High-Throughput Assessment of Bile Salt Export Pump Inhibition Using RapidFire-MS and DESI-MS

Area of Science:

• Pharmacology
• Analytical Chemistry
• Drug Discovery

Background:

• The bile salt export pump (BSEP) is crucial for preventing drug-induced liver injury (DILI).
• Traditional BSEP assays using LC-MS lack the throughput required for early drug candidate screening.
• Efficient methods are needed to assess BSEP inhibition during drug development.

Purpose of the Study:

• To develop and validate high-throughput mass spectrometry methods for label-free BSEP activity assessment.
• To evaluate the potential of new methods for screening drug candidates for DILI risk.
• To compare the performance of solid-phase extraction (SPE) and desorption electrospray ionization (DESI) MS techniques for BSEP assays.

Main Methods:

• Developed two high-throughput mass spectrometry (MS) methods: one utilizing solid-phase extraction (SPE) and another desorption electrospray ionization (DESI).
• Assessed BSEP activity in a label-free manner with minimal sample preparation.
• Achieved rapid sampling rates of approximately 11 seconds/sample (SPE-MS) and 5.5 seconds/sample (DESI-MS).

Main Results:

• Both SPE-MS and DESI-MS methods were validated and compared effectively.
• The methods successfully evaluated 96 drug candidates for their inhibition of taurocholic acid (TCA) transport via BSEP vesicles.
• Demonstrated high-throughput capability for BSEP activity assessment.

Conclusions:

• Novel high-throughput MS methods (SPE-MS and DESI-MS) offer efficient, label-free BSEP activity assessment.
• These methods overcome limitations of traditional assays, facilitating early DILI risk evaluation in drug discovery.
• The developed techniques are suitable for large-scale screening of drug candidates.