Cellular Reprogramming in Basic and Applied Biomedicine: The Dawn of Regenerative Medicine

Fertilization triggers a cascade of cellular and molecular events restoring the totipotent state and the potential for all cell types. However, the program quickly directs differentiation and cellular commitment. Under the genetic and epigenetic control of this process, Waddington likened this to a three-dimensional landscape where cells could not ascend the slope or traverse once canalized thus leading to cell fate decisions and the progressive restriction of cellular potency. But this is not the only possible outcome at least experimentally. Somatic cell nuclear transfer and overexpression of key transcription factors to generate induced pluripotent cells have challenged this notion. The return to pluripotency and the reinstatement of plasticity and heterogeneity once thought to be the exclusive remit of the developing embryo can now be replicated in vitro. The following chapter introduces some of these ideas and suggests that the fundamental principles learned may constitute the first step toward the opportunity for specific tissue renewal and replacement in healthy aging and the treatment of chronic diseases-the age of regenerative medicine.