P-glycoprotein expression in rat brain endothelial cells: evidence for regulation by transient oxidative stress
P-glycoprotein expression in rat brain endothelial cells: evidence for regulation by transient oxidative stress
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DOI：
10.1046/j.0022-3042.2001.00660.x
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发表时间：
2002-01-01
影响因子：
4.7
通讯作者：
Barrand, MA
中科院分区：
文献类型：
--
作者：
Felix, RA;Barrand, MA
在缺血/再灌流期间，血脑屏障的细胞受到氧化应激的影响。本研究使用原代培养的大鼠脑内皮细胞来检测这种应激对多药转运蛋白表达的影响。H_2O_2作用于细胞单层后，P-糖蛋白(Pgp)的表达呈浓度依赖性增加，而多药耐药相关蛋白(MRP_1)的表达无明显变化。浓度为250微米的H_2O_2会降低细胞存活率。从[H-3]长春新碱蓄积实验来看，100um H_2O_2处理48h后，PGP功能活性显著增加。在此浓度下，H_2O_2在10分钟内产生一过性增加，随后细胞内活性氧(IROS)水平持续下降，这可通过流式细胞仪检测到。缺氧6h后单层细胞复氧可引起IROS表达增加，24 h后Pgp表达增加，4h内mdr1a和mdr1b基因表达均升高。有证据表明，这是由于转录增强而不是mRNA稳定所致。因此，氧化应激通过改变Pgp的表达，可能影响Pgp底物进出大脑的运动。
During ischaemia/reperfusion, cells of the blood-brain barrier are subjected to oxidative stress. This study uses primary cultured rat brain endothelial cells to examine the effect of such stresses on expression of multidrug transporters. H2O2 up to 500 muM applied to cell monolayers caused a concentration-dependent increase in expression of P-glycoprotein (Pgp) but not of multidrug resistance-associated protein (Mrp1). Concentrations >250 muM H2O2 decreased cell viability. Application of 100 muM H2O2 caused a significant increase after 48 h in Pgp functional activity, as assessed from [H-3]vincristine accumulation experiments. At this concentration, H2O2 produced a transient increase within 10 min followed by a sustained decrease in levels of intracellular reactive oxygen species (iROS), detectable by flow cytometry. Reoxygenation of cell monolayers after 6 h hypoxia gave rise to a similar transient increase in iROS and this also led to increased Pgp expression by 24 h. Increases were also observed within 4 h after both H2O2 and hypoxia/reoxygenation treatments in mdr1a and mdr1b mRNA. Evidence suggests this was due to enhanced transcription rather than mRNA stabilization. Therefore, oxidative stress, by changing Pgp expression, may affect movement of Pgp substrates in and out of the brain.