Development of new drug screening system using the blood-brain barrier transporter gene expression

血脑屏障转运的体外筛选系统是开发中枢神经系统作用药物的重要课题。建立了脑毛细血管内皮细胞、星形胶质细胞、周细胞、脉络丛上皮细胞、视网膜内皮细胞、骨髓源性内皮细胞等条件永生化细胞系。其中，脑毛细血管内皮细胞系表达P-糖蛋白、己糖转运蛋白和有机阴离子转运蛋白。利用这些细胞系，我们揭示了血脑屏障转运蛋白基因。我们发现，ATA 2是系统A的负责基因，位于脑毛细血管内皮细胞的近腔膜。高渗条件可诱导ATA 2的mRNA表达和转运功能。我们还发现，TAUT是负责牛磺酸的血脑屏障转运。高渗介质和细胞因子可诱导TAUT，牛磺酸过冷可降低TAUT。我们还阐明了有机阴离子转运蛋白3（OAT 3）在大鼠血脑屏障上转运硫酸吲哚酚（一种尿毒症毒素）和硫酸脱氢表雄酮。此外，我们还揭示了Rot是rOAT 3的小鼠计数器部分。我们还发现血脑屏障CRT在循环血中肌酸的摄取到脑中起重要作用。这些发现将对开发中枢神经系统作用的新药非常有用。

For the development of central nervous system (CNS) acting drug, it is very important subject to have in vitro screening system of the blood-brain barrier transport. We have established the conditionally immortalized cell lines of the brain capillary endothelial cell, astrocyte, pericyte, choroid plexus epithelial cell, retinal endothelial cell, bone marrow derived endothelial cell. Among these cell lines, the brain capillary endothelial cell lines expressed the function of P-glycoprotein, hexose transporter and organic anion transporter. Employing these cell lines, we have revealed the blood-brain barrier transporter gene. We found that ATA2 is responsible gene for the system A, located at the abluminal membrane of the brain capillary endothelial cells. mRNA and transport functio of ATA2 was induced by the hypertonic condition. We have also revealed that TAUT is responsible for the blood-brain barrier transport of taurine. TAUT was induced by hyperosmotic medium condition and cytokine, and reduced by excess cold of taurine. We have also clarified that organic anion transporter 3, OAT3, transport indoxyl sulfate, an uremic toxine, and dehydroepiandrosterone sulfate at the blood-brain barrier in rats. Moreover, we have also revealed that Roct is the mouse counter part of rOAT3. We have also found that the blood-brain barrier CRT play an important role of the uptake of creatine from the circulating blood to the brain. These findings would be very useful for the development of the CNS acting new drug.