title: Impact of vegf on astrocytes: analysis of gap junctional intercellular communication, proliferation, and motility.
abstract: The purpose of the present study was to investigate the effects of vascular endothelial growth factor (VEGF) on gap junctional intercellular communication (GJIC), cell proliferation, and cell dynamics in primary astrocytes. VEGF is known as a dimeric polypeptide that potentially binds to two receptors, VEGFR-1 and VEGFR-2, however many effects are mediated by VEGFR-2, for example, actin polymerization, forced cell migration, angiogenesis, and cell proliferation. Recently it has been shown that in case of hypoxia, ischemia or injury VEGF is upregulated to stimulate angiogenesis and cell proliferation. Besides this, VEGF reveals a potent therapeutical target for averting tumor vascularization, emerging in bevacizumab, the first humanized anti-VEGF-A antibody for treating recurrent Glioblastoma multiforme. To expand our knowledge about VEGF effects in glial cells, we cultivated rat astrocytes in medium containing VEGF for 1 and 2 days. To investigate the effects of VEGF on GJIC, we microinjected neurobiotin into a single cell and monitored dye-spreading into adjacent cells. These experiments showed that VEGF significantly enhances astrocytic GJIC compared with controls. Cell proliferation measured by BrdU-labeling also revealed a significant increase of astrocytic mitose rates subsequent to 1 day of VEGF exposure, whereas longer VEGF treatment for 2 days did not have additive effects. To study cell-dynamics of astrocytes subsequent to VEGF treatment, we additionally transfected astrocytes with LifeAct-RFP. Live-cell imaging and quantitative analysis of these cells with aid of confocal laser scanning microscopy revealed higher process movement of VEGF-treated astrocytes. In conclusion, VEGF strongly affects cell proliferation, GJIC, and motility in astrocytes.
authors.affiliation: Institute of Anatomy and Molecular Embryology, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Ricarda
authors.initials: R
authors.lastname: Wuestefeld
authors.forename: Jingchen
authors.initials: J
authors.lastname: Chen
authors.forename: Karl
authors.initials: K
authors.lastname: Meller
authors.forename: Beate
authors.initials: B
authors.lastname: Brand-Saberi
authors.forename: Carsten
authors.initials: C
authors.lastname: Theiss
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism* / Q000648:ultrastructure; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D000075302:Connexin 30; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism; D017630:Connexins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D053331:Ectodysplasins / Q000378:metabolism; D004622:Embryo, Mammalian; D017629:Gap Junctions / Q000378:metabolism* / Q000648:ultrastructure; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D008845:Microinjections; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
chemical_list: D039481:CD11b Antigen; D000075302:Connexin 30; D018031:Connexin 43; D017630:Connexins; D053331:Ectodysplasins; C508770:Gjb6 protein, rat; D005904:Glial Fibrillary Acidic Protein; D042461:Vascular Endothelial Growth Factor A; C070614:neurobiotin; D001710:Biotin; D001973:Bromodeoxyuridine