Interplay of Alcohol Intake, Smoking, and Sex on the Protein Abundance of Hepatic Drug Metabolizing Enzymes and Transporters in Humans

Abstract ID 100511 Poster Board 237 Alcohol and tobacco are widely used worldwide and are associated with numerous health risks. The effects of alcohol and smoking on drug-metabolizing enzyme and transporter (DMET) protein levels can have notable implications for drug interactions; however, a comprehensive picture of these effects is lacking. While alcohol is known to induce cytochrome P450 2E1 (CYP2E1), there are several reports suggesting alcohol modulation of other CYPs, UDP-glucuronosyltransferases (UGTs), and transporters in cell cultures and animal models. Similarly, nicotine and other components of tobacco smoke are extensively metabolized by CYPs, particularly CYP2A6, as well as UGTs and flavin-containing monooxygenases (FMOs), the induction of which may confound the effects of alcohol on the expression levels of DMET proteins. However, no comprehensive study exists regarding DMET protein abundance profiling related to human alcohol and smoking consumption. In this study, we quantified protein abundance of DMET proteins in human liver microsomes (HLM) isolated from liver tissues from 82 adult donors (52 males and 30 females) to investigate the effect of alcohol intake, smoking history, and sex. Samples were digested by trypsin and data were acquired using a Q-Exactive HF mass spectrometer and analyzed using DIA-NN software and the total protein approach was used for quantification to compare abundance and composition of DMET proteins. Out of >3000 proteins detected in HLM samples, protein levels of DMET proteins were analyzed in relation to alcohol consumption grades, smoking history data, and sex using non-parametric tests (p-value ≤ 0.05; cutoff of 1.25-fold change, FC). Consistent with literature reports, heavy alcohol intake (n = 6) was associated with significant upregulation of CYP2E1 (1.7-fold) and UGT1A6 (1.4-fold) when compared to non-drinkers (n = 31). Interestingly, significant decreases in CYP1A1 (FC 0.6), CYP1A2 (FC 0.4), CYP4A11 (FC 0.6), and CYP4F2 (FC 0.7); UGT1A3 (FC 0.6), UGT2B7 (FC 0.7), and UGT2B15 (FC 0.7); and FMO5 (FC 0.4) levels were detected in HLM from heavy drinkers versus non-drinkers. The alcohol effects were similar in smokers versus non-smokers. Individuals with a history of moderate and heavy smoking (>1 pack a day; n = 13) were associated with significant upregulation of CYP1A2 (1.5) and significant downregulation of CYP4F22 (FC 0.6), FMO1 (FC 0.8) and FMO5 (FC 0.7) as compared to non-smokers (n = 60), independent of alcohol consumption. Male donors (n = 52) showed significantly higher abundance of CYP1A2 (FC 1.4), UGT2B17 (FC 4.5), UGT2B15 (FC 1.5), and a significantly lower abundance of UGT2A3 (FC 0.75) as compared to females (n = 30). While an association of UGT2B17 abundance with sex is well-known, the effect of sex on other DMET proteins of clinical importance is a novel finding. This is the first study to our knowledge to report effects of alcohol intake, smoking, and sex differences on the protein levels of important DMET proteins, which are involved in the metabolism of a variety of pharmaceuticals. Our data show that not only are there alcohol-associated differences in DMET abundance and composition, but also that smoking history and sex should be considered as co-variates, the interplay of which could impact drug pharmacokinetics, efficacy, and toxicity. Funding source: This work was funded by NIAAA R01-AA030155.