Scientists discover protein that helps Alzheimer's spread in the brain

Researchers at the University of Utah Health and Washington University in St. Louis have identified a brain protein that plays a key role in the spread of Alzheimer's disease. The protein, called Arc, normally helps neurons communicate by packaging signals into tiny vesicles that travel between cells. However, the study in mice shows that toxic Tau protein can hijack this system, hitching a ride inside Arc-containing vesicles to infect healthy neurons.

The experiments compared mouse models of Alzheimer's with and without the Arc protein. Without Arc, the transfer of toxic Tau between neurons was drastically reduced, almost stopping entirely. This suggests that Arc is essential for the spread of the disease. However, the researchers also found that Arc has a protective function in early stages: it helps diseased cells expel excess Tau, allowing them to survive longer. When Arc was absent, Tau accumulated inside cells, killing them faster.

The findings were published in the journal Cell. The team also detected vesicles containing both Arc and Tau in human brain tissue, indicating a similar mechanism may exist in people. While cautioning that much more research is needed, the scientists believe that future therapies could target these vesicles to prevent toxic Tau from entering healthy cells, potentially slowing cognitive decline in Alzheimer's patients.