Scientists have identified a new form of communication in brain cells that involves the direct transfer of proteins between neurons.
Typically, neurons in the brain communicate via chemicals called neurotransmitters that relay signals from one cell to the next. Scientists have long suspected that certain proteins may also move independently across brain cells. For example, the toxic proteins tau that leads to the development of Alzheimer’s disease. However, it has remained unclear whether the trans-neuronal transfer of proteins also takes place in healthy brains. Now, scientists at Scripps Research have found evidence of a new form of cellular communication in the brain involving the transfer of proteins. They published their findings in the journal Cell Reports.
This is an entirely new way that cells in the brain can communicate with one another that has never before been integrated into how we think about health and disease.
Dr Hollis Cline, study author
To confirm their hypothesis, scientists labelled neuronal proteins in rats’ eyes using a tagging molecule called biotin. Since biotin cannot be reintegrated into new proteins if the proteins are disassembled, this particular method allowed the team to only track proteins that stay intact. Eleven days later, scientists observed the presence of biotin in the animals’ visual cortex. This is an area of the brain that processes vision and is quite distant from the retinal cells.
Next, using mass spectroscopy, the researchers identified 200 tagged proteins that had travelled to the visual cortex. Among them were also tau and synuclein proteins. Thus, confirming that these proteins also move across neurons in a healthy brain. However, in disease states such as Alzheimer’s, a toxic form of the protein moves between cells.
Researchers believe that their findings can likely lead to the development of new treatments for neurodegenerative disorders.
Reference:
Schiapparelli, Lucio M., et al. “Proteomic Screen Reveals Diverse Protein Transport between Connected Neurons in the Visual System.” Cell Reports, vol. 38, no. 4, 2022, p. 110287., doi:10.1016/j.celrep.2021.110287.
