University of Zurich researchers have identified a subset of astrocytes that helped rebuild astrocyte-depleted areas in the brains of living mice by moving newly formed daughter-cell nuclei along elongated cellular processes.
Astrocytes are star-shaped glial cells that support neurons. They supply nutrients, help regulate blood flow and maintain healthy brain tissue. Astrocyte loss can occur after certain brain injuries and in conditions such as neuromyelitis optica spectrum disorder, or NMOSD, an autoimmune disease in which antibodies target these cells.
Tracking repair in living mice
The team, led by Bruno Weber at UZH’s Institute of Pharmacology and Toxicology, created small, localized areas of astrocyte loss in the somatosensory cortex of adult mice using aquaporin-4 antibody-mediated ablation. The model was designed to reproduce a form of astrocyte damage relevant to NMOSD.
Using two-photon microscopy, the researchers observed the animals’ brains over several weeks. They combined this imaging with spatial transcriptomic profiling to identify molecular changes occurring around the astrocyte-depleted areas.
The researchers identified what they describe as “regenerative” astrocytes at the edges of the lesions. These cells divided, temporarily entered states containing multiple nuclei and extended cellular processes toward the depleted area.
Newly formed daughter-cell nuclei then gradually moved through the shared cellular material and into previously unoccupied astrocyte territories. This helped restore the local astrocyte network without requiring entire cells to migrate across the lesion.
An image released by UZH shows a lesion measuring just under 0.5 millimetres across. Regenerative astrocytes surround its edge, while newly formed nuclei move along cellular extensions toward the astrocyte-depleted area.
Weber said the process allowed the cells to move daughter-cell nuclei across relatively long distances and knit the local astrocyte network back together.
What the result means—and what it does not
According to UZH, the finding challenges the assumption that adult brain tissue cannot fully replace astrocytes after localized loss. It reveals a previously unknown mechanism through which astrocyte networks can be rebuilt after certain forms of damage in mice.
The result does not show that the brain can regenerate all types of damaged cells. It also does not demonstrate that neurons were replaced or that the same repair mechanism occurs after major traumatic brain injuries, strokes or widespread neurodegenerative disease.
Most importantly, this is not a demonstrated treatment for people. The experiments were conducted in adult mice with spatially confined astrocyte loss, and further research is required to determine whether a comparable process occurs in the human brain.
The researchers identified genes and signalling pathways that were temporarily activated while the astrocyte network was being restored. Weber said these molecular pathways could eventually offer starting points for research into ways of supporting regeneration after diseases or injuries involving astrocyte loss.
Co-lead authors Marina Herwerth and Matthias T. Wyss reported the study, Focal astrocyte loss reveals nuclear translocation during lesion repopulation, in Nature Neuroscience. The peer-reviewed paper was published on July 23, 2026, and the University of Zurich released its summary on August 10, 2026.