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。通过对mRp1基因敲除小鼠和野生型小鼠大脑皮质微量注射17β雌二醇葡萄糖醛酸的外流转运速率的比较，提示mRp1在17β雌二醇跨血脑屏障外流转运中起主要作用。此外，OAT3和Oatp3等多特异性有机阴离子转运体在脑毛细血管中表达，并定位于腔膜。在血液脑脊液中，Oat3和Oatp3位于脉络膜上皮细胞的刷状缘膜上，它们分别负责亲水性和两亲性有机阴离子的摄取。头孢克洛--一种β-内酰胺类抗生素Display…的吸收特性更多的是脉络丛存在额外的摄取机制。这些有机阴离子转运体为脑毛细血管和脉络丛提供屏障功能，并使包括药物在内的异物在脑内的浓度与其血液浓度相比相对较低。特别是对于药物，这些转运体通过将药物挤出血液循环来防止中枢神经系统药物在大脑中达到临床上显著的浓度。除了药物转运体外，我们还成功地鉴定了Oatp14作为甲状腺激素(T4)的候选转运体。据推测，它在向中枢神经系统供应血液T4方面起着重要作用。利用分子动力学自动构象分析程序(CAMDAS)和基于分子中官能团物理性质的分子叠加程序研究大鼠OAT3配体的结合构象，以寻找与配体三维结构相关的大鼠OAT3底物专一性因素。最终得到了OAT3的一种结合构象。尽管OAT3具有广泛的底物特异性，但OAT3对底物的识别可以用一个模型来描述。较少

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