Detection and Quantification of Drug-Protein Adducts in Human Liver

ABSTRACT: Protein adducts formed by drugs or their reactive metabolites are risk factors for adverse reactions, toxicity and inactivation of cytochrome P450 (CYP) enzymes. Characterization of drug-protein adducts is limited due to lack of methods capable of discovering the proteins and peptides adducted by reactive metabolites in complex matrices. The current study presents a proteomics workflow that achieves this task. This workflow combines data-dependent, and data independent acquisition (DDA and DIA) based LC-MS/MS and is sensitive enough to detect very low abundance adducts resulting from CYP mediated drug metabolism in human livers. Human liver microsomes (HLMs) or recombinant CYPs were incubated with raloxifene as a model compound. The resulting adducts were identified using this workflow. In HLMs, raloxifene adducts were detected in 78 proteins, including multiple adducts in CYP3A and CYP2C family enzymes. Experiments with recombinant CYP3A and CYP2C enzymes confirmed adduct formation in all CYPs tested, including CYPs not subject to time dependent inactivation (TDI) by raloxifene. These data suggest many adducts formed by reactive intermediates are benign. DIA analysis showed variable abundance of raloxifene adducts in many proteins between livers, but no concomitant decrease in abundance of unadducted peptides. The current study sets a new standard for adduct detection in complex samples, offering valuable insights into the human adductome resulting from exposure to reactive metabolites. The developed methodology forms a foundation for mechanistic studies to identify, quantify and differentiate between adducts that result in adverse drug reactions and drug-drug interactions and adducts that do not.

ORGANISM(S): Homo Sapiens Spodoptera Frugiperda

SUBMITTER: Alex Zelter  

PROVIDER: PXD054246 | panorama | Fri Oct 25 00:00:00 GMT+01:00 2024

REPOSITORIES: PanoramaPublic