Adult skin cells have been transformed directly into neurons by two independent groups in China using just small-molecule chemicals.
Reprogramming adult cells back into stem cells or directly into other types of specialized cells requires transcription factors, which modify cells genetically. To avoid tinkering with the cells' genes, Gang Pei and Jian Zhao from the Shanghai Institutes for Biological Sciences and their colleagues worked with fibroblasts, or skin cells, from both healthy adults and people with Alzheimer's disease, culturing them with a cocktail of small molecules to produce neurons.
Hongkui Deng at Peking University, Beijing, and his colleagues used a different set of chemicals to convert mouse fibroblasts into neurons. Both groups made neurons that looked, fired and made functional connections just like neurons created from fibroblasts using transcription factors.
The chemicals modulate key molecular signalling pathways to change an adult cell's identity. This approach could make it easier to reprogram cells for clinical use, say the authors.