Guo Z. et al. Cell Stem Cell doi:10.1016/j.stem.2013.12.001 (19 December 2013).

A common hallmark of injured brain areas is the appearance of a 'gliotic scar'. Gliosis involves the activation of glial cells such that they proliferate and secrete factors that can prevent neuronal growth and recovery. Reactive glial cells—including astrocytes, oligodendrocyte precursors (NG2 cells) and microglia—can be detected in brains from patients that have suffered from stroke, glioma or neurodegeneration. Guo et al. devised a strategy to reprogram activated glial cells into functional neurons in adult mouse brains, possibly providing new ways of promoting recovery of injured or diseased brains. They did this by using retroviruses, which selectively target dividing cells in the brain (such as reactive glial cells or progenitor cells), and overexpressing in these cells the transcription factor NeuroD1. This single transcription factor was able to reprogram astrocytes into glutamatergic neurons and NG2 cells into both glutamatergic and GABAergic neurons.