Characterising a HepaRG liver microphysiological system for individual bile acid secretion and chemical induced disruptions.

Liver microphysiological systems (MPS) have gained increasing attention as human-relevant models for chemical safety assessments, particularly for studies with defined endpoints, such as cholestatic injury. In this study, we built upon a previously established HepaRG-based liver MPS model using the OrganoPlate® 3-lane system. Our aim in this proof-of-concept study was to characterise the synthetic capacity and metabolic function, focusing on the bile acid secretion, under both basal and chemically treated conditions at three independent time points. Undifferentiated HepaRG cells were seeded into the perfusion channels coated with Matrigel and cultured under flow condition without the addition of dimethyl sulfoxide (DMSO). We monitored cell self-organisation, health, and maturation using microscopy, viability assays, albumin and individual bile acid secretion profiling, and gene expression analysis. To assess the metabolic competence and treatment responses regarding the bile acid secretion, the cells were exposed to rifampicin and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 48 h. Despite the absence of DMSO supplementation, HepaRG cells self-organised into maturing aggregates and demonstrated inducible CYP1A2 and CYP3A4 activity by day 3. Although the synthetic capacity was generally low, the model secreted all primary (conjugated) bile acids and exhibited clear time-dependent changes in the bile acid composition under treatment. These proof-of-concept findings highlight the potential of flow conditions to enable in situ HepaRG maturation and represent a promising step toward defining a potential context of use as a tool for cholestatic injury.