Impact of Interleukin-6 on Drug-Metabolizing Enzymes and Transporters in Intestinal Cells

Inflammatory response is characterized by an increase of several cytokines. Some are known to modify drugs pharmacokinetic by reducing the expression levels of drug-metabolizing enzymes (DMEs) and transporters. This impact of inflammatory signaling is well established in hepatic cells, but not in intestinal cells. EpiIntestinal is a 3D human small intestinal tissue model with epithelial polarity, allowing good evaluation of metabolism and drug transport. This study aimed to analyze the effect of IL-6 on this tissue model. RNA sequencing was performed in cells incubated with 5, 10, or 20 ng/mL IL-6 for 8 h to 72 h to study the impact of IL-6 on drug metabolism and pharmacokinetics gene expression. The influence of IL-6 on the activity of cytochromes P450 (CYPs) was studied by measuring metabolite formation of specific substrates with LC-HRMS. Its impact on ATP-binding cassette (ABC) transport was evaluated by measuring intra- and extracellular substrates using spectrofluorometry. Exposure of EpiIntestinal cells to IL-6 resulted in reduction of some CYP mRNAs, such as CYP2C19, CYP2C9, and CYP3A4, by 40% to 50%. Activities of these CYPs were also decreased in EpiIntestinal cells by 20% to > 75%. IL-6 exposure did not modify ABCB1 and ABCCs transporter activities in this model. This study shows that gene expression levels and activities of drug-metabolizing enzymes and ABC transporters may be altered by the pro-inflammatory cytokine IL-6 in intestinal cells. If these results are confirmed in vivo, it may result in pharmacokinetic modifications, such as pre-systemic metabolism, with clinical effects, and require dosage adaptation.