Generation of 3D tubular bile duct within human iPSC-derived liver organoid by incorporating human iPSC-derived blood vessel [RNA-seq]

Bile duct (BD) structure is crucial for bile secretion to maintain liver homeostasis. Although several human induced pluripotent stem cell (hiPSC)-derived liver organoids have been generated, no study recapitulates the development of BD tubules. Here, we focus on an environmental cue to form tubular BDs, specifically the interaction between liver progenitors with the portal vein (PV). We co-culture hiPSC-liver progenitors with PV-like hiPSC-blood vessel (hiPSC-BV) which consists of immature hiPSC-smooth muscle cells (SMC) with a similar character to fetal PV-SMC. After two weeks, liver progenitors within hiPSC-BV-integrated liver organoid (BVLO) differentiate into the cholangiocyte-lineage and establish tubular structures with epithelial characteristics including intercellular junctions, microvilli on the apical membrane, and secretory functions. Liver surface transplanted BVLO showed further BD maturation and connection to the host BD. Taken together, our study developed a novel 3D co-culture method o establish functional human tubular BDs by recapitulating PV-BD interaction.