A Comparative View on Human Somatic Cell Sources for iPSC Generation

Figure 1

Reprogramming of keratinocytes. (1) Plucked hair is cultured in flasks until outgrowth of keratinocytes. Those are transferred to a six-well plate. (2) Keratinocytes are infected with a lentivirus containing the four reprogramming factors OCT4, SOX2, KLF4, and C-MYC. (3) Infected keratinocytes are transferred to a plate with feeder cells (e.g., rat embryonic fibroblasts) in reprogramming medium. (4) After two to three weeks, stem cell colonies arise, and the uninfected keratinocytes do not proliferate in the reprogramming medium. (5) When the stem cell colonies reach a certain size, they are picked mechanically and a feeder-free system may be used for cultivating the human iPSCs.