Specific gene expression of XXXX -binding cassette transporters and nuclear hormone receptors in rat liver parenchymal, endothelial, and Kupffer cells.

@entity27913 @entity50595 @entity33300 @entity26837 @entity9781 @entity165 @entity13507 @entity855
Hepatic @entity165 ( @entity13507 ) uptake from serum coupled to intracellular processing and biliary excretion are important features in the removal of excess @entity165 from the body. @entity855 -binding cassette (ABC) transporters play an important role in hepatic @entity165 transport. The liver consists of different cell types, and ABC transporters may exert different physiological functions dependent on the individual cell type. Therefore, in the current study, using real time PCR we compared the mRNA expression of ABC transporters and genes involved in the regulation of @entity165 metabolism in liver parenchymal, endothelial, and Kupffer cells. It appears that liver parenchymal cells contain high expression levels compared with endothelial and Kupffer cells of scavenger receptor class BI ( approximately 3-fold), peroxisome proliferator-activated receptor (PPAR)alpha and @entity9781 (8-20-fold), @entity165 7alpha-hydroxylase A1 (>100-fold), and @entity27913 /G8 ( approximately 5-fold). Liver endothelial cells show a high expression of @entity165 27-hydroxylase, liver X receptor (LXR)beta, PPARdelta, and @entity33300 , suggesting a novel specific role for these genes in endothelial cells. In Kupffer cells, the expression level of @entity50595 , @entity26837 , and in particular @entity33300 is high, leading to an @entity33300 mRNA expression level that is 70-fold higher than in parenchymal cells. It can be calculated that 51% of the total liver @entity33300 expression resides in Kupffer cells and 24% in endothelial cells, suggesting an intrahepatic-specific role for @entity33300 in Kupffer and endothelial cells. Because of a specific stimulation of @entity33300 in parenchymal cells by a high @entity165 diet, the contribution of parenchymal cells to the total liver increased from 25 to 60%. Our data indicate that for studies of the role of ABC transporters and their regulation in liver, their cellular localization should be taken into account, allowing proper interpretation of metabolic changes, which are directly related to their (intra)cellular expression level.
