Bile canaliculi formation using human-derived hepatocyte resources

Abstract

Severe liver injury is a cause of drug development discontinuation or market withdrawal, and there is a need to improve the predictability of adverse hepatic events in the early stages of development. Among these, drug-induced cholestasis has been difficult to reproducibly and sensitively evaluate in vitro because of the difficulty in forming a bile canaliculi network capable of excreting bile using human hepatocyte culture. In addition, since there are species differences in bile excretion, there is a need for an in vitro test system that can evaluate the risk of cholestasis in humans without relying on animal experiments. Based on the above background, we have attempted to establish a culture method to form a bile canaliculi network capable of bile excretion in human cryo-preserved hepatocytes. We first found that long-term culture of iPS cell-derived hepatocytes promotes the formation of bile canaliculi. (Horiuchi et al. Sci Rep. 2022) Using this culture method, we are now analyzing the formation of bile canaliculi in cryo-preserved human hepatocytes from multiple donors and evaluating differences in bile excretion capacity among donors. We have also found that bile ducts are formed in hepatocytes derived from human liver chimeric mice. Based on the above findings, we re-evaluate hepatocytes from the viewpoint of bile excretion, and consider the characteristics of hepatocytes required for the in vitro assasy system as “hepatocyte-ness.”