Scientists at UCLA have used a molecule found in green tea to identify additional molecules that could break up protein tangles in the brain thought to cause Alzheimer’s and similar diseases.
The green tea molecule, EGCG, is known to break up tau fibers — long, multilayered filaments that form tangles that attack neurons, causing them to die.
In a paper published in Nature Communications, UCLA biochemists describe how EGCG snaps tau fibers layer by layer. They also show how they discovered other molecules likely to work the same way that would make better potential candidates for drugs than EGCG, which can’t easily penetrate the brain. The finding opens up new possibilities for fighting Alzheimer’s, Parkinson’s and related diseases by developing drugs that target the structure of tau fibers and other amyloid fibrils.
Thousands of J-shaped layers of tau molecules bound together make up the type of amyloid fibrils known as tangles, first observed a century ago by Alois Alzheimer in the post-mortem brain of a patient with dementia. These fibers grow and spread throughout the brain, killing neurons and inducing brain atrophy. Many scientists think removing or destroying tau fibers can halt the progression of dementia.
“If we could break up these fibers we may be able to stop death of neurons,” said David Eisenberg, UCLA professor of chemistry and biochemistry whose lab led the new research. “Industry has generally failed at doing this because they mainly used large antibodies that have difficulty getting into the brain. For a couple of decades, scientists have known there’s a molecule in green tea called EGCG that can break up amyloid fibers, and that’s where our work departs from the rest.”
EGCG has been studied extensively but has never worked as a drug for Alzheimer’s because it’s ability to dismantle tau fibers works best in water, and it doesn’t enter cells or the brain easily. Also, as soon as EGCG enters the bloodstream it binds to many proteins besides tau fibers, weakening its efficacy.
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