Jawbone-like organoids generated from human pluripotent stem cells.

Engineering jawbone tissues from pluripotent stem cells presents a challenge owing to the lack of protocols for selectively inducing the jawbone progenitor, the first pharyngeal arch (PA1) ectomesenchyme, and for recapitulating three-dimensional osteocyte networks. Here we present a method for generating jawbone-like organoids from human induced pluripotent stem cells through PA1 ectomesenchyme of the mandibular prominence (mdEM). A three-dimensional culture system enables sequential differentiation of induced pluripotent stem cells into neural crest cells and mdEM. The mdEM exhibits proximal-distal patterning from the centre outwards, mirroring mandibular development. The introduction of exogenous pharyngeal epithelial signals induces mandibular prominence-specific regional patterning in the mdEM. When cultured under osteogenic conditions, the mdEM forms jawbone-like organoids comprising osteoblasts and network-forming osteocytes embedded in self-produced mineralized bone matrices. Moreover, these organoids promote bone regeneration when transplanted into jaws containing bone defects and recapitulate phenotypes of osteogenesis imperfecta, a genetic disorder characterized by fragile bones, using patient-derived induced pluripotent stem cells. Our protocols establish a foundation for investigating human jaw embryology and pathophysiology.