Artificial Pigmented Human Skin Created by Muse Cells.

The skin composes physiological and chemical barrier and renews skin component cells throughout the human life. Melanocytes locate in the basal layer of the epidermis and produce melanin to protect the skin from ultraviolet. Melanin plays key roles in determining human skin and hair color. Melanocyte dysfunction observed in albinism and vitiligo not only causes cosmetic problems but also increases risk of skin cancer. As rejuvenate therapy, embryonic stem (ES) cells and induced pluripotent stem (iPS) cells have been reported to generate melanocytes. Other than ES and iPS cells, human skin tissues maintain pluripotent stem cells, named multilineage-differentiating stress-enduring (Muse) cells. We employ Muse cells isolated from human fibroblasts and adipose tissue to differentiate into melanocytes (Muse-MC). Muse-MC express melanocyte-related molecules, such as tyrosinase and DCT, and show tyrosinase activity. We also succeeded to differentiate Muse cells into fibroblasts and keratinocytes and created three-dimensional (3D) reconstituted skin with Muse cell-derived melanocytes, fibroblasts, and keratinocytes. The 3D reconstituted skin of Muse cell-derived cells coordinately showed epidermis layers and Muse-MC localized in the basal layer of the epidermis. Thus Muse cells in the human skin can be a source of rejuvenation medicine for the skin reconstruction.