MRP2 is an efflux transporter that is expressed mainly in the canalicular membrane of hepatocytes, where it expels polar and ionic compounds into the bile. MRP2 is also present in the apical membrane of enterocytes and epithelial cells of proximal tubules of the kidney. Inhibition of MRP2 transport can lead to the accumulation of metabolites and other MRP2 substrates up to toxic levels in these cells. The transport properties of MRP2 are frequently studied with the vesicular transport assay. The assay identifies compounds that interact with MRP2 by measuring the effect of a compound on the transport of a radioactively labeled or fluorescent probe. We have compared the effect of eight selected test compounds (quercetin, disopyramide, paracetamol, indomethacin, diclofenac, estrone-3-sulfate, budesonide, and thioridazine) on the MRP2-mediated transport of three commonly used probes: 5(6)-carboxy-2,7-dichlorofluorescein, leukotriene C4 and estradiol-17-β-d-glucuronide (E217βG). Five of the test compounds had different probe-dependent effects on the MRP2-mediated transport, suggesting differences in the transport mechanism of the probes. Our results underline the complexity of substrate recognition by these efflux transporters and the difficulties in directly comparing results obtained with different assays, especially when different probes are used.
Graphical Abstract
Authors:
Heidi Kidron, Gloria Wissel, Nenad Manevski, Marika Häkli, Raimo A. Ketola, Moshe Finel, Marjo Yliperttula, Henri Xhaard, Arto Urtti
Publication date:
Available online 6 June 2013
Source:Current Opinion in Chemical Biology Author(s): Rita L Strack , Samie R Jaffrey Tools to study the abundance, distribution, and flux of intracellular molecules are crucial for understanding cellular signaling and physiology. Altho ... more
Publication date:
Available online 3 June 2013
Source:Current Opinion in Chemical Biology Author(s): Yuichiro Hori , Kazuya Kikuchi Protein labeling by using a protein tag and its specific fluorescent probe is increasingly becoming a useful technique for the real-time imaging of pro ... more
The average 5-year survival for colorectal cancer (CRC) is less than 10% if metastasis occurs, but can reach 90% if detected early. A new non-invasive test has been developed that measures methylation of the SDC2 gene in tissues and blood sera. This test detected 87% of all stages of colore ... more
Regular marijuana use is associated with favorable indices related to diabetic control, say investigators. They found that current marijuana users had significantly lower fasting insulin and were less likely to be insulin resistant, even after excluding patients with a diagnosis of diabetes ... more
Most children who suffer from sports-related concussions recover within a few days. However, in a small number of children, symptoms can last for a month or more. Although there have been numerous theories as to what might predict a longer recovery time, there is no definitive answer as to ... more