Bile acid-FXR signaling facilitates the long-term maintenance of hepatic characteristics in human iPSC-derived organoids.

Human induced pluripotent stem cells (iPSCs) can be differentiated into hepatocyte-like cells (iPS-Heps); however, maintaining the long-term proliferation and hepatic characteristics of iPS-Heps remains a challenge. In this study, we aimed to develop a human iPSC-derived hepatic organoid (iHO) culture system that effectively retains hepatic characteristics long term. Our original culture strategy, using bile acids and their receptor (farnesoid X receptor [FXR]) agonists, yielded human iHOs capable of long-term culture with a distinctive "grape-like" structure. Comprehensive analysis showed that these iHOs maintained hepatocyte-like phenotypes, even after multiple passages, whose gene expression profiles were consistent with those of fetal hepatocytes. In addition, the overexpression of small heterodimer partner (SHP), a downstream gene of FXR, in iHOs negatively regulated genes related to the intestine and cholangiocytes. Our data demonstrated that bile acid-FXR signaling promotes both the hepatic characteristics and proliferative potential of iHOs, offering promising potential for future applications in regenerative medicine and as a disease model.