The adult brain may have a greater ability to repair itself after injury and autoimmune disease than scientists once believed. Researchers at the University of Zurich have discovered in mouse experiments that specialized support cells can regenerate damaged brain tissue through an unexpected process. Rather than moving an entire newly formed cell to the injured area, these cells transport newly generated cell nuclei into the damaged region.
Glial cells provide essential support and nourishment throughout the brain. Astrocytes, a star-shaped type of glial cell, are especially important for maintaining healthy neuron function. They supply nutrients to nerve cells, help regulate blood flow, and protect the overall health of brain tissue.
Scientists have traditionally believed that the adult brain cannot fully replace astrocytes after they are destroyed. Astrocyte loss can occur following brain injury or in autoimmune conditions such as neuromyelitis optica spectrum disorder, a rare disease in which the body’s antibodies attack and destroy these vital support cells.
Specialized astrocytes can regenerate damaged brain tissue
The study, led by co-lead authors Marina Herwerth and Matthias Wyss of the Institute of Pharmacology and Toxicology at the University of Zurich, challenges this long-standing view. A research team led by Bruno Weber identified a specialized population of “regenerating” astrocytes in the brains of living mice.
These regenerative astrocytes gather around the edges of injured brain regions and help restore damaged astrocyte networks. “Our findings reveal a previously unknown self-repair capacity of the adult brain. They point to new ways to support recovery from diseases that involve astrocyte loss,” Weber says.
New cell nuclei travel into damaged brain regions
To observe how brain repair occurs, the researchers used two-photon microscopy to monitor the brains of living mice in real time over several weeks. They also analyzed which genes were activated in different parts of the brain. By combining live imaging with gene-activity analysis, the researchers identified the astrocytes responsible for regenerating damaged tissue.
These regenerative cells do more than divide. They also use an unusual process in which newly formed nuclei from daughter cells travel significant distances toward the injured area through astrocyte extensions. As Weber explains, “They glide the newly formed nuclei of their daughter cells across long distances, repopulate the damaged areas of the brain, and reweave the astrocyte network.”
A potential new target for brain regeneration
The discovery that cell nuclei can move through the long extensions of adult astrocytes and into injured tissue provides new insight into how the brain repairs itself after certain types of damage.
If scientists can learn how to selectively activate these natural repair mechanisms, they may be able to improve the regeneration of damaged brain tissue, restore astrocyte networks, and support recovery from neurological disorders involving astrocyte loss.
The research team also identified several genes and signaling pathways that become temporarily active during the brain repair process. These biological signals could become potential targets for future treatments designed to promote regeneration after brain injury or autoimmune disease.
“We were able to identify a large number of genes and signaling pathways that are temporarily activated during repair, which in the future may serve as a starting point to influence regenerative processes after disease or injury,” Weber emphasizes.
Source: www.sciencedaily.com