In this study Magdalena Götz and her team showed how astroglia can be directly converted into the two main classes of cortical neurons. This was made possible by the selective transduction of specific proteins - transcription factors - which regulate the transcription of DNA. While the transcription factor neurogenin-2 directs the generation of excitatory neurons, the same astroglial cells yield inhibitory neurons after transduction of the transcription factor Dlx2.

Neurons are the cells in the brain which transmit information, while the astroglia (star-shaped glial cells) serve as a supportive scaffold and are involved in metabolism. Moreover, they are closely related to radial glial cells, which during embryonic forebrain development function as precursors for most neurons. In fact, some glial cells even in the adult brain retain the capability of producing neurons - however these are only found in specific regions.

It is still not known exactly what differentiates normal astroglia from radial glial cells with neurogenic potential. However, the researchers led by Magdalena Götz, director of the Institute of Stem Cell Research at Helmholtz Zentrum München and chair of Physiological Genomics at LMU, have already shown in previous studies that astroglia from the cerebral cortex of young mice, which are normally incapable of generating neurons, can be driven to convert into neurons by transducing special regulatory proteins.

"In this study we have succeeded in reprogramming the newly created neurons to the extent that they can now develop functioning synapses. These release - depending on the transcription factor used - either excitatory or inhibitory neurotransmitter substances," said Dr. Benedikt Berninger, lead author of the study. This process could not only be observed in young astroglia, but even in astroglia in the adult brain following tissue injury-induced reactivation. "Our findings nurture the hope that the barrier separating the astroglial and neuronal cells - closely related as they are - is not insurmountable," Dr. Berninger emphasized. Due to these encouraging results, the researchers intend to pursue this avenue further to gain new neurons from the glial cells present in the brain, in order to find therapies for neurodegenerative diseases such as Alzheimer's.

Original Publication: Christophe Heinrich, Robert Blum, Sergio Gascón, Giacomo Masserdotti, Pratibha Tripathi, Rodrigo Sánchez, Steffen Tiedt, Timm Schroeder, Magdalena Götz, Benedikt Berninger. (2010): Directing Astroglia from the Cerebral Cortex into Subtype Specific Functional Neurons. PLoS Biol 8 (5): e1000373. (doi:10.1371/journal.pbio.1000373)

About Helmholtz Zentrum München
Helmholtz Zentrum München is the German Research Center for Environmental Health. As leading center oriented toward Environmental Health, it focuses on chronic and complex diseases which develop from the interaction of environmental factors and individual genetic disposition. Helmholtz Zentrum München has around 1700 staff members. The head office of the center is located in Neuherberg to the north of Munich on a 50-hectare research campus. Helmholtz Zentrum München belongs to the Helmholtz Association, Germany's largest research organization, a community of 16 scientific-technical and medical-biological research centers with a total of 26,500 staff members.