A roadmap for early human liver development from pluripotent stem cells

Embryonic stem cells (ESCs) have the potential to yield new liver cells for regenerative medicine. However it has been challenging to generate homogeneous ESC-derived human liver populations capable of engrafting in vivo and ameliorating liver failure. To overcome this challenge, we define extrinsic signals regulating six consecutive stages of human liver development, including patterning of endoderm into foregut, liver bud specification, and segregation of hepatocyte vs. biliary fates. This knowledge enabled differentiation of human ESCs into 89% pure AFP+HNF4A+TBX3+ liver bud progenitors and subsequently, a >77% uniform ALB+ hepatocytic population. ESC-derived ALB+ human hepatocytic cells engrafted the damaged livers of Fah-/- mice, improving overall mouse survival and reducing liver damage. Interestingly, certain signals that matured hESC-derived hepatocytic cells also sustained primary adult hepatocytes in vitro for one week. Collectively we demarcate extrinsic signaling, mRNA and surface marker dynamics during human liver development, enabling the generation of engraftable liver cells from ESCs. 32 samples consisting of H1 hESCs differentied into D2 definitive endoderm, D6 liver bud and D12 hepatic progenitors with the full base condition, without Notch inhibitor DAPT, without Forskilin, without AAP or without insulin.