Astrocyte-specific deletion of SOX2 promotes recovery after traumatic brain injury

Injury to the adult brain induces activation of resident astrocytes, which serves as a compensatory response modulating tissue damage and recovery. However, the mechanism governing astrocyte activation and the role of reactive astrocytes remain largely unknown. Here we show that SOX2, a transcription factor critical for stem cells and brain development, is also required for injury-induced activation of adult cortical astrocytes. Genome-wide ChIP-seq analysis reveals that SOX2 binds to regulatory regions of genes associated with signaling pathways controlling reactive gliosis, such as Socs3, Nr2e1, Notch1, and Akt2. Inducible deletion of Sox2 in adult astrocytes greatly diminishes their response to traumatic injury and, most unexpectedly, restricts injury-induced cortical loss. Together, these results uncover an essential role of SOX2 in terminally differentiated cells and implicate that SOX2-dependent reactive astrocytes may be targeted for regeneration after traumatic brain injury.