Drug-induced liver injury (DILI) remains a challenge and a leading risk for drug discovery. Three-dimensional liver spheroids made from primary human hepatocytes (PHHs) with, or without, other liver cell types can provide more physiological relevance. In comparison to conventional 2-dimensional monolayer culture, our tests with 100 drugs of known DILI status indicate that PHH spheroids are significantly more sensitive in detecting drug-induced hepatotoxicity. To evaluate the role of Kupffer cells (KCs) in drug-induced liver toxicity, we have established conditions for generating co-culture spheroids with PHH and KCs. Inflammatory responses as shown by interleukin 6 secretion can be recapitulated in co-culture spheroids when treated with endotoxin lipopolysaccharides. KCs potentiated the cytotoxicity induced by trovafloxacin in co-culture spheroids at 48 h, but the differences between PHH spheroids and co-culture spheroids became less obvious after a 5-day treatment. Interestingly, a protective role of KCs was shown in co-culture spheroids treated with both acetaminophen and lipopolysaccharides. Additional tests with 14 DILI compounds comparing PHH spheroids and co-culture spheroids showed differential roles of KCs that were compound dependent. In summary, these 3-dimensional liver spheroid models are useful tools to understand the complex mechanisms underlying DILI.
