scholarly journals Regulation of the glutamate transporter by amino acid deprivation and associated effects on the level of EAAC1 mRNA in the renal epithelial cell line NBL-I

1993 ◽  
Vol 295 (3) ◽  
pp. 749-755 ◽  
Author(s):  
S Plakidou-Dymock ◽  
J D McGivan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Epithelial Cell ◽  
Cell Line ◽  
Glutamate Transport ◽  
Epithelial Cell Line ◽  
Amino Acid Deprivation ◽  
Renal Epithelial Cell ◽  
High Affinity ◽  
Renal Epithelial Cell Line

The glutamate transport system of the bovine renal epithelial cell line NBL-1 was studied. The Km for Na(+)-dependent glutamate transport was found to be 13.8 +/- 2.4 microM (Vmax. 365 +/- 19.2 pmol/3 min per mg) and for Na(+)-dependent aspartate transport 4.5 +/- 1.1 microM (Vmax. 108 +/- 6.3 pmol/3 min per mg). The Km values are in close agreement with those expected for high-affinity Na(+)-dependent glutamate transport by System XAG-. Upon deprivation of amino acids, the Vmax. for Na+/aspartate co-transport rose to 203 +/- 6.0 pmol/3 min per mg (Km 3.8 +/- 0.5 microns). A probe was constructed to the high-affinity excitatory amino acid carrier (EAAC1) [Kanai and Hediger (1992) Nature (London) 360, 467-471]. The probe hybridized to a 3.5 kb transcript. On deprivation of amino acids, the level of EAAC1 mRNA decreased sharply before the measurable increase in transport levels, but was subsequently restored to control levels. A motif, which we propose is linked to amino acid deprivation, was found in the EAAC1 primary sequence.

scholarly journals Induction of the high-affinity Na+-dependent glutamate transport system XAG- by hypertonic stress in the renal epithelial cell line NBL-1

1995 ◽  
Vol 310 (2) ◽  
pp. 689-692 ◽  
Author(s):  
A Ferrer-Martinez ◽  
A Felipe ◽  
B Nicholson ◽  
J Casado ◽  
M Pastor-Anglada ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
Transport System ◽  
Glutamate Transport ◽  
Transport Systems ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Hypertonic Stress ◽  
High Affinity ◽  
Renal Epithelial Cell Line

The high-affinity Na(+)-dependent glutamate transport system XAG- is induced (threefold increase in Vmax. with no change in Km) by hypertonicity in the renal epithelial cell line NBL-1. This effect is dependent on protein synthesis and glycosylation and is accompanied by an increase in EAAC1 mRNA levels. Other Na(+)-dependent transport systems in this cell line do not respond to hypertonic stress. In contrast to recent findings [Ruiz-Montasell, Gomez-Angelats, Casado, Felipe, McGivan and Pastor-Anglada (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 9569-9573] showing that increased system A activity after hyperosmotic shock results from induction of a regulatory protein, this is the first demonstration that hypertonicity may increase the expression of the gene for an amino acid transport protein itself.

scholarly journals Amino acid deprivation leads to the emergence of System A activity and the synthesis of a specific membrane glycoprotein in the bovine renal epithelial cell line NBL-1

1992 ◽  
Vol 284 (2) ◽  
pp. 577-582 ◽  
Author(s):  
A Felipe ◽  
C Soler ◽  
J D McGivan
Keyword(s):  
Amino Acid ◽  
Epithelial Cell ◽  
Epithelial Cell Line ◽  
Membrane Glycoprotein ◽  
Amino Acid Deprivation ◽  
Transport Activity ◽  
Renal Epithelial Cell ◽  
System A ◽  
Alanine Transport ◽  
Renal Epithelial Cell Line

1. Amino acid deprivation of confluent monolayers of the bovine renal epithelial cell line NBL-1 causes a stimulation of Na(+)-dependent alanine transport. 2. This stimulation is mediated by a protein-synthesis-dependent induction of 2-(methylamino)isobutyric acid (methyl-AIB)-sensitive alanine transport activity (System A), which was not previously present in these cells. 3. Induction was prevented by the addition of methyl-AIB, alanine or glutamine. 4. Tunicamycin prevented the induction of alanine transport activity. 5. Induction of System A activity was accompanied by incorporation of [3H]mannose into a single membrane protein band of molecular mass 113-140 kDa. 6. These results are consistent with the possibility that induced System A activity in confluent NBL-1 cells is mediated by the synthesis of a 113-140 kDa membrane glycoprotein.

