Marius Wernig and colleagues, Stanford University, California, USA, have reported a method for generating functional neurons from skin cells. The team used genetically modified viruses to introduce four different transcription factors, Brn2, Ascl1, Myt1l, and the basic helix–loop–helix transcription factor NeuroD1, into fetal skin cells. The resulting neurons responded to electric input by pumping ions across their membranes and were shown to form synapses to pre-existing neurons. Unlike other approaches, this process, called transdifferentiation, does not involve the reprogramming of the skin cells into stem cells, but rather the direct transformation of skin cells into neurons.

Initial applications include the modeling of neurological diseases by creating brain cells for research from the skin of people with neurological conditions. Ultimately, these neurons could be transplanted into pre-existing neuronal networks to treat such conditions.

• Induction of human neuronal cells by defined transcription factors
  Z. P. Pang, N. Yang, T. Vierbuchen, A. Ostermeier, D. R. Fuentes et al.,
  Nature 2011.
  DOI: 10.1038/nature10202