Neuroscientists at the University of Zurich have identified a specialized class of brain support cells that can rebuild damaged neural tissue in an unexpected way: by sending only their genetic material, not the whole cell, into the site of injury. The finding, published in Nature Neuroscience, challenges long-held assumptions about how limited the adult brain's capacity for self-repair really is.
The study, led by co-first authors Marina Herwerth and Matthias Wyss under the direction of Bruno Weber at UZH's Institute of Pharmacology and Toxicology, used two-photon microscopy to watch the brains of living mice in real time for several weeks after researchers induced small lesions, just under half a millimeter across. By mapping which genes switched on in which cells over that period, the team identified a distinct population of what they call "regenerative" astrocytes, the star-shaped support cells that normally nourish and stabilize neurons.
Rather than migrating whole into the damaged area, as scientists had generally assumed astrocytes do, these cells stayed at the wound's perimeter and instead dispatched the newly formed nuclei of their daughter cells, gliding them long distances through the cell's own extensions directly into the injury site to rebuild the astrocyte network from within.
The findings of our study reveal a previously unknown ability of the adult brain to repair itself.
Bruno Weber, University of Zurich
Toward new treatments
The researchers also catalogued genes and signaling pathways that switch on temporarily during this repair process, which they say could serve as starting points for future therapies. Potential targets include traumatic brain injury and autoimmune conditions such as neuromyelitis optica spectrum disorder, in which the immune system attacks and destroys astrocytes directly.
The work so far is confined to mice, and the team cautions that it remains to be shown whether the same regenerative astrocyte population exists in the human brain, and whether the process could eventually be triggered or enhanced with drugs. Weber's group says further studies are planned to test whether boosting this natural repair mechanism could improve recovery after stroke, injury or disease. If the pathway does translate to humans, researchers say it could eventually offer a way to intervene in the brain's own healing process rather than relying solely on rehabilitation after damage has already occurred.
