How a Brain Sickness Spreads to Healthy Cells

Alzheimer's disease destroys many brain cells over time. This terrible sickness causes memory loss because a toxic protein accumulates. The name of this bad protein is Tau. In healthy brains, Tau does not cause problems.

But in sick brains, Tau forms large tangles. Dr. Mitali Tyagi is a researcher at Washington University. She compares these sticky tangles to glue monsters. They block the transport system of the cell and kill it.

Recently, scientists at University of Utah Health made a new discovery. They studied the disease in mice during their tests. They found a brain protein and the name is Arc. Usually, Arc helps the brain because it sends signals between neurons.

Arc packages itself inside tiny sacs in the brain. The scientific name for these sacs is extracellular vesicles. But toxic Tau uses these same sacs to travel. Tau attaches to Arc and goes to healthy neurons.

Then, the bad Tau corrupts the healthy cells. The researchers compared mice with Arc and mice without Arc. They saw a big difference during their tests. In mice without Arc, the transfer of Tau stopped.

According to Dr. Tyagi, the transfer was almost gone. But Arc also protects the sick cells during the disease. It helps neurons release the toxic Tau into the brain. Without Arc, Tau accumulates and the sick neurons die much faster.

So, blocking Arc is not a good treatment. Instead, future medicines will stop the toxic sacs. They will block them before they enter healthy cells. The team also found these sacs in human brain tissue.

Dr. Jason Shepherd is a neurobiology professor at Utah. He believes this discovery will open new ways to treat patients. But they must do much more research on humans first. The team published their study in the journal Cell.