Protocol for directed differentiation of human induced pluripotent stem cells into thyroid follicular epithelial cells

We provide a directed differentiation protocol deriving thyroid follicular cells (TFCs) from human induced pluripotent stem cells (iPSCs) or embryonic stem cells without exogenous transcription factors, recapitulating the sequence of developmental milestones of thyroid development. We describe a protocol for seeding iPSCs, inducing definitive and anterior foregut endoderm, followed by thyroid lineage specification via Fibroblast Growth Factor/Bone Morphogenetic Protein (FGF/BMP) signaling and subsequent differentiation and maturation into TFCs. Our protocol is validated using stem cell lines from a variety of human genetic backgrounds. For complete details on the use and execution of this protocol, please refer to Undeutsch et al.¹.