title: Epileptiform activity induces vascular remodeling and zonula occludens 1 downregulation in organotypic hippocampal cultures: role of VEGF signaling pathways.
abstract: Recent studies suggest that blood-brain barrier (BBB) permeability contributes to epileptogenesis in symptomatic epilepsies. We have previously described angiogenesis, aberrant vascularization, and BBB alteration in drug-refractory temporal lobe epilepsy. Here, we investigated the role of vascular endothelial growth factor (VEGF) in an in vitro integrative model of vascular remodeling induced by epileptiform activity in rat organotypic hippocampal cultures. After kainate-induced seizure-like events (SLEs), we observed an overexpression of VEGF and VEGF receptor-2 (VEGFR-2) as well as receptor activation. Vascular density and branching were significantly increased, whereas zonula occludens 1 (ZO-1), a key protein of tight junctions (TJs), was downregulated. These effects were fully prevented by VEGF neutralization. Using selective inhibitors of VEGFR-2 signaling pathways, we found that phosphatidylinositol 3-kinase is involved in cell survival, protein kinase C (PKC) in vascularization, and Src in ZO-1 regulation. Recombinant VEGF reproduced the kainate-induced vascular changes. As in the kainate model, VEGFR-2 and Src were involved in ZO-1 downregulation. These results showed that VEGF/VEGFR-2 initiates the vascular remodeling induced by SLEs and pointed out the roles of PKC in vascularization and Src in TJ dysfunction, respectively. This suggests that Src pathway could be a therapeutic target for BBB protection in epilepsies.
authors.affiliation: Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5203, INSERM U661, Université Montpellier 1, 2 Montpellier, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Morin-Brureau
authors.forename: Aurore
authors.initials: A
authors.lastname: Lebrun
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Rousset
authors.forename: Laurent
authors.initials: L
authors.lastname: Fagni
authors.forename: Joël
authors.initials: J
authors.lastname: Bockaert
authors.forename: Frédéric
authors.initials: F
authors.lastname: de Bock
authors.forename: Mireille
authors.initials: M
authors.lastname: Lerner-Natoli
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D058256:Brain Waves / Q000187:drug effects / Q000502:physiology*; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007608:Kainic Acid / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009924:Organ Culture Techniques; D010750:Phosphoproteins / Q000378:metabolism*; D011419:Propidium; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013722:Teprotide / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000276:immunology / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
chemical_list: D000779:Anesthetics, Local; D000906:Antibodies; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D042461:Vascular Endothelial Growth Factor A; D062826:Zonula Occludens-1 Protein; D011419:Propidium; D013779:Tetrodotoxin; D013722:Teprotide; D007770:L-Lactate Dehydrogenase; D040301:Vascular Endothelial Growth Factor Receptor-2; D007608:Kainic Acid