Nature: Astrocytes may devour synactical connections to maintain the plasticity of the adult body's brain

January 4, 2021 // -- The developing brain continues to produce new neuron connections, known as synapses, as we learn and remember; important connections (those that are repeatedly introduced, such as how to avoid dangerous connections to the body, etc.) are cultured and strengthened, and connections that are considered unnecessary are removed; and similar trimmings are experienced in the brains of adults, but researchers do not yet know how or why synapses are removed from the adult brain.
recently, scientists from the Korea Institute of Advanced Science and Technology and other institutions revealed the molecular mechanisms of the plasticity of the adult brain and the occurrence of underlying neurological disorders in a study published in the international journal
. Professor Won-Suk Chung, an
researcher, said the study had far-reaching implications for understanding the molecular mechanisms of changes in the brain's neural circuits during learning, memory and even illness, and that changes in the number of synapses were highly correlated with the prevalence of a variety of neurological disorders, such as autism spectrum disorders, schizophrenia, frontal lobe dementia and multiple forms of epilepsy.
photo source: The Korea Advanced Institute of Science and Technology (KAIST) grayscale in the brain contains small glial cells and astrological glial cells that support neuronal and synth functions.
Small glial cells act as a front-line defense cell, primarily responsible for devouring pathogens and dead cells, while astrocytes are astrocytes that help control signals between neurons to promote the construction of brain structures and maintain the body's internal balance;
Researcher Chung said: 'Using new tools, we have found for the first time that astrological glial cells (not small glial cells) can constantly eliminate excessive and unnecessary adult excitable synhapus connections to respond to neuronal activity;
addition, the researchers developed a molecular sensor to detect synapses eliminated by glial cells, while quantifying which types of synapses are eliminated.
researchers also used the technique in mouse models that removed the MEGF10 gene, which helps star-shaped glial cells eliminate synapses.
The number of excitable synapses in their sea mass is often abnormally high, and after a joint study, the researchers found that these increased excitable synapses showed impaired functionality, leading to learning and memory formation defects in the missing animal models of MEGF10.
researchers believe that this process can at least be clarified in the CA1 region of the formative mema, astrogenic glial cells are the main participants in the elimination of synapses, and their function is essential to control the number and plasticity of synapses.
Now that researchers are beginning to understand how synactical elimination affects brain maturation and internal balance, in their preliminary study of brain regions in other models, they found that the synapse elimination rates of star glial cells appear to be different in each region, so they speculate that multiple internal and external factors may influence the circuits of star glial cells to regulate each region.
'Our long-term goal is to understand how synhapus transitions mediated by astrological glial cells affect the onment and progression of a variety of neurological disorders,' said Chung, a researcher at the end of the study, 'and the researchers have come up with an interesting hypothesis that regulating the phagocytosis of astrological glial cells to restore synhapus connectivity may serve as a new strategy to treat multiple human brain disorders.'
() Original source: Lee, JH., Kim, Jy., Noh, S. et al. Astrocytes phagocytose adult hippocampal synapses for circuit homeostasis. Nature (2020). doi：10.1038/s41586-020-03060-3