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.

中文翻译：

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用小分子鸡尾酒生成肝脏双电位类器官

了解胆管细胞（肝导管细胞）在肝损伤时如何被激活并指定为肝细胞的机制将允许肝脏再生医学。在这里我们实现了长期体外通过用三种小分子化合物的组合调节信号通路来扩展小鼠肝脏类器官。CHIR-99021、blebbistatin 和 forskolin 共同将肝脏类器官维持在双电位阶段，同时具有胆管细胞和肝细胞特异性基因表达谱，并增强了进一步肝细胞分化的能力。通过采用化学方法，我们证明了 Wnt/β-catenin、NMII-Rac 和 PKA-ERK 是小鼠肝脏祖细胞扩增必不可少且充分的核心信号通路。此外，双潜能类器官的先进小分子培养促进了肝细胞命运决定的离体研究和类器官在肝脏再生医学中的应用。