Generation of liver bipotential organoids with a small-molecule cocktail. Wang Xin,Ni Chao,Jiang Ning,Wei Jinsong,Liang Jianqing,Zhao Bing,Lin Xinhua Journal of molecular cell biology Understanding the mechanism of how cholangiocytes (liver ductal cells) are activated upon liver injury and specified to hepatocytes would permit liver regenerative medicine. Here we achieved long-term in vitro expansion of mouse liver organoids by modulating signaling pathways with a combination of three small-molecule compounds. CHIR-99021, blebbistatin, and forskolin together maintained the liver organoids in bipotential stage with both cholangiocyte- and hepatocyte-specific gene expression profiles and enhanced capacity for further hepatocyte differentiation. By employing a chemical approach, we demonstrated that Wnt/β-catenin, NMII-Rac, and PKA-ERK are core signaling pathways essential and sufficient for mouse liver progenitor expansion. Moreover, the advanced small-molecule culture of bipotential organoids facilitates the ex vivo investigation of liver cell fate determination and the application of organoids in liver regenerative medicine. 10.1093/jmcb/mjaa010