Newly Discovered Brain Cells Bridge Neurons and Glial Cells

A research team from the University of Lausanne (UNIL) and the Wyss Center has uncovered a novel class of brain cells that plays a pivotal role in brain function. 

These cells, possessing hybrid characteristics between neurons and glial cells, are found in various brain regions in mice and humans, offering unique insights into memory, motor control, and the prevention of epileptic seizures.

Redefining Brain Cell Families

Traditionally, the brain was believed to operate primarily through neurons, which rapidly process and transmit information across neural networks. Complementing their role, glial cells perform vital structural, energetic, and immune functions while maintaining physiological stability.

 A subset of glial cells, known as astrocytes, closely envelop synapses, where neurotransmitters facilitate information transfer between neurons. This proximity led scientists to speculate about the active involvement of astrocytes in synaptic transmission and information processing, though conclusive evidence remained elusive.

Researchers from UNIL’s Department of Basic Neurosciences and the Wyss Center for Bio and Neuroengineering in Geneva have finally ended this longstanding debate by identifying a new type of cell that possesses astrocytic features and expresses the molecular machinery required for synaptic transmission. This discovery clarifies the role of astrocytes in synaptic activity.

Unraveling the Mystery: A Functional Role

To confirm whether astrocytes can release neurotransmitters akin to neurons, the research team delved into the molecular content of astrocytes using cutting-edge molecular biology techniques. 

They discovered traces of vesicular proteins like VGLUT, responsible for filling neuronal vesicles dedicated to glutamate release—an essential neurotransmitter. These specialized proteins in astrocytes enable rapid communication with neighboring cells.

Functional Impact

The researchers examined if these hybrid cells were functionally capable of releasing glutamate at speeds comparable to synaptic transmission. They used advanced imaging techniques to visualize glutamate release from vesicles within brain tissues and live mice. 

Specific astrocytes responded to selective stimuli with rapid glutamate release, affecting synaptic transmission and regulating neuronal circuits. Suppressing VGLUT expression in these hybrid cells revealed their role in modulating neuronal activity, influencing communication levels and neuronal excitation.

Implications for Brain Pathologies

This discovery carries significant implications for brain disorders. Disrupting glutamatergic astrocytes not only impairs memory consolidation, affecting long-term potentiation, a process essential for memorization but also exacerbates epilepsy seizures.

Moreover, these cells influence brain circuits related to motor control, offering potential therapeutic targets for conditions like Parkinson’s disease.

This groundbreaking finding introduces a new category of cells bridging the gap between neurons and astrocytes, ushering in a new era of research opportunities. Future investigations will explore their potential protective role against memory impairment in Alzheimer’s disease and their involvement in other brain regions and pathologies beyond the scope of this study.

Read the original article on Medical Xpress.

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