Immune Proteins Regulate Brain-cell Connections

Researchers from Princeton University and the University of California-San Diego (UCSD), recently found that an immune-system protein called MHCI, moonlights in the nervous system to help regulate the number of synapses. The research, published in the Journal of Neuroscience, reported that in the brain, MHCI could play an unexpected role in conditions such as Alzheimer’s disease, type II diabetes and autism. MHCI proteins are known for their role in the immune system, where they present protein fragments from pathogens and cancerous cells to T cells, which are white blood cells that play a central role in the body’s response to infection. This allows T cells to recognize and kill infected, cancerous cells. In the brain, however, the researchers found that the MHCI immune molecules are one of the only known factors that limit the density of synapses, ensuring that synapses form in the appropriate numbers necessary to support healthy brain function. MHCI limited synapse density by inhibiting insulin receptors, which regulate the body’s sugar metabolism and, in the brain, promote synapse function. To read more about this study, click here.