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  • DISRUPTION  (2)
  • Disease Models, Animal  (2)
  • 1
    Keywords: CELLS ; GROWTH ; BLOOD ; GENE ; MATURATION ; DISRUPTION ; EXPRESSION ANALYSIS ; TUMOR ANGIOGENESIS ; MORPHOGENESIS ; neuropilin-1
    Abstract: OBJECTIVE: To characterize the role of a vascular-expressed class 3 semaphorin (semaphorin 3G [Sema3G]). METHODS AND RESULTS: Semaphorins have been identified as axon guidance molecules. Yet, they have more recently also been characterized as attractive and repulsive regulators of angiogenesis. Through a transcriptomic screen, we identified Sema3G as a molecule of angiogenic endothelial cells. Sema3G-deficient mice are viable and exhibit no overt vascular phenotype. Yet, LacZ expression in the Sema3G locus revealed intense arterial vascular staining in the angiogenic vasculature, starting at E9.5, which was detectable throughout adolescence and downregulated in adult vasculature. Sema3G is expressed as a full-length 100-kDa secreted molecule that is processed by furin proteases to yield 95- and a 65-kDa Sema domain-containing subunits. Full-length Sema3G binds to NP2, whereas processed Sema3G binds to NP1 and NP2. Expression profiling and cellular experiments identified autocrine effects of Sema3G on endothelial cells and paracrine effects on smooth muscle cells. CONCLUSIONS: Although the mouse knockout phenotype suggests compensatory mechanisms, the experiments identify Sema3G as a primarily endothelial cell-expressed class 3 semaphorin that controls endothelial and smooth muscle cell functions in autocrine and paracrine manners, respectively.
    Type of Publication: Journal article published
    PubMed ID: 20947821
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  • 2
    Keywords: ANGIOGENESIS ; CELLS ; EXPRESSION ; GROWTH ; GROWTH-FACTOR ; BLOOD ; CELL ; ENDOTHELIAL GROWTH-FACTOR ; Germany ; GENE ; transcription ; DIFFERENTIATION ; EPITHELIA ; TRANSCRIPTION FACTOR ; INJECTION ; BIOLOGY ; MOUSE ; DISRUPTION ; inactivation ; COMPLEMENTATION ; EPITHELIAL-CELLS ; STRATEGIES ; RECEPTORS ; INSIGHTS ; VESSELS ; nude mice ; SUBSETS ; ARCHITECTURE ; LETHALITY ; MORPHOGENESIS ; targeting ; molecular ; thymus ; MOLECULAR-BASIS ; SUBSET ; ALLELE ; BLOOD-VESSELS ; gene targeting ; mesenchyme ; development ; ALLELES ; EPITHELIUM ; function ; branching ; nude mouse blastocyst complementation ; thymus development ; VASCULAR DEVELOPMENT ; vascular endothelial growth factor
    Abstract: The thymus harbors an organ-typical dense network of branching and anastomosing blood vessels. To address the molecular basis for morphogenesis of this thymus-specific vascular pattern, we have inactivated a key vascular growth factor, VEGF-A, in thymus epithelial cells (TECs). Both Vegf-A alleles were deleted in TECs by a complementation strategy termed nude mouse [mutated in the transcription factor Foxn1 (forkhead box N1)] blastocyst complementation. Injection of Foxn1(+/+) ES cells into Foxn1(nu/nu) blastocysts reconstituted a functional thymus. By dissecting thymus stromal cell subsets, we have defined, in addition to medullary TECs (mTECs) and cortical TECs (cTECs), another prominent stromal cell subset designated cortical mesenchymal cells (cMes). In chimeric thymi, mTECs and cTECs but not cMes were exclusively ES cell-derived. According to this distinct origin, the Vegf-A gene was deleted in mTECs and cTECs, whereas cMes still expressed Vegf-A. This genetic mosaic was associated with hypovascularization and disruption of the organ-typical network of vascular arcades. Thus, vascular growth factor production by TECs is required for normal thymus vascular architecture. These experiments provide insights into Foxn1-dependent and Foxn1-independent stromal cell development and demonstrate the value of this chimeric approach to analyzing gene function in thymus epithelium
