Expression of γ-glutamyltranspeptidase in a transformed rat cerebral endothelial cell line

Caspers, Mary Lou; Diglio, Clement A.

doi:10.1016/0167-4889(84)90047-8

Cited by 32 publications

(15 citation statements)

References 18 publications

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“…Akaline phosphatase and γ-glutamyl transferase activities were measured according to the Sigma (Munich, FRG) protocol and to Caspers and Diglio [19]. Both enzymes were used as marker enzymes for the apical plasma membranes of CP epithelial cells.…”

Section: Methodsmentioning

confidence: 99%

Choroid plexus epithelial monolayers – a cell culture model from porcine brain

Baehr

Reichel

Fricker

2006

Fluids Barriers CNS

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Section: Methodsmentioning

confidence: 99%

Choroid plexus epithelial monolayers – a cell culture model from porcine brain

Baehr

Reichel

Fricker

2006

Fluids Barriers CNS

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“…g-GTP activity was measured according to the method of Casper and Diglio (1984) using glutamylp-nitroanilide (Sigma) as a substrate. The harvested cells were washed 3 times with ice-cold Hanks' balanced salt solution (Nissui) and stored at 280°C until assay.…”

Section: Assay For G-gtp Enzyme Activitymentioning

confidence: 99%

Induction of various blood‐brain barrier properties in non‐neural endothelial cells by close apposition to co‐cultured astrocytes

Hayashi¹,

Nomura²,

Yamagishi³

et al. 1997

Glia

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Vascular endothelial cells (EC) exhibit organ-to-organ heterogeneity in their functions and morphologies. In particular, brain capillary EC have unique characteristics exemplified by the blood-brain barrier (BBB). The formation and the maintenance of BBB have been ascribed to EC responses to inductive signal(s) or factor(s) from astrocytes that encircle microvessels in the central nervous system. These EC responses were demonstrated in numerous in vivo studies, exemplified by those of Janzer and Raff (Nature 325:253, 1987) and Tout et al. (Neuroscience 55:291, 1993) showing that transplanted astrocytes induced BBB properties in non-neural vascular EC. In this study, we constructed a heterologous co-culture system, in which rat fetal brain astrocytes were cultivated on one surface of a porous membrane and human umbilical vein EC on the opposite surface. Electron microscopic examination revealed that astrocytes passed their endfeet through the pores, making contact with EC. In this system, gamma-glutamyltranspeptidase (gamma-GTP) activity in EC was found to be significantly increased by contacting astrocytes in a density- and time-dependent manner, but not when the astrocyte feeder layer was apart from EC or replaced by COS cells; astrocyte-derived extracellular matrix partially activated gamma-GTP. mRNAs for some of the representative BBB markers, including transferrin receptor, P-glycoprotein, brain-type glucose transporter (GLUT-1), and gamma-GTP were also demonstrated by reverse transcription-polymerase chain reaction to be upregulated in EC co-cultured with astrocytes. Astrocyte inductions of close membrane apposition resembling a zonula occludens and of an increase in the content of mitochondria in EC were also noted in electron micrographs. Furthermore, an increased barrier activity against inulin was conferred on EC when they were lined with astrocytes. The results obtained with this heterologous co-culture system thus indicate that through contact with their feet, astrocytes are capable of transdifferentiating non-neural EC into the brain type, endowing them with the BBB properties.

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“…26) One unit of enzyme activity is deˆned as g-GTP-catalyzed formation of 1 nmol of p-nitroaniline per min at 379 Cf r o mg-glutamyl-pnitroanilide. Immunodetection of P-gp in porcine BCECs was performed as previously described with a minor modiˆcation.…”

Section: Detection Of the Bbb Markers Of Brain Capillary Endothelial mentioning

confidence: 99%

Evaluation of Blood-brain Barrier Transporters by Co-culture of Brain Capillary Endothelial Cells with Astrocytes

Kido

Tamai

Nakanishi

et al. 2002

Drug Metabolism and Pharmacokinetics

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To investigate the transport function of the blood-brain barrier (BBB), we employed an in vitro model of the BBB, consisting of a co-culture of porcine brain capillary endothelial cells (BCECs) with rat astrocytes. Porcine BCECs were cultured on a filter insert with rat astrocytes on the underlying plastic well. Rat astrocytes induced characteristic BBB properties of porcine BCECs, such as gamma-glutamyl-transpeptidase activity and intercellular adhesion of porcine BCECs. Next, the transport properties of P-glycoprotein (P-gp) substrate and several anionic compounds across the co-cultured porcine BCECs were characterized. Expression of P-gp was detected by immunocytochemistry, and efflux-directed transport of the P-gp substrate [(3)H]daunomycin was observed. Luminal-to-abluminal transport of the monocarboxylic acid transporter 1 (MCT1) substrate [(14)C]benzoic acid was saturable, and the K(m) value (3.05 mM) was similar to that for brain uptake observed in vivo. Abluminal-to-luminal transport of [(14)C]benzoic acid was also saturable, indicating that the monocarboxylic acid transporter of the BBB contributes to the efflux from the brain as well as to blood-to-brain influx. Abluminal-to-luminal transport of organic anions, [(3)H]dehydroepiandrosterone sulfate, [(3)H]estrone sulfate and [(3)H]estradiol 17beta-D-glucuronide was significantly higher than the corresponding luminal-to-abluminal transport. These results demonstrate the presence of multiple efflux transport pathways in this in vitro model.

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Expression of γ-glutamyltranspeptidase in a transformed rat cerebral endothelial cell line

Cited by 32 publications

References 18 publications

Choroid plexus epithelial monolayers – a cell culture model from porcine brain

Choroid plexus epithelial monolayers – a cell culture model from porcine brain

Induction of various blood‐brain barrier properties in non‐neural endothelial cells by close apposition to co‐cultured astrocytes

Evaluation of Blood-brain Barrier Transporters by Co-culture of Brain Capillary Endothelial Cells with Astrocytes

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