in vivo. We propose that gradients are formed through degradation of sequestered VEGF. Finally, we review how different aspects of the VEGF signal, such as its concentration, gradient, matrix-binding, and NRP1-binding can differentially affect angiogenesis. We explore how this allows VEGF to regulate the formation of vascular networks across a spectrum of high to low branching densities, and from normal to pathological angiogenesis. A better understanding of the control of angiogenesis is necessary to improve upon limitations of current angiogenic therapies.
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Affiliation(s)
- Prakash Vempati
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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118
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Delalande JM, Natarajan D, Vernay B, Finlay M, Ruhrberg C, Thapar N, Burns AJ. Vascularisation is not necessary for gut colonisation by enteric neural crest cells. Dev Biol 2013; 385:220-9. [PMID: 24262984 PMCID: PMC3928993 DOI: 10.1016/j.ydbio.2013.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 11/04/2013] [Accepted: 11/08/2013] [Indexed: 12/20/2022]
Abstract
The vasculature and nervous system share striking similarities in their networked, tree-like architecture and in the way they are super-imposed in mature organs. It has previously been suggested that the intestinal microvasculature network directs the migration of enteric neural crest cells (ENCC) along the gut to promote the formation of the enteric nervous system (ENS). To investigate the inter-relationship of migrating ENCC, ENS formation and gut vascular development we combined fate-mapping of ENCC with immunolabelling and intravascular dye injection to visualise nascent blood vessel networks. We found that the enteric and vascular networks initially had very distinct patterns of development. In the foregut, ENCC migrated through areas devoid of established vascular networks. In vessel-rich areas, such as the midgut and hindgut, the distribution of migrating ENCC did not support the idea that these cells followed a pre-established vascular network. Moreover, when gut vascular development was impaired, either genetically in Vegfa(120/120) or Tie2-Cre;Nrp1(fl/-) mice or using an in vitro Wnt1-Cre;Rosa26(Yfp/+) mouse model of ENS development, ENCC still colonised the entire length of the gut, including the terminal hindgut. These results demonstrate that blood vessel networks are not necessary to guide migrating ENCC during ENS development. Conversely, in miRet(51) mice, which lack ENS in the hindgut, the vascular network in this region appeared to be normal suggesting that in early development both networks form independently of each other.
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Affiliation(s)
- Jean-Marie Delalande
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
| | - Dipa Natarajan
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
| | - Bertrand Vernay
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
| | - Malcolm Finlay
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, United Kingdom
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, United Kingdom
| | - Nikhil Thapar
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
| | - Alan J Burns
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom; Department of Clinical Genetics, The Erasmus University Medical Center, Rotterdam, The Netherlands.
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119
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Welti J, Loges S, Dimmeler S, Carmeliet P. Recent molecular discoveries in angiogenesis and antiangiogenic therapies in cancer. J Clin Invest 2013; 123:3190-200. [PMID: 23908119 DOI: 10.1172/jci70212] [Citation(s) in RCA: 456] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Four decades ago, angiogenesis was recognized as a therapeutic target for blocking cancer growth. Because of its importance, VEGF has been at the center stage of antiangiogenic therapy. Now, several years after FDA approval of an anti-VEGF antibody as the first antiangiogenic agent, many patients with cancer and ocular neovascularization have benefited from VEGF-targeted therapy; however, this anticancer strategy is challenged by insufficient efficacy, intrinsic refractoriness, and resistance. Here, we examine recent discoveries of new mechanisms underlying angiogenesis, discuss successes and challenges of current antiangiogenic therapy, and highlight emerging antiangiogenic paradigms.
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Affiliation(s)
- Jonathan Welti
- Vesalius Research Center, University of Leuven, Leuven, Belgium
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120
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The role of immune semaphorins in cancer progression. Exp Cell Res 2013; 319:1635-43. [DOI: 10.1016/j.yexcr.2013.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/24/2013] [Accepted: 04/25/2013] [Indexed: 01/13/2023]
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121
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Baer C, Squadrito ML, Iruela-Arispe ML, De Palma M. Reciprocal interactions between endothelial cells and macrophages in angiogenic vascular niches. Exp Cell Res 2013; 319:1626-34. [PMID: 23542777 DOI: 10.1016/j.yexcr.2013.03.026] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 12/12/2022]
Abstract
The ability of macrophages to promote vascular growth has been associated with the secretion and local delivery of classic proangiogenic factors (e.g., VEGF-A and proteases). More recently, a series of studies have also revealed that physical contact of macrophages with growing blood vessels coordinates vascular fusion of emerging sprouts. Interestingly, the interactions between macrophages and vascular endothelial cells (ECs) appear to be bidirectional, such that activated ECs also support the expansion and differentiation of proangiogenic macrophages from myeloid progenitors. Here, we discuss recent findings suggesting that dynamic angiogenic vascular niches might also exist in vivo, e.g. in tumors, where sprouting blood vessels and immature myeloid cells like monocytes engage in heterotypic interactions that are required for angiogenesis. Finally, we provide an account of emerging mechanisms of cell-to-cell communication that rely on secreted microvesicles, such as exosomes, which can offer a vehicle for the rapid exchange of molecules and genetic information between macrophages and ECs engaged in angiogenesis.
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Affiliation(s)
- Caroline Baer
- The Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Mario Leonardo Squadrito
- The Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - M Luisa Iruela-Arispe
- The Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland; Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute, University of California, Los Angeles 90095, CA, USA.
| | - Michele De Palma
- The Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland.
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