Drug design based on the substrate specificity of the efflux transporters expressed in the blood-brain barrier

1.本研究旨在探讨血脑屏障中表达的外排转运蛋白的作用，以确定在中枢神经系统解毒系统中起主要作用的转运蛋白。通过比较Mrp 1基因敲除小鼠和野生型小鼠大脑皮质内注射雌二醇17 β葡萄糖醛酸苷后的外排转运率，提示Mrp 1在雌二醇17β葡萄糖醛酸苷跨血脑屏障的外排转运中起主要作用。此外，发现多特异性有机阴离子转运蛋白如Oat 3和Oatp 3在脑毛细血管中表达，它们位于近腔膜上。在血液CSF barreir中，Oat 3和Oatp 3已经在脉络膜上皮细胞的刷状缘膜上被鉴定，并且它们分别负责亲水性和两亲性有机阴离子的摄取。β-内酰胺类抗生素头孢克洛的吸收特性 关于我们 d在脉络丛中存在额外的摄取机制。这些有机阴离子转运蛋白为脑毛细血管和脉络丛提供屏障功能，并保持异生物质（包括药物）的脑浓度与其血液浓度相比相对较低。特别是对于药物，这些转运蛋白通过将药物挤出到血液循环中来防止CNS药物在脑中达到临床显著浓度。除了药物转运蛋白外，我们还成功地将Oatp 14表征为甲状腺素（T4）的候选转运蛋白。推测它在向中枢神经系统供应血液T4中起重要作用。利用分子动力学自动化构象分析程序（CAMDAS）和基于分子中功能基团物理性质的分子叠加程序（SUPERPOSE）研究大鼠Oat 3配体的结合构象，寻找与配体三维结构相关的大鼠Oat 3底物特异性因素。最后得到了Oat 3配体的一种结合构象。虽然Oat 3具有广泛的底物特异性，但Oat 3的底物识别可以通过一个模型来描述。少

1. The contribution of efflux transporter expressed in the blood-brain barrier was investigated in this study to identify the transporter which plays a major role in the detoxification system in the central nervous system. According to the comparison of efflux transport rate of estradiol 17β glucuronide after microinjection to the cerebral cortex in Mrp1 knockout mice and its wild-type suggested that Mrp1 plays a major role in the efflux transport of estradiol 17β glucuronide across the blood-brain barrier. In addition, it was turned out that multispecific organic anion transporters such as Oat3 and Oatp3 were expressed in the brain capillary where they localized on the abluminal membrane. In the blood CSF barreir, Oat3 and Oatp3 have been identified on the brush border membrane of the choroid epithelial cells, and they are responsible for the uptake of hydrophilic and amphipathic organic anions, respectively. Characterization of the uptake of cefaclor, a beta-lactam antibiotic reveale … More d the presence of additional uptake mechanism in the choroid plexus. These organic anion transporters provide barrier function to the brain capillary and choroid plexus, and keep the brain concentration of xenobiotics including drugs relatively low compared to their blood concentration. Especially for drugs, these transporters prevent CNS drugs reaching clinically significant concentrations in the brain by extruding drugs into the blood circulation. In addition to the drug transporters, we succeeded in characterization of Oatp14 as candidate transporter for thyroxine (T4). It is hypothesized that it plays an important role in supplying blood T4 into the central nervous system.2. The binding conformations of ligands of rat Oat3 by the automated conformational analysis program using molecular dynamics (CAMDAS) and the molecular superposing program based on the physical properties of functional groups in a molecular (SUPERPOSE) in order to search for the factors of substrate specificity of rat Oat3 in relation to three-dimensional structures of ligands. Finally, one binding conformation of ligands for Oat3 was obtained. Although Oat3 has broad substrate specificity, the substrate recognition by Oat3 can be described by one model. Less