Development of a Chemical Biology Approach to Uncover the Influence of Sequence Variations on CES1 Activity in Live Cells

Abstract

Drug metabolism is the biochemical process of modifying drugs to detoxify and remove them through enzymatic transformations. These biotransformation’s occur primarily in the liver and are critical to understanding how pharmaceutical compounds are chemically altered inside the human body. Human carboxylesterases (CESs) catalyze the hydrolysis of esters, amides, thioesters, and carbamates. CES-mediated hydrolysis plays an important role in the metabolism of many drugs including the first FDA approved antiviral treatment for COVID-19, remdesivir (Veklury), the seizure control medication rufinamide (Banzel), and the flu antiviral drug oseltamivir (Tamiflu). CES activity is known to be influenced by a variety of factors including those that vary CES’s amino acid sequence, including nonsynonymous single nucleotide polymorphisms (nsSNPs), alternative RNA splicing, and alternative translation start sites. This is best reported for one of the two predominant CESs, CES1, where some of these factors have been linked to adverse clinical outcomes when patients are treated with CES1-substrate therapeutics. Despite the importance of CES1 in drug metabolism, the factors that influence the activity of CES1 remain understudied compared to other enzymes involved in drug metabolism. To address this issue, the Beck research group have previously developed a live cell fluorescence microscopy-based assay that can measure the activity called Sequence variant Activity Microscopy (SAM) Assay version 1.0. This thesis work focuses on optimizing this assay to reduce false negatives. Overall, the use of the optimized SAM assay will result in better health outcomes for patients with abnormal CES1 activity.

Date of Award	2023
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Michael W Beck (Supervisor)