Published: 10-10-2014 09:00 | Updated: 10-10-2014 15:28

Astrocytes repair the brain after stroke

A previously unknown mechanism, through which astrocytes in the brain produce new nerve cells after a stroke, has been discovered by researchers at Karolinska Institutet and Lund University. The findings are published in the journal Science.

A stroke is caused by a blood clot blocking a blood vessel in the brain, which leads to an interruption of blood flow and therefore a shortage of oxygen. Many nerve cells die, resulting in motor, sensory and cognitive problems.

The researchers have shown that following an induced stroke in mice, support cells, so-called astrocytes, start to form nerve cells in the injured part of the brain. Using genetic methods to map the fate of the cells, researchers for the first time could demonstrate that astrocytes in this area formed immature nerve cells, which then developed into mature nerve cells.

Signalling mechanism

The team could also identify the signalling mechanism that regulates the conversion of the astrocytes to nerve cells. In a healthy brain, this signalling mechanism is active and inhibits the conversion and, consequently, the astrocytes do not generate nerve cells. Following a stroke, the signalling mechanism is suppressed and astrocytes can start the process of generating new cells.

Principal Investigator of this study has been Jonas Frisén, professor at the Department of Cell and Molecular Biology, Karolinska Institutet. First study-author is Jens Magnusson, a doctoral student in Jonas Frisén’s lab. The work supported by grants from amongst others the Swedish Research Council, the Swedish Cancer Society, Tobias Foundation, The Swedish Heart and Lung Foundation, Karolinska Institutet StratRegen, the European Union project TargetBraIn, Torsten Söderberg’s Foundation, and Knut och Alice Wallenberg’s Foundation.


A latent neurogenic program in astrocytes regulated by Notch signaling in the mouse
Magnusson JP, Göritz C, Tatarishvili J, Dias DO, Smith EMK, Lindvall O, Kokaia Z, Frisén J.
Science online 10 October 2014