The stem cell cocktail: neural reprogramming just got easier
The unlimited proliferative and developmental potential harbored by stem cells promised to be the ideal source of testing and transplant material necessary to cure many human diseases. In 2006 induced pluripotent stem cells (iPSCs) eliminated host versus graft problems for stem cell therapy and provided new disease modeling avenues (1). Since then, a wide variety of articles on the differentiation of iPSCs towards specific cell lineages again have promised to provide the long-awaited host-specific models and cellular sources to study various human diseases (2,3). However, iPSCs are routinely virally reprogrammed and highly variable (1,4), which raises concerns about their tumorigenicity and reproducibility. Unlike viral reprogramming, small molecules interact with the pre-existing molecular machinery and so can bypass any dormant virus-related tumorigenicity. Also, small molecules could potentially reduce the variability of reprogramming and subsequent differentiation of iPSCs, given the robustness of their production and optimization.