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Puromycin selectively increases mdr1a expression in immortalized rat brain endothelial cell lines
P Demeuse1, P Fragner, C Leroy-Noury
1INSERM-U26, Unité de Neuro-Pharmaco-Nutrition, Hôpital Fernand Widal, Paris, France.
Journal of Neurochemistry
|December 17, 2003
Summary
A new in vitro model using GPNT cells demonstrates high expression of the mdr1a gene, crucial for the blood-brain barrier (BBB). This model may help study how P-glycoprotein (P-gp) expression is regulated at the BBB.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- The blood-brain barrier (BBB) regulates molecular passage into the brain.
- P-glycoprotein (P-gp), an efflux pump, is key to the BBB's function, limiting drug entry.
- The mdr1a gene encodes P-gp and is specifically expressed in the rodent BBB.
Purpose of the Study:
- To develop and characterize an in vitro model for studying mdr1a gene regulation at the BBB.
- To investigate the effect of chronic puromycin treatment on mdr1a expression in brain endothelial cells.
Main Methods:
- Primary rat brain endothelial cells and GP8.3 cells were used as controls.
- GPNT cells, derived from GP8.3 cells, were subjected to chronic puromycin treatment.
- Quantitative analysis of mdr1a and mdr1b mRNA levels, P-gp expression, and P-gp activity was performed.
Main Results:
- GPNT cells showed significantly higher mdr1a mRNA expression and P-gp activity compared to controls.
- Chronic puromycin treatment in GPNT cells led to increased mdr1a mRNA expression.
- Treatment of GP8.3 and puromycin-starved GPNT cells with puromycin selectively increased mdr1a expression.
Conclusions:
- GPNT cells represent a valuable in vitro model for investigating mdr1a gene regulation at the BBB.
- Chronic exposure to puromycin, a P-gp substrate, can induce high mdr1a expression in this model.
- This model aids in understanding P-gp's role in drug transport across the BBB.