Protein transduction: a novel approach to induce in vitro pancreatic differentiation

It is widely believed that human embryonic stem (huES) cells may represent a valid alternative to donor pancreata as a source of islets for transplantation. Much is known about the transcription factors whose sequential activation results in the generation of islets during pancreatic development. This knowledge has been used to articulate the theoretical possibility that such process might be recapitulated in vitro from stem cells. However, our understanding of the extracellular signals that prompt the developing pancreas to follow this sequence of molecular events is very limited. Also, the simplicity of in vitro systems makes it difficult, if not impossible, to mimic the complex signaling pattern observed in living embryos. Protein transduction (PT) technology may provide researchers with a new powerful tool to sequentially induce stem cell differentiation, entirely bypassing the need for unraveling the signaling pattern that drives the process in vivo. Here we discuss this novel application of the flourishing PT technology, which may revolutionize the way we direct stem cells along any specific lineage.