RT Journal Article
SR Electronic
T1 Interindividual Variability in Hepatic Expression of the Multidrug Resistance-Associated Protein 2 (MRP2/ABCC2): Quantification by Liquid Chromatography/Tandem Mass Spectrometry
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 852
OP 855
DO 10.1124/dmd.111.043810
VO 40
IS 5
A1 Anand K. Deo
A1 Bhagwat Prasad
A1 Larissa Balogh
A1 Yurong Lai
A1 Jashvant D. Unadkat
YR 2012
UL http://dmd.aspetjournals.org/content/40/5/852.abstract
AB Multidrug-associated protein 2 (MRP2) is an efflux transporter that is expressed at the bile canalicular membrane. To allow in vitro to in vivo extrapolation of the contribution of MRP2 toward hepatic disposition of its substrates, data on the interindividual variability of hepatic MRP2 protein expression are required. Therefore, we quantified the expression of MRP2 in the University of Washington (UW) human liver bank (n = 51) using a modified version of a previously validated liquid chromatography/tandem mass spectrometry assay. An unlabeled (LTIIPQDPILFSGSLR) and stable isotope-labeled (LTIIPQDPILFSGSL[13C615N1]R) surrogate peptide for MRP2 were used as the calibrator and internal standard, respectively. After isolation of the membrane fraction from the liver tissue, in-solution tryptic digestion was conducted. Quality control samples created by spiking human serum albumin or pooled human liver (n = 51) matrix with three different MRP2 synthetic peptide concentrations generated error and precision values of less than 15%. As determined by the surrogate peptide, the average MRP2 expression in the UW liver bank samples was 1.54 ± 0.64 fmol/μg liver membrane protein and was found to be independent of age (7–63 years) or sex. A single nucleotide polymorphism in the promoter region (rs717620), previously thought to affect MRP2 expression, did not influence hepatic expression of MRP2. In contrast, the single nucleotide polymorphism 21214G>A (V417I; rs2273697) was associated with significantly higher hepatic MRP2 expression.