Reprogramming of Keratinocytes as Donor or Target Cells Holds Great Promise for Cell Therapy and Regenerative Medicine.

One of the most crucial branches of regenerative medicine is cell therapy, in which cellular material is injected into the patient to initiate the regenerative process. Cells obtained by reprogramming of the patient's own cells offer ethical and clinical advantages could provide a new source of material for therapeutic applications. Studies to date have shown that only a subset of differentiated cell types can be reprogrammed. Among these, keratinocytes, which are the most abundant proliferating cell type in the epidermis, have gained increasing attention as both donor and target cells for reprogramming and have become a new focus of regenerative medicine. As target cells for the treatment of skin defects, keratinocytes can be differentiated or reprogrammed from embryonic stem cells, induced pluripotent stem cells, fibroblasts, adipose tissue stem cells, and mesenchymal cells. As donor cells, keratinocytes can be reprogrammed or direct reprogrammed into a number of cell types, including induced pluripotent stem cells, neural cells, and Schwann cells. In this review, we discuss recent advances in keratinocyte reprogramming, focusing on the induction methods, potential molecular mechanisms, conversion efficiency, and safety for clinical applications. Graphical Abstract KCs as target cells can be reprogrammed or differentiated from fibroblasts, iPSCs, ATSCs, and mesenchymal cells. And as donor cells, KCs can be reprogrammed or directly reprogrammded into iPSCs, neural cells, Schwann cells, and epidermal stem cells.