Brain Cells Called Astrocytes Have Unexpected Role in Brain ‘Plasticity’
Source: Salk Institute
Summary: A team from the Salk Institute has shown that astrocytes long overlooked supportive cells in the brain help to enable the brain’s plasticity, a new role for astrocytes that was not previously known.
When we’re born, our brains have a great deal of flexibility. Having this flexibility to grow and change gives the immature brain the ability to adapt to new experiences and organize its interconnecting web of neural circuits. As we age, this quality, called “plasticity,” lessens. Astrocytes are important for the development of the brain; however, we knew very little about the role of astrocytes in the adult brain. To investigate this role, we used a lot of techniques in the lab to identify a signal made by astrocytes that’s very important for brain maturation. A team from the Salk Institute has shown that astrocytes long overlooked supportive cells in the brain help to enable the brain’s plasticity, a new role for astrocytes that was not previously known. The findings could point to ways to restore connections that have been lost due to aging or trauma. The study findings were published in the journal Neuron.
The signal turned out to be a protein astrocytes secrete called Chrdl1, which increases the number and maturity of connections between nerve cells, enabling the stabilization of neural connections and circuits once they finish developing. To further understand the role of Chrdl1, the team developed mouse models with the gene disabled by introduced mutations. These mice had a level of plasticity in their brains that was much higher than normal. Adult mice with the Chrdl1 mutation had brain plasticity that looked very much like that of young mice, whose brains are still in the early stages of development. Not much is known about the role of Chrdl1 in humans, but one study of a family with a Chrdl1 mutation showed they performed extremely well in memory tests. Other studies have shown the level of the gene encoding Chrdl1 is altered in schizophrenia and bipolar disorder, suggesting that Chrdl1 may have important roles in both health and disease.
More Information: Elena Blanco-Suarez et al, “Astrocyte-Secreted Chordin-like 1 Drives Synapse Maturation and Limits Plasticity by Increasing Synaptic GluA2 AMPA Receptors”, Neuron (2018). DOI: 10.1016/j.neuron.2018.09.043