    Type of Publication: Journal article published
    PubMed ID: 16027358
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  • 3
    Publication Date: 2015-04-02
    Description: The metabolism of endothelial cells during vessel sprouting remains poorly studied. Here we report that endothelial loss of CPT1A, a rate-limiting enzyme of fatty acid oxidation (FAO), causes vascular sprouting defects due to impaired proliferation, not migration, of human and murine endothelial cells. Reduction of FAO in endothelial cells did not cause energy depletion or disturb redox homeostasis, but impaired de novo nucleotide synthesis for DNA replication. Isotope labelling studies in control endothelial cells showed that fatty acid carbons substantially replenished the Krebs cycle, and were incorporated into aspartate (a nucleotide precursor), uridine monophosphate (a precursor of pyrimidine nucleoside triphosphates) and DNA. CPT1A silencing reduced these processes and depleted endothelial cell stores of aspartate and deoxyribonucleoside triphosphates. Acetate (metabolized to acetyl-CoA, thereby substituting for the depleted FAO-derived acetyl-CoA) or a nucleoside mix rescued the phenotype of CPT1A-silenced endothelial cells. Finally, CPT1 blockade inhibited pathological ocular angiogenesis in mice, suggesting a novel strategy for blocking angiogenesis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4413024/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4413024/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schoors, Sandra -- Bruning, Ulrike -- Missiaen, Rindert -- Queiroz, Karla C S -- Borgers, Gitte -- Elia, Ilaria -- Zecchin, Annalisa -- Cantelmo, Anna Rita -- Christen, Stefan -- Goveia, Jermaine -- Heggermont, Ward -- Godde, Lucica -- Vinckier, Stefan -- Van Veldhoven, Paul P -- Eelen, Guy -- Schoonjans, Luc -- Gerhardt, Holger -- Dewerchin, Mieke -- Baes, Myriam -- De Bock, Katrien -- Ghesquiere, Bart -- Lunt, Sophia Y -- Fendt, Sarah-Maria -- Carmeliet, Peter -- 269073/European Research Council/International -- England -- Nature. 2015 Apr 9;520(7546):192-7. doi: 10.1038/nature14362. Epub 2015 Apr 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, KU Leuven, B-3000 Leuven, Belgium [2] Laboratory of Angiogenesis and Neurovascular Link, Vesalius Research Center, VIB, B-3000 Leuven, Belgium. ; 1] Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncology, KU Leuven, B-3000 Leuven, Belgium [2] Laboratory of Cellular Metabolism and Metabolic Regulation, Vesalius Research Center, VIB, B-3000 Leuven, Belgium. ; Center for Molecular &Vascular Biology, Department of Cardiovascular Research, KU Leuven; Division of Clinical Cardiology, UZ Leuven, B-3000 Leuven, Belgium. ; Laboratory of Lipid Biochemistry and Protein Interactions, KU Leuven, B-3000 Leuven, Belgium. ; 1] Vascular Patterning Laboratory, Department of Oncology, KU Leuven, B-3000 Leuven, Belgium [2] Vascular Patterning Laboratory, Vesalius Research Center, VIB, B-3000 Leuven, Belgium [3] Integrative Vascular Biology Laboratory, Max Delbruck Center for Molecular Medicine, 13125 Berlin, Germany. ; Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, B-3000 Leuven, Belgium. ; 1] Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, KU Leuven, B-3000 Leuven, Belgium [2] Laboratory of Angiogenesis and Neurovascular Link, Vesalius Research Center, VIB, B-3000 Leuven, Belgium [3] Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, B-3001 Leuven, Belgium. ; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25830893" target="_blank"〉PubMed〈/a〉
