Application of HepaRG mono- and HepaRG:THP-1 cocultures as immune responsive hepatotoxicity models

Embedding immune responsiveness is relevant for hepatotoxic testing strategies, as inflammation can affect the kinetics of compounds by modulation of drug-metabolizing enzymes and transporters (DMETs), and because inflammation is thought to explain some cases of idiosyncratic drug-induced liver injury (iDILI). Therefore, this study applied HepaRG monocultures and HepaRG:THP-1 macrophage cocultures as immune responsive hepatotoxicity models. To induce inflammation, HepaRG and THP-1 macrophages in mono- and coculture were stimulated with lipopolysaccharide (LPS) combined with interferon gamma (IFNγ). Proinflammatory cytokines interleukin (IL)6, IL8, IL1β and tumor necrosis factor alpha (TNFα) were quantified to verify an inflamed-like state. Our results showed that LPS and IFNγ elicited an inflamed-like state in both culture models, characterized by an increase in cytokine secretion. Next, mRNA expression and activity of DMETs was assessed in the stable and inflamed mono- and coculture model. Inflammation reduced the mRNA expression and activity of cytochrome P450 (CYP) enzymes, but did not reduce the mRNA expression and activity of efflux transporters in HepaRG mono- and cocultures. Finally, models were exposed to iDILI drugs diclofenac (200 µM), trovafloxacin (100 µM) and clozapine (75 µM), whereafter cell viability and cytotoxicity was measured. The iDILI drugs induced a synergistic decrease in viability in inflamed HepaRG mono- and cocultures, which showcases predictivity of the model for iDILI hepatotoxic reactions. In conclusion, HepaRG cells in monoculture and in coculture with THP-1 macrophages showed similar inflammation-driven effects on the selected endpoints, which shows that both models are promising tools to evaluate inflammation-driven effects on toxicokinetic and toxicodynamic endpoints.