Inhibition of bile acid transport across Na+/taurocholate cotransporting polypeptide (SLC10A1) and bile salt export pump (ABCB 11)-coexpressing LLC-PK1 cells by cholestasis-inducing drugs
Inhibition of bile acid transport across Na+/taurocholate cotransporting polypeptide (SLC10A1) and bile salt export pump (ABCB 11)-coexpressing LLC-PK1 cells by cholestasis-inducing drugs
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DOI：
10.1124/dmd.105.008748
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发表时间：
2006-09-01
影响因子：
3.9
通讯作者：
Sugiyama, Yuichi
中科院分区：
文献类型：
--
作者：
Mita, Sachiko;Suzuki, Hiroshi;Sugiyama, Yuichi
胆汁酸在肝细胞间的载体转运是胆汁流动的主要驱动力，胆汁酸滞留在肝脏会引起肝毒性。胆汁酸的基侧和心尖转运体被认为是导致胆汁淤积的药物的靶点。此前，我们构建了极化的LLC-PK1细胞，它既表达主要的胆汁酸摄取转运体人Na+/牛磺胆酸共转运多肽(SLC10A1)(NTCP)，又表达胆汁酸外流转运体人胆盐输出泵(ABCB 11)(BSEP)，并表明此类细胞的单层可用于表征胆汁酸的跨细胞载体转运。在目前的研究中，我们研究了诱导胆汁淤积的药物是否可以抑制胆汁酸在这些细胞中的转运。由于荧光底物允许高通量筛选方法的发展，我们研究了NTCP和BSEP对荧光胆汁酸和牛磺胆酸盐的转运。氨基荧光素标记的胆汁酸，鹅去氧胆酰甘氨酰胆碱酯荧光素和胆碱甘氨酰胆囊素荧光素都是NTCP和BSEP的底物，它们通过共表达细胞单层的基础到根尖的转运速率是载体对照的4.3~4.5倍，但比牛磺胆酸盐小。众所周知的止胆药物，利福平、利福霉素SV、格列本脲和环孢菌素A，减少了牛磺胆酸盐通过NTCP和BSEP共表达细胞单层的基础到根尖的转运和根尖的外流清除。进一步分析表明，这两种药物对NTCP和BSEP均有抑制作用。我们的研究表明，这种共表达的细胞可以提供一个有用的系统来鉴定这两个运输系统的抑制剂，包括潜在的候选药物。
Vectorial transport of bile acids across hepatocytes is a major driving force for bile flow, and bile acid retention in the liver causes hepatotoxicity. The basolateral and apical transporters for bile acids are thought to be targets of drugs that induce cholestasis. Previously, we constructed polarized LLC-PK1 cells that express both a major bile acid uptake transporter human Na+/taurocholate cotransporting polypeptide (SLC10A1) ( NTCP) and the bile acid efflux transporter human bile salt export pump ( ABCB 11) ( BSEP) and showed that monolayers of such cells can be used to characterize vectorial transcellular transport of bile acids. In the present study, we investigated whether cholestasis-inducing drugs could inhibit bile acid transport in such cells. Because fluorescent substrates allow the development of a high-throughput screening method, we examined the transport by NTCP and BSEP of fluorescent bile acids as well as taurocholate. The aminofluoresceintagged bile acids, chenodeoxycholylglycylamidofluorescein and cholylglycylamidofluorescein, were substrates of both NTCP and BSEP, and their basal-to-apical transport rates across coexpressing cell monolayers were 4.3 to 4.5 times those of the vector control, although smaller than for taurocholate. The well known cholestatic drugs, rifampicin, rifamycin SV, glibenclamide, and cyclosporin A, reduced the basal-to-apical transport and the apical efflux clearance of taurocholate across NTCP- and BSEP-coexpressing cell monolayers. Further analysis indicated that the drugs inhibited both NTCP and BSEP. Our study suggests that such coexpressing cells can provide a useful system for the identification of inhibitors of these two transport systems, including potential drug candidates.