Organic Anion Transporter 3 Mediates the Efflux Transport of an Amphipathic Organic Anion, Dehydroepiandrosterone Sulfate, across the Blood-Brain Barrier in Mice
Organic Anion Transporter 3 Mediates the Efflux Transport of an Amphipathic Organic Anion, Dehydroepiandrosterone Sulfate, across the Blood-Brain Barrier in Mice
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DOI：
10.1124/dmd.110.036863
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发表时间：
2011-05-01
影响因子：
3.9
通讯作者：
Sugiyama, Yuichi
中科院分区：
文献类型：
--
作者：
Miyajima, Mari;Kusuhara, Hiroyuki;Sugiyama, Yuichi
以硫酸脱氢表雄酮（DHEAS）为探针，研究了有机阴离子跨血脑屏障（BBB）的外排转运系统。在野生型小鼠和缺乏充分表征的有机阴离子转运蛋白（有机阴离子转运多肽1a 4（Oatp 1a 4）/Slco 1a 4和有机阴离子转运蛋白3（Oat 3）/Slc 22 a8）的小鼠中，在BBB处，在显微注射到大脑皮层后，DHEAS从脑中的消除被表征。丙磺舒、苄青霉素和雌酮-3-硫酸盐可完全抑制DHEAS从脑中的饱和流出，牛磺胆酸盐和对氨基马尿酸盐可中度抑制DHEAS（50-57%）。DHEAS和雌酮-3-硫酸酯的摄取在小鼠Oat 3 cRNA注射的卵母细胞中比在水注射的卵母细胞中更大。与野生型小鼠相比，Oat 3（-/-）小鼠中这些化合物从脑中的流出显著延迟，表明Oat 3在体内确实具有重要的功能。此外，丙磺舒和牛磺胆酸盐完全抑制Oat 3（-/-）小鼠的DHEAS流出。与过去在大鼠中提示Oatp 1a 4参与的报告相反，在体外未检测到小鼠Oatp 1a 4对DHEAS和雌酮-3-硫酸酯的特异性摄取，并且在Oatp 1a 4（-/-）小鼠中，这两种化合物从脑中的流出未发生改变。从野生型、Oatp 1a 4（-/-）和Oat 3（-/-）小鼠制备的脑切片对DHEAS的摄取没有显著差异。总之，这些结果表明，Oat 3在小鼠中类固醇缀合物穿过BBB的流出中起着重要作用，并且BBB还表达用于DHEAS流出的其他未知有机阴离子转运蛋白。有机阴离子在血脑屏障的运输机制远比他们被认为是多样化的。
The present study investigated the efflux transport systems of organic anions across the blood-brain barrier (BBB) using dehydroepiandrosterone sulfate (DHEAS) as a probe. The elimination of DHEAS from the brain after microinjection into the cerebral cortex was characterized in wild-type mice and mice with deficiency of well characterized organic anion transporters, organic anion-transporting polypeptide 1a4 (Oatp1a4)/Slco1a4 and organic anion transporter 3 (Oat3)/Slc22a8, at the BBB. The saturable efflux of DHEAS from the brain was completely inhibited by probenecid, benzylpenicillin, and estrone-3-sulfate and moderately inhibited by taurocholate and p-aminohippurate (50-57%). Uptake of DHEAS and estrone-3-sulfate was greater in murine Oat3 cRNA-injected oocytes than that in water-injected oocytes. Efflux of these compounds from the brain was significantly delayed in Oat3(-/-) mice compared with that in wild-type mice, indicating that indeed Oat3 is functionally important in vivo. Furthermore, probenecid and taurocholate inhibited DHEAS efflux completely in Oat3(-/-) mice. Contrary to the past report in rats that suggested involvement of Oatp1a4, specific uptake of DHEAS and estrone-3-sulfate by murine Oatp1a4 was not detected in vitro, and efflux of both compounds from the brain was not altered in Oatp1a4(-/-) mice. There was no significant difference in the uptake of DHEAS by brain slices prepared from wild-type, Oatp1a4(-/-), and Oat3(-/-) mice. Taken together, these results suggest that Oat3 plays a significant role in the efflux of steroid conjugates across the BBB in mice and that the BBB also expresses other unknown organic anion transporters for the efflux of DHEAS. Transport mechanisms of organic anions at the BBB are far more diverse than they were assumed to be.