Researchers from King's College London have discovered that neuronal activity can stimulate tau release from healthy neurons in the absence of cell death. The results published by Diane Hanger and her colleagues in EMBO reports show that treatment of neurons with known biological signaling molecules increases the release of tau into the culture medi-um. The release of tau from cortical neurons is therefore a physiological process that can be regulated by neuronal activity.
Tau proteins stabilize microtubules, the long threads of polymers that help to maintain the structure of the cell. However, in Alzheimer's disease or certain types of dementia, tau accumulates in neurons or glial cells, where it contributes to neurodegeneration.
In addition to intracellular aggregation, recent experiments have shown that tau is released from neuronal cells and taken up by neighboring cells, which allows the spread of aggregated tau across the brain. This release could occur passive-ly from dying neuronal cells, though some evidence suggests it might take place before neuronal cell death and neurodegeneration. The new findings indicate that tau release is an active process in healthy neurons and this could be altered in diseased brains.