Modeling Human Bile Acid Transport and Synthesis in Stem Cell-Derived Hepatocytes with a Patient-Specific Mutation

• Published in: Stem cell reports Vol. 16; no. 2; pp. 309 - 323
• Main Authors: Hayashi, Hisamitsu, Osaka, Shuhei, Sakabe, Kokoro, Fukami, Aiko, Kishimoto, Eriko, Aihara, Eitaro, Sabu, Yusuke, Mizutani, Ayumu, Kusuhara, Hiroyuki, Naritaka, Nakayuki, Zhang, Wujuan, Huppert, Stacey S., Sakabe, Masahide, Nakamura, Takahisa, Hu, Yueh-Chiang, Mayhew, Christopher, Setchell, Kenneth, Takebe, Takanori, Asai, Akihiro
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 09.02.2021; Elsevier
• Subjects: bile acid synthesis; bile acid transport; CRISPR genome editing; hepatic differentiation; iPSC; PFIC2; progressive familial intrahepatic cholestasis; hepatic differentiation; iPSC; progressive familial intrahepatic cholestasis; PFIC2; bile acid synthesis; bile acid transport; CRISPR genome editing
• ISSN: 2213-6711; 2213-6711
• DOI: 10.1016/j.stemcr.2020.12.008

The bile salt export pump (BSEP) is responsible for the export of bile acid from hepatocytes. Impaired transcellular transport of bile acids in hepatocytes with mutations in BSEP causes cholestasis. Compensatory mechanisms to regulate the intracellular bile acid concentration in human hepatocytes with BSEP deficiency remain unclear. To define pathways that prevent cytotoxic accumulation of bile acid in hepatocytes, we developed a human induced pluripotent stem cell-based model of isogenic BSEP-deficient hepatocytes in a Transwell culture system. Induced hepatocytes (i-Heps) exhibited defects in the apical export of bile acids but maintained a low intracellular bile acid concentration by inducing basolateral export. Modeling the autoregulation of bile acids on hepatocytes, we found that BSEP-deficient i-Heps suppressed de novo bile acid synthesis using the FXR pathway via basolateral uptake and export without apical export. These observations inform the development of therapeutic targets to reduce the overall bile acid pool in patients with BSEP deficiency. [Display omitted] •Human isogenic iPSCs were generated by CRISPR to study a truncating mutation of BSEP•iPSC-derived hepatocytes recapitulate pathophysiology of BSEP deficiency in patients•BSEP-deficient hepatocytes induce alternative basolateral bile acid export•Activation of FXR suppresses de novo bile acid synthesis in BSEP-deficient hepatocytes In this study, Asai and colleagues provide proof of concept of novel disease modeling for human genetic liver disorders caused by bile acid transport defects. A bile salt export pump (BSEP) mutation in isogenic iPSC-derived hepatocytes recapitulated the disease phenotype. This novel model revealed adaptive reverse bile acid exports in BSEP-deficient hepatocytes while maintaining regulatory feedback of de novo bile acid synthesis.