Kojima Hideyuki, Nies Anne T, König Jörg, Hagmann Wolfgang, Spring Herbert, Uemura Masahito, Fukui Hiroshi, Keppler Dietrich
Division of Tumor Biochemistry, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
J Hepatol. 2003 Nov;39(5):693-702. doi: 10.1016/s0168-8278(03)00410-0.
BACKGROUND/AIMS: Expression and localization of human hepatocellular transporters and of radixin, cross-linking actin with some membrane transporters, may change in cholestatic liver diseases.
We investigated the uptake transporters OATP2 (SLC21A6), OATP8 (SLC21A8), and NTCP (SLC10A1), the export pumps MRP2 (ABCC2), MRP3 (ABCC3), MRP6 (ABCC6), and P-glycoproteins (ABCB1, ABCB4, ABCB11), and radixin, in non-icteric primary biliary cirrhosis (PBC stages I-III) and control human liver needle-biopsies using immunofluorescence microscopy and semi-quantitative RT-PCR.
Expression and localization of all transporters were unchanged in PBC I-II. Immunostaining intensities of uptake transporters decreased in PBC III with a concomitant decrease in mRNA levels. Immunostaining intensities and mRNA levels of export pumps were similar in controls and PBC I-III, however, irregular MRP2 immunostaining suggested redistribution of MRP2 into intracellular structures in PBC III. Areas of irregular MRP2 immunostaining showed largely reduced radixin immunostaining, whereas normal hepatocytes had MRP2 and radixin confined to the canalicular membrane. Disrupted localization of radixin and MRP2 supports the concept that radixin contributes to the canalicular localization of MRP2.
Down-regulation of uptake transporters may contribute to the impaired hepatobiliary elimination in advanced PBC, and partially altered localization of MRP2 may reflect the onset of changes leading to icteric PBC.
背景/目的：在胆汁淤积性肝病中，人肝细胞转运体以及与某些膜转运体交联肌动蛋白的根蛋白的表达和定位可能会发生变化。
我们使用免疫荧光显微镜和半定量逆转录聚合酶链反应，研究了非黄疸性原发性胆汁性肝硬化（PBC I - III期）和对照人肝穿刺活检组织中的摄取转运体OATP2（SLC21A6）、OATP8（SLC21A8）和NTCP（SLC10A1）、外排泵MRP2（ABCC2）、MRP3（ABCC3）、MRP6（ABCC6）和P - 糖蛋白（ABCB1、ABCB4、ABCB11）以及根蛋白。
在PBC I - II期，所有转运体的表达和定位均未改变。在PBC III期，摄取转运体的免疫染色强度降低，同时mRNA水平也随之下降。对照和PBC I - III期外排泵的免疫染色强度和mRNA水平相似，然而，MRP2的不规则免疫染色表明在PBC III期MRP2重新分布到细胞内结构中。MRP2免疫染色不规则的区域显示根蛋白免疫染色大大减少，而正常肝细胞中MRP2和根蛋白局限于胆小管膜。根蛋白和MRP2定位的破坏支持了根蛋白有助于MRP2在胆小管定位的概念。
摄取转运体的下调可能导致晚期PBC中肝胆清除功能受损，MRP2定位的部分改变可能反映了导致黄疸性PBC变化的开始。
