ABSTRACT
Organoid generation from pluripotent stem cells is a cutting-edge technique that has created new possibilities for modelling human organs in vitro, as well as opening avenues for regenerative medicine. Here, we present a protocol for generating skin organoids (SKOs) from human-induced pluripotent stem cells (hiPSCs) via direct embryoid body formation. This method provides a consistent start point for hiPSC differentiation, resulting in SKOs with complex skin architecture and appendages (e.g. hair follicles, sebaceous glands, etc.) across hiPSC lines from two different somatic sources.
ABSTRACT
The development of skin organs for studying developmental pathways, modeling diseases, or regenerative medicine purposes is a major endeavor in the field. Human induced pluripotent stem cells (hiPSCs) are successfully used to derive skin cells, but the field is still far from meeting the goal of creating skin containing appendages, such as hair follicles and sweat glands. Here, the goal is to generate skin organoids (SKOs) from human skin fibroblast or placental CD34+ cell-derived hiPSCs. With all three hiPSC lines, complex SKOs with stratified skin layers and pigmented hair follicles are generated with different efficacies. In addition, the hiPSC-derived SKOs develop sebaceous glands, touch-receptive Merkel cells, and more importantly eccrine sweat glands. Together, physiologically relevant skin organoids are developed by direct induction of embryoid body formation, along with simultaneous inactivation of transforming growth factor beta signaling, activation of fibroblast growth factor signaling, and inhibition of bone morphogenetic protein signaling pathways. The skin organoids created in this study can be used as valuable platforms for further research into human skin development, disease modeling, or reconstructive surgeries.