Efficient induction of functional neurons from adult human fibroblasts.

Cellular reprogramming is a rapidly developing technology by which somatic cells are turned into pluripotent stem cells or other somatic cell types through expression of specific combinations of genes. This allows for the generation of patient-specific cell lines that can serve as tools for understanding disease pathogenesis, for drug screens and, potentially, for cell replacement therapies. Several cellular models of neurological disorders based on induced pluripotent cells (iPS cells) have been developed, and iPS-derived neurons are being explored as candidates for transplantation. Recent findings show that neurons can also be induced directly from embryonic and postnatal somatic cells by expression of defined combinations of genes. This conversion does not occur through a pluripotent stem cell stage, which eliminates the risk for tumor formation. Here, we demonstrate for the first time that functional neurons can be generated via direct conversion of fibroblasts also from adult individuals. Thus, this technology is an attractive alternative to iPS cells for generating patient- and disease-specific neurons suitable for disease modeling and autologous transplantation.