    Keywords: Acetic Acid/pharmacology ; Adenosine Triphosphate/metabolism ; Animals ; Blood Vessels/cytology/drug effects/metabolism/pathology ; Carbon/*metabolism ; Carnitine O-Palmitoyltransferase/antagonists & ; inhibitors/deficiency/genetics/metabolism ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Citric Acid Cycle ; DNA/biosynthesis ; Disease Models, Animal ; Endothelial Cells/cytology/drug effects/enzymology/*metabolism ; Fatty Acids/*chemistry/*metabolism ; Gene Silencing ; Glucose/metabolism ; Human Umbilical Vein Endothelial Cells/cytology/drug effects/metabolism/pathology ; Humans ; Mice ; Neovascularization, Pathologic/drug therapy/metabolism/pathology ; Nucleotides/*biosynthesis/chemistry/pharmacology ; Oxidation-Reduction/drug effects ; Retinopathy of Prematurity/drug therapy/metabolism/pathology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2011-10-21
    Description: Angiogenesis is critical during tumour initiation and malignant progression. Different strategies aimed at blocking vascular endothelial growth factor (VEGF) and its receptors have been developed to inhibit angiogenesis in cancer patients. It has become increasingly clear that in addition to its effect on angiogenesis, other mechanisms including a direct effect of VEGF on tumour cells may account for the efficiency of VEGF-blockade therapies. Cancer stem cells (CSCs) have been described in various cancers including squamous tumours of the skin. Here we use a mouse model of skin tumours to investigate the impact of the vascular niche and VEGF signalling on controlling the stemness (the ability to self renew and differentiate) of squamous skin tumours during the early stages of tumour progression. We show that CSCs of skin papillomas are localized in a perivascular niche, in the immediate vicinity of endothelial cells. Furthermore, blocking VEGFR2 caused tumour regression not only by decreasing the microvascular density, but also by reducing CSC pool size and impairing CSC renewal properties. Conditional deletion of Vegfa in tumour epithelial cells caused tumours to regress, whereas VEGF overexpression by tumour epithelial cells accelerated tumour growth. In addition to its well-known effect on angiogenesis, VEGF affected skin tumour growth by promoting cancer stemness and symmetric CSC division, leading to CSC expansion. Moreover, deletion of neuropilin-1 (Nrp1), a VEGF co-receptor expressed in cutaneous CSCs, blocked VEGF's ability to promote cancer stemness and renewal. Our results identify a dual role for tumour-cell-derived VEGF in promoting cancer stemness: by stimulating angiogenesis in a paracrine manner, VEGF creates a perivascular niche for CSCs, and by directly affecting CSCs through Nrp1 in an autocrine loop, VEGF stimulates cancer stemness and renewal. Finally, deletion of Nrp1 in normal epidermis prevents skin tumour initiation. These results may have important implications for the prevention and treatment of skin cancers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beck, Benjamin -- Driessens, Gregory -- Goossens, Steven -- Youssef, Khalil Kass -- Kuchnio, Anna -- Caauwe, Amelie -- Sotiropoulou, Panagiota A -- Loges, Sonja -- Lapouge, Gaelle -- Candi, Aurelie -- Mascre, Guilhem -- Drogat, Benjamin -- Dekoninck, Sophie -- Haigh, Jody J -- Carmeliet, Peter -- Blanpain, Cedric -- England -- Nature. 2011 Oct 19;478(7369):399-403. doi: 10.1038/nature10525.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉IRIBHM, Universite Libre de Bruxelles, 808 route de Lennik, 1070 Brussels, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22012397" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carcinoma, Squamous Cell/*blood supply/*pathology ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Disease Models, Animal ; Epithelial Cells/cytology ; Gene Deletion ; Gene Expression Regulation, Neoplastic ; Mice ; Neoplastic Stem Cells ; Neuropilin-1/genetics/*metabolism ; *Signal Transduction ; Skin Neoplasms/*blood supply/*pathology ; Vascular Endothelial Growth Factor A/genetics/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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