A new source for the generation of nerve cells in the brain has been discovered by scientists.
Professor Magdalena Gotz of Helmholtz Zentrum Munchen and Ludwig-Maximilians-Universitat (LMU) Munich and colleagues have discovered progenitor cells, which can form new glutamatergic neurons following injury to the cerebral cortex.
Particularly in Alzheimer's disease, nerve cell degeneration plays a crucial role. In the future, new therapeutic options may possibly be derived from steering the generation and/or migration mechanism, according to the researchers.
Until only a few years ago, neurogenesis - the process of nerve cell development - was considered to be impossible in the adult brain.
Then researchers discovered regions in the forebrain in humans in which new nerve cells can be generated throughout life. These so-called GABAergic cells use gamma-aminobutyric acid (GABA), a neurotransmitter of the central nervous system.
Now, the research team, led by Gotz, has taken a closer look at this brain region in the mouse model. They found that even in the forebrain, there are other nerve cells that are regularly generated - the so-called glutamatergic nerve cells, which use glutamate as neurotransmitter.
The stem cell researchers could prove this by means of a specific transcription factor: Tbr2 is only present in progenitor cells of glutamatergic nerve cells.
The newly generated nerve cells in the adult organism are located in the olfactory bulb, the region of the brain involved in the sense of smell. Nerve cells that use glutamate as a neurotransmitter are also responsible for memory - storing and retrieving information.
In Alzheimer dementia, alterations in the signal transduction pathways of these special cells play a significant role.
Gotz explained the importance of the new finding, saying "Neural progenitor cells can generate these newly discovered glutamatergic nerve cells for the neighbouring cerebral cortex - for example after brain injury."
The research group was able to show this on the mouse model. There the cells migrated into the damaged neighbouring cerebrum tissue and generated mature neurons. Accordingly, progenitor cells could then replace degenerate nerve cells.
"Now it will be interesting to find out whether this process also takes place in humans, particularly in Alzheimer's patients and also whether the process can be kept under control to avoid massive cell death," Gotz said.
The findings of the study have been published in the current issue of the renowned journal Nature Neuroscience.