Study suggests brain protein Arc may help spread Alzheimer’s toxic Tau
8 reported1 unconfirmed
Researchers at University of Utah Health have identified a brain protein called Arc that may help toxic Tau proteins spread between neurons in Alzheimer's disease, according to a study published in Cell. In experiments with mice, the team found that Arc, which normally helps neurons communicate, can carry toxic Tau inside tiny membrane-bound sacs called extracellular vesicles from damaged neurons to healthy ones. When Arc was removed from the mice, the transfer of Tau was "severely, severely reduced" and "almost gone," said first author Mitali Tyagi. However, the protein also appears to play a protective role early in disease by helping damaged cells expel excess Tau, allowing them to survive longer. The researchers also found extracellular vesicles containing both Arc and Tau in human brain tissue, suggesting a similar mechanism could exist in people, but senior author Jason Shepherd stressed that most work has been in mice and "we're far away from saying that we're developing a treatment for anything."
What’s reported
Alzheimer's disease involves buildup of toxic Tau protein that damages and kills brain cells.
The study found that the brain protein Arc helps toxic Tau spread from diseased neurons to healthy ones in mice.
Arc normally packages itself inside extracellular vesicles that travel between neurons carrying cellular signals.
Toxic Tau attaches to Arc inside these vesicles to travel from unhealthy to healthy neurons.
In mice without Arc, extracellular vesicles contained very little Tau and disease spread was severely reduced.
Arc also helps damaged neurons expel excess toxic Tau, allowing them to survive longer; without Arc, Tau became trapped and neurons died more quickly.
The researchers found extracellular vesicles containing both Arc and Tau in human brain tissue.
The study was published in the journal Cell on June 30, 2026.
Open questions
Whether the same mechanism exists in humans, as most work has been in mice.
Key figures
Jason Shepherd, PhD, professor of neurobiology at University of Utah Health and senior author of the study
Mitali Tyagi, PhD, postdoctoral research associate at Washington University in St. Louis and first author of the study
Sources: ScienceDaily
