Here, we describe a protocol to develop a three-dimensional (3D) liver bud-like tissue from human iPSCs in vitro. This method mainly consists of two parts: (1) hepatic endoderm (HE) differentiation from human iPSCs in 2D culture and (2) co-culturing iPSC-HE with endothelial and mesenchymal cells. First, iPSCs were differentiated into definitive endoderm (DE) cells, and the DE cells were differentiated into HE cells, which were then co-cultured with endothelial cells and mesenchymal cells on Matrigel-coated plastic plates or micropattern plates. The cells rapidly condensed to generate 3D tissue masses. We named these iPSC liver buds (iPSC-LBs) because they resemble the developing liver bud from the perspective of gene expression, cell proliferation, and cell proportion. This liver bud culture system provides a novel approach for future clinical applications, for drug development, and as a tool for studying human development.
Keywords: Drug development; Human-induced pluripotent stem cells; Liver bud; Multicellular interaction; Regenerative medicine; Self-organization; Three-dimensional culture.