Astrocytes represent a very important structural contingent of our brain, about ten times more numerous than that formed by neurons. While far less well known than neurons, these stellate cells are no less important from a functional perspective.

A new study coordinated by Paola Bezzi of the Department of Physiology and Pharmacology "Vittorio Erspamer" of Sapienza University of Rome, carried out together with researchers from the Universities of Lausanne and Zurich, highlights how the growth and maturation of stellate cells immediately after birth is critical for the survival of neurons and therefore for the proper formation and function of nerve circuits in the adult brain. The paper has been published in the journal Cell Reports.

Brain function is based on the activity of nerve circuits and the processes of signal transmission between neurons, which occurs in tiny structures called synapses. Just after birth, during the lactation period, neurons are still immature, and synapses are still being formed. However, to date, there has been limited knowledge about the development and role of stellate cells in neonatal brain development processes.

Researchers have developed a new methodological approach based on the injection of fluorescent dyes that can provide a more detailed view of the structural organization of astrocytes.

The study showed that the functionality of neuronal circuits and synapses depends on the proper development of stellate cells that have a particularly developed energy reserve during the neonatal period.

"We found that among the various functions of these cells, there is one that is fundamental for the functioning of neurons: the production of energy, " says Paola Bezzi of Sapienza. "Astrocytes are real 'baby-sitters' of developing neurons and use a lot of energy to perform this fundamental role. Using recently developed genetic techniques, combined with single-cell staining, we have shown that if the organelles responsible for energy production (the mitochondria) are not functioning properly, the stellate cells do not develop, do not take care of the neurons and thus induce problems in the formation and maturation of nerve cells and synapses."  

"In neuroscience, the astrocyte currently represents one of the most exciting topics as research on perinatal brain maturation forms the basis for understanding related diseases."

The results obtained by the researchers allow them to investigate the cellular and molecular mechanisms of several psychiatric diseases that occur in the perinatal period and mainly affect the maturation of nerve circuits, such as autism, schizophrenia or attention deficit, and thus to identify new potential drugs.

References:

Mitochondrial biogenesis in developing astrocytes regulates astrocyte maturation and synapse formation - Tamara Zehnder, Francesco Petrelli, Jennifer Romanos, Franck Polleux, Mirko Santello, Paola Bezzi - Cell Reports 2021 https://doi.org/10.1016/j.celrep.2021.108952

Further Information

Paola Bezzi
Department of Physiology and Pharmacology "Vittorio Erspamer"
paola.bezzi@uniroma1.it