Transporters in membrane vesicles

Transcription

1 Transporters in membrane vesicles LIMO award 2011 for technical excellence NCMLS building Jeroen van den Heuvel Dept Pharmacology & Toxicology Radboud University Nijmegen Medical Centre DNA helix staircase

2 Introduction Medicine use Biodistributionof pharmaceuticals important for safety and efficacy Transporters in intestine, liver, kidney and blood-brain-barrier relevant for pharmacokinetics

3 Introduction Proximal tubule cell Membrane transporters are responsible for uptake and excretion of pharmaceuticals blood MRP2 urine ATP-binding cassette: Efflux Use ATP OAT1 MRP4 P-gp Solute carrier: Uptake Gradient Cooperation of families important for: Efficacy Toxicity OAT3 OCT2 URAT1 BCRP

4 Introduction Why transporters in membrane vesicles: Membrane vesicle In vitro prediction of drug transport Drug-drug interactions Screening for new substrates/inhibitors Characterization of transporter kinetics

5 At that time 2002 started at department Pharmacology & Toxicology 2 important efflux transporters MRP2 and MRP4 were investigated The methods used: Expression with baculovirus in Sf9 insect cells Transport assay with single filter vacuum manifold Main goal: Optimization of vesicle transport assay

6 Objectives Introducing efficient cloning strategy Expression in mammalian cells instead of insect cells HEK293 cells versus Sf9 cells Higher throughput From single filter to 96-wells plate Functional expression of complete set of membrane transporters Efflux transporters Uptake transporters

7 Gateway cloning cdna AttB1 PCR product Gene of interest AttB2 + attp1 pdonr221 Kan(R) BP Clonase TM Cm(R) attp2 ccdb Homologue recombination ccdb gene Multiple expression vectors p10 CMV Chlor amp BacMam- VSV-Dest VSV-G GentR ccdb AmpR Tn7R Tn7L LR Clonase TM + pentr- Gene Gene CMV ppolh p10 Tn7L Amp-r BacMam- VSV-EX-Gene VSV-G Tn7R Gm-r ori

8 Recombinant baculovirus production BacMam expression vector Baculovirus CMV promoter VSV-G protein expression Gene Tn7L ppolh CMV p10 Amp-r BacMam- VSV-EX-Gene VSV-G Gm-r Tn7R ori Bac-to-Bac Recombinant Baculovirus VSV-G VSV-G expression and virus amplification

9 Transduction HEK293 cells transduced with recombinant baculovirus Large-scale triple flask production

10 Membrane vesicles isolation Protease inhibitors Lyse cells: Douncing Centrifuge steps -Remove debris at 4000x g -Membranes at x g Syringe

11 Transport assay Single filter versus 96-wells plate Max. 100 samples a day More than 500 samples a day Optimization and standardization of 96-wells screening method Incubation in 96-wells plate instead of single reaction tube Repetition pipet and multichannel Filtration with 96-wells multiscreen HTS vacuum manifold

12 Detection Radiolabeled 3 H-labels Liquid scintillation counter Fluorescent HPLC LC-MS/MS

13 Expression and functionality differences of Sf9 versus HEK293 cells Expression Sf9 versus HEK293 Functionality Sf9 versus HEK293 Mock Sf9-MRP4 HEK293-MRP4 Deglycosylated HEK293-MRP Sf9 cells show no glycosylation in contrast to HEK293 cells 10 times increase in transport (fmol/mg. min)

14 Functional expression of MRP1-5, BCRP, P-gpand URAT1 MRP1 E 2 17βG transport MRP2 E 2 17βG transport MRP3 E 2 17βG transport MRP4 E 2 17βG transport Transport (pmol / mg * min) Transport (pmol / mg * min) Transport (pmol / mg * min) Transport (pmol / mg * min) Expression Expression Expression Expression Mock MRP1 Mock MRP2 Mock MRP3 Mock MRP4 MRP5 MTX transport BCRP E 1 Stransport P-gp NMQ transport URAT1 Urate transport Transport (pmol / mg * min) Transport (pmol / mg * min) Transport (pmol / mg * min) Transport (pmol / mg * min) Expression Expression Expression Expression Mock MRP5 Mock BCRP Mock P-gp Mock URAT1

15 Characterization and drug-drug interaction of MRP2 and MRP4 BCRP P-gp El-Sheikh AA, van den Heuvel JJ, Koenderink JB, Russel FG. J Pharmacol Exp Ther. 2007; 320(1):229-35

16 Characterization MRP4 mutants By making amino acid changes in MRP4 substrate specificity can be studied MRP4 model El-Sheikh AA, van den Heuvel JJ, Krieger E, Russel FG, Koenderink JB. Mol Pharmacol. 2008; 74(4): wells multiscreen transport assay suitable for screening and characterization of mutants

17 Overview of transporters ATP-binding cassette transporters Solute carrier transporters

18 Summary Efficient gateway cloning Functional expression of several membrane transporters in HEK293 cells 96-wells multiscreentransport assay is suitable for screening and characterization From 100 to 500 samples a day 7 published papers with this technique Functional activity of your membrane transporter in 2-3 months Membrane vesicles transport assay is a powerful method to understand the mechanism of biodistributionof pharmaceuticals in our body

19 Future directions Improve functionality of cloned transporters Include more ATP-binding cassette and solute carrier transporters Own research Cooperation pharmaceutical industry Purify membrane transporters Increase throughput, (96-wells 384-wells chip)

20 Acknowledgements LIMO-FIGON FransRussel, Jan Koenderinkand colleagues of dept. Pharmacology & Toxicology