In the July 18 issue of PNAS, Researchers at the Salk Institute in San Diego in collaboration with a laboratory at the Center for Regenerative Medicine in Barcelona converted umbilical cord blood stem cells into nerve cells by expressing just one gene.
The gene that produces this cell transformation is the transcription factor Sox2. The Sox2 gene is one of a handful of transcription factors associated with stem cell differentiation. Transciption factors function like a master switch to turn on and off a different sets of genes to activate biological processes.
The researchers saw that, after getting the Sox2 gene into umbilical cord blood progenitor cells, the cells began to express nerve-cell proteins almost right away. After just a couple replications, they started looking like neurons with elongated dendrite-type filaments. It took about a month for the cells to mature and look like fully grown nerve cells. At that point, the cells on culture plates were able to carry electrical signals like normal nerve cells and, when injected into the brains of young mice, the cells integrated seamlessly with the mouse's developing neural cell network over the course of several weeks.
The current work is the first time human blood cells have been converted to nerve cells with the addition of just one gene. In related work just last month, researchers from the Gladstone Institute were able to convert adult skin stem cells to nerve cells with the same Sox2 transcription factor. The two studies together should provide important information for understanding of how cells become nerves, and perhaps, what is needed to eventually produce nerve cells for use in clinical therapies for stroke, brain and spinal injuries, Parkinson's, and Alzheimer's .