Previous work in our laboratory indicates that the diameter of brain arteries and arterioles can be increased by N-methyl-D-aspartate (NMDA) receptor activation. We looked for expression of NMDA receptors and endothelial cell responses to NMDA receptor agonists and antagonists in the mouse brain endothelial cell line bEnd.3. Using RT-PCR and Western blotting we found evidence supporting the presence of NMDA receptor subunits NR1 and NR2C. Treatment of bEnd.3 cells with combinations of 100 μM glutamate and D-serine significantly increased intracellular calcium. However, we saw no direct evidence that NO was produced in response to NMDA receptor activation using the Griess method. We did observe an NMDA receptor-dependent increase in protein nitrosylation. This increase is unlikely related to enhanced NO levels since it was not correlated with NO production and was not inhibited by the endothelial NO synthase inhibitor L-NIO.

Previous work in our laboratory indicates that the diameter of brain arteries and arterioles can be increased by N-methyl-D-aspartate (NMDA) receptor activation. We looked for expression of NMDA receptors and endothelial cell responses to NMDA receptor agonists and antagonists in the mouse brain endothelial cell line bEnd.3. Using RT-PCR and Western blotting we found evidence supporting the presence of NMDA receptor subunits NR1 and NR2C. Treatment of bEnd.3 cells with combinations of 100 μM glutamate and D-serine significantly increased intracellular calcium. However, we saw no direct evidence that NO was produced in response to NMDA receptor activation using the Griess method. We did observe an NMDA receptor-dependent increase in protein nitrosylation. This increase is unlikely related to enhanced NO levels since it was not correlated with NO production and was not inhibited by the endothelial NO synthase inhibitor L-NIO.

La barrière hémato-encéphalique (BHE) est une structure retrouvée au niveau des capillaires cérébraux. Elle représente un véritable obstacle pour les actifs qui doivent se rendre au cerveau pour y exercer un effet pharmacologique. Durant les étapes du développement du médicament, des modèles cellulaires in vitro sont utilisés pour l’évaluation de la perméabilité au cerveau des nouveaux médicaments. Le modèle assemblé avec des cellules endothéliales (CEs) isolées des capillaires des cerveaux de souris présente un intérêt particulier pour la recherche en raison de sa facilité d’obtention et sa pertinence pour le criblage des médicaments. Le but de ce projet a été de construire et de caractériser un modèle monocouche de CEs primaires de souris. En parallèle, un modèle monocouche de la lignée murine b.End3 a été investigué. L’évaluation de ces modèles a été basée sur les valeurs de TEER et de perméabilité aux marqueurs fluorescents, ainsi que sur la présence des protéines spécifiques de la BHE. La validation du modèle a été établie par la corrélation des résultats de perméabilité obtenus avec le modèle développé (in vitro) avec ceux obtenus chez la souris (in vivo). L’intégrité et l’expression des protéines spécifiques de la BHE du modèle primaire se sont montrées supérieures au modèle bEnd.3. La corrélation in vitro/in vivo du modèle primaire a abouti à un r2 = 0,765 comparé au r2 = 0,019 pour le modèle bEnd.3. Ce travail de recherche montre que le modèle primaire monocouche issu de cellules endothéliales cérébrales de souris est un modèle simple et fiable pour la prédiction de la perméabilité des actifs à travers la BHE. / The blood-brain barrier (BBB), a central nervous system structure, is found in the cerebral capillaries. It represents a major obstacle for the drugs that have to reach the brain in order to exercise their pharmacological effect. In the early stages of the drug development, in vitro cell models are used to evaluate the brain permeability of new drugs. Models assembled using primary endothelial cells (ECs) isolated from mouse brain capillaries are of particular interest for research, as for their ease of obtaining and relevance for the drug screening. Thus, the goal of this project was to build and characterize a primary mouse monolayer model. At the same time, a murine b.End3 cell line monolayer model was investigated. The evaluation of these models was based on the TEER and fluorescent marker permeability values, as well as on the presence of the BBB hallmark proteins. The model validation was established by the correlation of the permeability data obtained with the in vitro model and the data obtained in mice (in vivo). As a result, the primary mouse model showed superior monolayer integrity and higher expression of the tight junction and membrane transporter proteins when compared with the bEnd.3 cell line model. The in vitro/in vivo correlation of the primary model resulted in r2 = 0.765 compared to the bEnd.3 model with r2 = 0.019. This research work shows that the primary monolayer mouse model is a simple and reliable model for predicting the drug permeability across the BBB.