H+-peptide cotransport in the human bile duct epithelium cell line SK-ChA-1
H+-peptide cotransport in the human bile duct epithelium cell line SK-ChA-1
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DOI：
10.1152/ajpgi.00534.2001
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发表时间：
2002-07-01
影响因子：
4.5
通讯作者：
Brandsch, M
中科院分区：
文献类型：
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作者：
Knütter, I;Rubio-Aliaga, I;Brandsch, M
本研究首次描述了胆管细胞中H+-肽共转运的存在。人肝外胆管癌SK-ChA-1细胞摄取[甘氨酸-1-C-14]甘氨酰肌氨酸（[C-14] Gly-Sar）被向内的H+梯度刺激7倍。运输介导的低亲和力系统的运输常数（K-t）值为1.1 mM。几个二肽，头孢羟氨苄，和δ-氨基乙酰丙酸，但不是甘氨酸和谷胱甘肽，是强抑制剂的Gly-Sar摄取。SK-ChA-1细胞在渗透膜上形成紧密的极化单层。跨上皮电阻为856 +/- 29 Ω x cm（2）。[C-14] Gly-Sar在顶侧至基底侧方向的跨上皮通量超过基底侧至顶侧通量11倍。从顶侧摄取高20倍。RT-PCR分析使用特异性引物对的尿型肽转运蛋白（PEPT 1）或肾型（PEPT 2）显示，运输系统中表达的SK-ChA-1，也在天然兔胆管的细胞是PEPT 1。免疫组化定位PEPT 1的小鼠肝外胆管的胆管细胞的顶膜。我们的结论是，哺乳动物肝外胆道上皮细胞表达的apical膜的pathogenal-type H+-肽协同转运。SK-ChA-1细胞是研究胆管细胞中肽转运的生理和临床方面的方便模型。
This study describes for the first time the presence of H+-peptide cotransport in cells of the bile duct. Uptake of [glycine-1-C-14] glycylsarcosine ([C-14] Gly-Sar) in human extrahepatic cholangiocarcinoma SK-ChA-1 cells was stimulated sevenfold by an inwardly directed H+ gradient. Transport was mediated by a low-affinity system with a transport constant (K-t) value of 1.1 mM. Several dipeptides, cefadroxil, and delta-aminolevulinic acid, but not glycine and glutathione, were strong inhibitors of Gly-Sar uptake. SK-ChA-1 cells formed tight, polarized monolayers on permeable membranes. The transepithelial electrical resistance was 856 +/- 29 Omega x cm(2). The transepithelial flux of [C-14] Gly-Sar in apical-to-basolateral direction exceeded the basolateral-to-apical flux 11-fold. Uptake was 20-fold higher from the apical side. RT-PCR analysis using primer pairs specific for the intestinal-type peptide transporter (PEPT1) or kidney-type (PEPT2) revealed that the transport system expressed in SK-ChA-1 and also in cells of the native rabbit bile duct is PEPT1. Immunohistochemistry localized PEPT1 to the apical membrane of cholangiocytes of mouse extrahepatic biliary duct. We conclude that the cells of the mammalian extrahepatic biliary tract epithelium express the intestinal-type H+-peptide cotransporter in their apical membrane. SK-ChA-1 cells represent a convenient model to study the physiological and clinical aspects of peptide transport in cholangiocytes.