TY - JOUR
T1 - H+-peptide cotransport in the human bile duct epithelium cell line SK-ChA-1
AU - Knütter, Ilka
AU - Rubio-Aliaga, Isabel
AU - Boll, Michael
AU - Hause, Gerd
AU - Daniel, Hannelore
AU - Neubert, Klaus
AU - Brandsch, Matthias
PY - 2002
Y1 - 2002
N2 - This study describes for the first time the presence of H+-peptide cotransport in cells of the bile duct. Uptake of [glycine-1-14C]glycylsarcosine ([14C]Gly-Sar) in human extrahepatic cholangiocarcinoma SK-ChA-1 cells was stimulated seven-fold by an inwardly directed H+ gradient. Transport was mediated by a low-affinity system with a transport constant (Kt) value of 1.1 mM. Several dipeptides, cefadroxil, and δ-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 Ω x cm2. The transepithelial flux of [14C]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 co- transporter in their apical membrane. SK-ChA-1 cells represent a convenient model to study the physiological and clinical aspects of peptide transport in cholangiocytes.
AB - This study describes for the first time the presence of H+-peptide cotransport in cells of the bile duct. Uptake of [glycine-1-14C]glycylsarcosine ([14C]Gly-Sar) in human extrahepatic cholangiocarcinoma SK-ChA-1 cells was stimulated seven-fold by an inwardly directed H+ gradient. Transport was mediated by a low-affinity system with a transport constant (Kt) value of 1.1 mM. Several dipeptides, cefadroxil, and δ-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 Ω x cm2. The transepithelial flux of [14C]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 co- transporter in their apical membrane. SK-ChA-1 cells represent a convenient model to study the physiological and clinical aspects of peptide transport in cholangiocytes.
KW - Cell culture
KW - Membrane transport
KW - Peptide symporter
KW - Peptide transporter-1
UR - http://www.scopus.com/inward/record.url?scp=0036084735&partnerID=8YFLogxK
U2 - 10.1152/ajpgi.00534.2001
DO - 10.1152/ajpgi.00534.2001
M3 - Article
C2 - 12065310
AN - SCOPUS:0036084735
SN - 0193-1857
VL - 283
SP - G222-G229
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 1 46-1
ER -