Protein Abundance of Drug Transporters in Human Hepatitis C Livers

Abstract

Transmembrane drug transport in hepatocytes is one of the major determinants of drug pharmacokinetics. In the present study, ABC transporters (P-gp, MRP1, MRP2, MRP3, MRP4, BCRP, and BSEP) and SLC transporters (MCT1, NTCP, OAT2, OATP1B1, OATP1B3, OATP2B1, OCT1, and OCT3) were quantified for protein abundance (LC-MS/MS) and mRNA levels (qRT-PCR) in hepatitis C virus (HCV)-infected liver samples from the Child-Pugh class A (n = 30), B (n = 21), and C (n = 7) patients. Protein levels of BSEP, MRP3, MCT1, OAT2, OATP1B3, and OCT3 were not significantly affected by HCV infection. P-gp, MRP1, BCRP, and OATP1B3 protein abundances were upregulated, whereas those of MRP2, MRP4, NTCP, OATP2B1, and OCT1 were downregulated in all HCV samples. The observed changes started to be seen in the Child-Pugh class A livers, i.e., upregulation of P-gp and MRP1 and downregulation of MRP2, MRP4, BCRP, and OATP1B3. In the case of NTCP, OATP2B1, and OCT1, a decrease in the protein levels was observed in the class B livers. In the class C livers, no other changes were noted than those in the class A and B patients. The results of the study demonstrate that drug transporter protein abundances are affected by the functional state of the liver in hepatitis C patients.

Keywords: Child–Pugh score; cirrhosis; drug transporter; hepatitis C; liquid chromatography-mass spectrometry; liver; protein quantification; real-time PCR.

Figure 1

Gene expression (left) and protein abundance (right) of ABC transporters in livers from hepatitis C (HCV, n = 58) patients, also subdivided according to the Child–Pugh score into stages: A (n = 30), B (n = 21) and C (n = 7), presented in boxes on the right side to the control livers (n = 20). The data are represented as box plots of the median (horizontal line), 75th (top of box), and 25th (bottom of box) quartiles; the smallest and largest values (whiskers) and mean (+) are shown. mRNA level of the analyzed genes was expressed as relative amounts to the mean value for the control group (ΔΔCT method). Statistically significant differences: * p < 0.05, ** p < 0.01, *** p < 0.001 (Kruskal–Wallis test or Mann–Whitney U test) in comparison to the controls.

Figure 2

Gene expression (left) and protein abundance (right) of SLC transporters in livers from hepatitis C (HCV, n = 58) patients, also subdivided according to the Child–Pugh score into stages: A (n = 30), B (n = 21), and C (n = 7), presented in boxes on the right side to the control livers (n = 20). The data are represented as box plots of the median (horizontal line), 75th (top of box), and 25th (bottom of box) quartiles; the smallest and largest values (whiskers) and mean (+) are shown. mRNA level of the analyzed genes was expressed as relative amounts to the mean value for the control group (ΔΔCT method). Statistically significant differences: * p < 0.05, ** p < 0.01, *** p < 0.001 (Kruskal–Wallis test or Mann–Whitney U test) in comparison to the controls.

Figure 3

The pie chart of the individual drug transporter proteins in the control livers, as well as in hepatitis C livers stratified according to Child–Pugh score (Ch-P class A, B, or C). The pie charts show the abundance of each transporter protein as a percentage of the sum of all transporter proteins’ abundance. Percentages in brackets indicate a total transporter protein abundance in comparison to that in the control livers (indicated as 100%).