Regulation of choline transport by oxidative stress at the blood-brain barrier in vitro model

Abstract

In the present study, we examined how the transport of choline is regulated at the blood-brain barrier (BBB) under the central nervous system (CNS) cellular damages by oxidative stress using a conditionally immortalized rat brain capillary endothelial cells (TR-BBB), in vitro the BBB model. It was also tested whether the choline uptake is influenced by membrane potential, extracellular pH, protonophore (FCCP) and amiloride in TR-BBB cells. In result, [H-3]choline uptake was inhibited by FCCP and dependent on extracellular pH. The treatment of TR-BBB cells with 20 ng/mL tumor necrosis factor-alpha (TNF-alpha), 10 ng/mL lipopolysaccharide (LPS), 100 mu M diethyl maleate (DEM) and 100 mu M glutamate resulted in 3.0-fold, 2.6-fold, 1.8-fold and 2.0-fold increases of [H-3]choline uptake at the respective peak time, respectively. In contrast, hydrogen peroxide and raffinose did not show any significant effects on choline uptake. In addition, choline efflux was significantly inhibited by TNF-alpha, LPS and DEM producing cell damage states. In conclusion, the influx and efflux transport system for choline existed in TR-BBB cell line and this process was affected by several oxidative stress inducing agents.