Electrophysiological Measurements of a Toad Renal Epithelial Cell Line (A6) as an Assay for Predicting Ocular Eye Irritancy

1992 ◽  
Vol 20 (2) ◽  
pp. 218-221
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
South African ◽  
Mdck Cells ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Electrophysiological Measurements ◽  
Renal Epithelial Cell Line ◽  
Darby Canine Kidney

An established epithelial cell line (A6) from a South African clawed toad (Xenopus laevis) kidney was used as a model for the corneal epithelium of the eye in order to determine ocular irritancy. When grown on Millipore filter inserts, A6 cells form a monolayer epithelium of high electrical resistance and generate a trans-epithelial potential difference. These two easily-measured electrophysiological endpoints showed a dose-related decrease after exposure for 24 hours to seven selected chemicals of different ocular irritancy potential. It was demonstrated that both trans-epithelial resistance and potential ranked closely with in vivo eye irritancy data and correlated well (r = 0.96) with loss of trans-epithelial impermeability of Madin-Darby canine kidney (MDCK) cells, detected by use of a fluorescein leakage assay.

scholarly journals Expression of phosphoenolpyruvate carboxykinase (PEPCK) chimeras in renal epithelial cells. Retention of appropriate physiological responsiveness using enhancerless retroviral vectors

1992 ◽  
Vol 284 (3) ◽  
pp. 725-732 ◽  
Author(s):  
A S Pollock ◽  
D H Lovett
Keyword(s):  
Epithelial Cell ◽  
Cyclic Amp ◽  
Cell Line ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Large Fraction ◽  
Expression System ◽  
Retroviral Vectors ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Renal Epithelial Cell Line

We used an enhancerless U3 mutant retroviral vector to deliver chimeras of the phosphoenolpyruvate carboxykinase (PEPCK) promoter region to a renal epithelial cell line capable of expressing PEPCK mRNA. Chimeras consisting of the PEPCK promoter and chloramphenicol acetyltransferase, neomycin phosphotransferase or human growth hormone genes were expressed after viral infection of the NRK52E renal epithelial cell line. Virus-delivered sequences in which the direction of PEPCK promoter transcription was antegrade to the normal direction of the long terminal repeat (LTR)-initiated transcription correctly upon stimulation with dexamethasone or 8-bromo cyclic AMP and upon lowering of the extracellular pH. Fluorescent primer extension in situ using primers specific for virus-delivered sequences of antegrade constructs indicated that a large fraction of NRK52E cells could be infected by co-cultivation with virus-producing psi-2 cells without G418 selection. Virus-delivered constructs whose orientation was opposite to that of the LTRs were expressed at very low levels, with transcripts detectable by PCR only in RNA from cyclic AMP-treated cells. Using reverse transcription/PCR, we demonstrated that the chimeric transcripts were from the internal PEPCK promoter rather than a functional or reconstituted Moloney LTR. PEPCK-reporter chimeras delivered by retroviral vectors demonstrated a level of expression more consistent with the level of expression of the native PEPCK gene than did transfected chimeras. This expression system should prove useful for studies of the physiological modulation of gene expression in renal tissues.

Cytokine-induced release of endothelin-1 from porcine renal epithelial cell line

1990 ◽  
Vol 169 (2) ◽  
pp. 578-584 ◽  
Author(s):  
Kazuki Ohta ◽  
Yukio Hirata ◽  
Taihei Imai ◽  
Kazuo Kanno ◽  
Toshiaki Emori ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Endothelin 1 ◽  
Renal Epithelial Cell Line
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