eEF-2 Phosphorylation Down-Regulates P-Glycoprotein Over-Expression in Rat Brain Microvessel Endothelial Cells

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• P-glycoprotein (P-gp) is a key efflux transporter in the blood-brain barrier.
• Regulation of P-gp expression is crucial for drug delivery and multidrug resistance.
• The role of glutamate and the eEF-2K pathway in P-gp regulation is not fully understood.

Purpose of the Study:

• To investigate the role of glutamate, NMDA receptors, and the eEF-2K/eEF-2 pathway in regulating P-glycoprotein expression.
• To evaluate the effect of the eEF-2K inhibitor NH125 on P-glycoprotein expression in rat brain microvessel endothelial cells (RBMECs).

Main Methods:

• Primary RBMECs were isolated from newborn Wistar rat brains.
• Cell viability was assessed using MTT assay.
• Expression levels of Mdr1a mRNA, P-glycoprotein, phospho-eEF-2, and eEF-2 were determined by RT-PCR and Western blot analysis.

Main Results:

• L-glutamate stimulation led to increased Mdr1a mRNA and P-glycoprotein expression in RBMECs.
• NH125 treatment significantly down-regulated P-glycoprotein and phospho-eEF-2 expression in glutamate-stimulated RBMECs.
• These findings suggest a role for the eEF-2K/eEF-2 pathway in modulating P-gp levels.

Conclusions:

• The eEF-2K/eEF-2 pathway plays a significant role in regulating P-glycoprotein expression in RBMECs.
• The eEF-2K inhibitor NH125 demonstrates potential as an effective agent against multidrug resistance.