The Potential of Using Induced Pluripotent Stem Cells in Skin Diseases

The seminal discovery of induced pluripotent stem cells (iPSCs) and subsequent expansion in iPSC research have greatly aided our understanding of stem cell biology and have catapulted the changing face of regenerative medicine into prominence. With easy accessibility and visibility, the skin has been considered a favorable organ to study stem cell behaviors. In particular, the skin provides valuable materials for tissue engineering and testing of novel therapeutic approaches including gene therapy and regenerative medicine. The skin consists of multiple cell lineages, including interfollicular/follicular keratinocytes, melanocytes, sebocytes, and follicular/intradermal mesenchymal cells. Nowadays, iPSCs can be generated from various skin-derived cell populations. Elegant label-tracking experiments have successfully identified their stem/early precursor cell populations. Following molecular and cellular biological experimentations and transgenic studies the elucidation of necessary factors, signaling networks, environments supporting their behavior, and interactions in organogenesis and homeostasis have been uncovered. Taking advantage of the knowledge accumulated by these works, iPSC-derived keratinocytes and melanocytes have been successfully induced, which holds promise as future materials for the bioengineering of the skin and hair, and investigation of biology of skin stem cells. Recently, the concept of cancer stem cells (CSCs) has been proposed. Cancer stem cells have been implied to originate from stem cell subsets and, accordingly, iPSCs may be converted to skin CSCs, especially most life-threatening melanoma CSCs. Those iPSC-derived CSCs may significantly enhance our understanding of cancer biology and allow the development of novel therapeutic strategies. Recently, patient-specific iPSCs were established from intractable genodermatoses, including epidermolysis bullosa, and corrected for their genetic defects. Thus, iPSC technology should open a new era of stem cell biology, genetic/regenerative medicine and oncology in the field of dermatology.