Adult cell fate reprogramming: converting liver to pancreas.

Regenerative medicine aims at producing new cells for repair or replacement of diseased and damaged tissues. Embryonic and adult stem cells have been suggested as attractive sources of cells for generating the new cells needed. The leading dogma was that adult cells in mammals, once committed to a specific lineage, become "terminally differentiated" and can no longer change their fate. However, in recent years increasing evidence has accumulated demonstrating the remarkable ability of some differentiated cells to be converted into a different cell type via a process termed developmental redirection or adult cells reprogramming. For example, abundant human cell types, such as dermal fibroblasts and adipocytes, could potentially be harvested and converted into other, medically important cell types, such as neurons, cardiomyocytes, or pancreatic beta cells. In this chapter, we describe a method of activating the pancreatic lineage and beta-cells function in adult human liver cells by ectopic expression of pancreatic transcription factors. This approach aims to generate custom-made autologous surrogate beta cells for treatment of diabetes, and possibly bypass both the shortage of cadaveric human donor tissues and the need for life-long immune-suppression.