Functional expression of the apical Na+-dependent bile acid transporter in large but not small rat cholangiocytes
Functional expression of the apical Na+-dependent bile acid transporter in large but not small rat cholangiocytes
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DOI：
10.1053/gast.1997.v113.pm9352879
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发表时间：
1997-11-01
期刊：
影响因子：
29.4
通讯作者：
LeSage, GD
中科院分区：
文献类型：
--
作者：
Alpini, G;Glaser, SS;LeSage, GD
背景与目的：胆汁酸与胆管细胞相互作用，导致大而不是小的胆管细胞的胆管胆汁分泌增加和胆管细胞增殖。有人提出，胆汁酸对胆管细胞起作用，必须在胆管细胞中存在一种特定的摄取机制。本研究的目的是显示胆汁酸转运蛋白在胆管细胞中的表达。方法：分离正常大、小胆管细胞或肝内胆管单位(IBDU)，用核糖核酸酶保护法检测胆汁酸转运蛋白(ABAT)和14kodalton回肠胞浆结合蛋白(IBABP)的基因表达。并对胆汁酸转运体的组织和亚细胞分布进行了研究。测定胆管细胞对[C-14]-牛磺胆酸的摄取。结果：ABAT和IBABP信使RNA均在大而不小的胆管细胞中检测到。免疫组织化学显示ABAT存在于大而不小的胆管细胞中。免疫荧光显示在大型IBDU的顶膜中有少量的免疫荧光。大而不是小的胆管细胞中存在钠离子依赖的饱和摄取牛磺胆酸。结论：这些蛋白可能介导胆汁酸从大管的管腔中摄取，导致胆小管胆汁分泌和生长的改变。
Background & Aims: Bile acids interact with cholangiocytes, resulting in cholangiocyte proliferation and increases in ductal bile secretion in large but not small cholangiocytes. It was proposed that for bile acids to exert these effects on cholangiocytes, a specific up take mechanism must be present in cholangiocytes. The aim of this study was to show the expression of a bile acid transporter in cholangiocytes. Methods: Small and large cholangiocytes or intrahepatic bile duct units (IBDUs) were isolated from normal rats, and gene expression for the apical Na+-dependent bile acid transporter (ABAT) and the 14-kilodalton ileal cytosolic binding protein (IBABP) was assessed by ribonuclease-protection assays. Tissue and subcellular distribution of bile acid transporters was also studied. [C-14]-Taurocholate uptake into cholangiocytes was determined. Results: Both ABAT and IBABP messenger RNAs were detected in large but not small cholangiocytes. By immunohistochemistry, ABAT was present in large but not small cholangiocytes. Immunofluorescence showed ABAT to be present in the apical membrane of large IBDUs. A Na+-dependent saturable up take of taurocholate was present in large but not small cholangiocytes. Conclusions: These proteins may mediate bile acid uptake from the duct lumen in large ducts, resulting in modification of canalicular bile secretion and growth.