Competitive inhibition of organic anion transporting polypeptide 1c1-mediated thyroxine transport by the fenamate class of nonsteroidal antiinflammatory drugs.
Competitive inhibition of organic anion transporting polypeptide 1c1-mediated thyroxine transport by the fenamate class of nonsteroidal antiinflammatory drugs.
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DOI：
10.1210/en.2008-0188
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发表时间：
2009-02
期刊：
影响因子：
4.8
通讯作者：
Daniel E. Westholm;D. Stenehjem;J. Rumbley;L. Drewes;G. Anderson
中科院分区：
文献类型：
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作者：
Daniel E. Westholm;D. Stenehjem;J. Rumbley;L. Drewes;G. Anderson
有机阴离子转运多肽（Oatp）1c1是一种高亲和力的T（4）转运蛋白，在血脑屏障上表达，具有窄的底物特异性。建立了一种使用过表达Oatp1c1的细胞的转运模型，以鉴定新的Oatp1c1底物和抑制剂。克隆大鼠Oatp1c1基因并在人胚肾293细胞中稳定表达。Oatp1c1转染的人胚肾293细胞以时间依赖性方式转运（125）I标记的T（4），在过量未标记T（4）存在时完全消失。接下来，筛选了各种化合物，包括甲状腺激素摄取抑制剂，以抑制Oatp1c1介导的T（4）摄取。当在10 μ M浓度下测定时，苯妥英（64%）、吲哚菁绿色（17%）、芬那酸（68%）、双氯芬酸（51%）和甲氯芬酸（33%）均降低Oatp1c 1对T（4）的摄取。芬那酸、碘番酸、吲哚菁绿色和苯妥英的剂量反应试验显示，Oatp1c1 T（4）摄取的IC（50）值低于或接近治疗剂量后的血浆水平。进一步的动力学分析和倒易图分析表明，芬那酸双氯芬酸以竞争方式抑制。最后，从成年大鼠脑中分离微血管并评估T（4）摄取。10微摩尔浓度的芬那酯抑制T（4）微血管摄取，具有类似的分级抑制特征[芬那酸（43%）、双氯芬酸（78%）和甲氯芬酸（85%）]，与Oatp1c1转染细胞中观察到的相似。Oatp1c1在血脑屏障内皮细胞的腔内和腔外表达，并具有双向转运能力。总之，这些数据表明，Oatp1c1运输fenamates进入，也许跨越，脑屏障细胞。
Organic anion transporting polypeptide (Oatp) 1c1 is a high-affinity T(4) transporter with narrow substrate specificity expressed at the blood-brain barrier. A transport model using cells overexpressing Oatp1c1 was created to identify novel Oatp1c1 substrates and inhibitors. Rat Oatp1c1 was cloned and stably expressed in human embryonic kidney 293 cells. Oatp1c1-transfected human embryonic kidney 293 cells transported (125)I-labeled T(4) in a time-dependent manner that was completely abolished in the presence of excess unlabeled T(4). Next, various compounds, including inhibitors of thyroid hormone uptake, were screened for inhibitory effects on Oatp1c1-mediated T(4) uptake. Phenytoin (64%), indocyanine green (17%), fenamic acid (68%), diclofenac (51%), and meclofenamic acid (33%) all reduced T(4) uptake by Oatp1c1 when assayed at concentrations of 10 microM. Dose-response assays for the fenamic acids, iopanoic acid, indocyanine green, and phenytoin revealed IC(50) values for Oatp1c1 T(4) uptake below or near the blood plasma levels after therapeutic doses. Further kinetic assays and reciprocal plot analyses demonstrated that the fenamic acid diclofenac inhibited in a competitive manner. Finally, microvessels were isolated from adult rat brain and assessed for T(4) uptake. Ten micromolar of fenamate concentrations inhibited T(4) microvessel uptake with a similar hierarchical inhibition profile [fenamic acid (43%), diclofenac (78%), and meclofenamic acid (85%)], as observed for Oatp1c1 transfected cells. Oatp1c1 is expressed luminally and abluminally in the blood-brain barrier endothelial cell, and exhibits bidirectional transport capabilities. Together, these data suggest that Oatp1c1 transports fenamates into, and perhaps across, brain barrier cells.