A new research has questioned the role of particular protein – beta amyloid – in development of Alzheimer’s disease suggesting that it could be helpful to human health.
An international team of researchers led by University of Melbourne have found that there is a shorter form of beta amyloid that safely binds copper when in access protecting the brain tissue from damage. The discovery will help researchers better understand the complicated brain chemistry behind dementia and specifically Alzheimer’s disease, a condition that affects millions of people around the world.
Researchers have been intensely interested in the role of beta-amyloid in the development of Alzheimer’s disease. This is because clumps of the protein are formed in brains of people with the illness.
In the late 1990s, high levels of copper were discovered within these clumps. Copper is essential to health, but too much can produce harmful free radicals. Many scientists began to suspect that this copper might be contributing to the disease. They found that beta-amyloid can bind to copper indiscriminately and allow it to produce these damaging free radicals.
Dr Simon Drew at the University of Melbourne and Prof Wojciech Bal at the Polish Academy of Sciences, carried out closer analysis of beta amyloid protein and found that they are of different sizes. A good proportion of beta amyloid is missing the first three links at the start of the protein’s chain-like structure.
Researchers say that this short form of beta amyloid has been overlooked by most researchers since the composition of beta amyloid was first identified 30 years ago. They add that the shorter form of beta amyloid is present in the diseased brain, but now with the latest findings it is clear that it is abundant in healthy brains as well.
“The small change in length makes a huge difference to its copper binding properties. We found that the short form of the protein is capable of binding copper at least 1000 times stronger than the longer forms. It also wraps around the metal in a way that prevents it from producing free radicals”, Dr Dew explains.
Owing to the amount of beta amyloid present in the brain, researchers speculate that this type of beta amyloid is protective.
“It’s very different from the current view of how beta amyloid interacts with biological copper.”
So far, therapies aimed at lowering the production of beta amyloid have shown only a modest ability to slow cognitive decline and the number of people affected by the Alzheimer’s disease continues to grow.
Dr Drew and the team from Poland are now working to develop a method for identifying the copper-bound form of the short beta amyloid in the body.
This will enable them to screen how much copper it holds in the brain, whether it safely escorts the copper from one place to another, and how this may change in ageing and disease.
“If a beneficial role in copper balance can be established, it’s still possible to have too much of a good thing,” Dr Drew said.
“As the amount of beta amyloid in the brain increases during Alzheimer’s disease, the shorter form can also clump together and this may interfere with its normal function. Higher levels of the short form may further enable it to soak up copper from other places where it is needed. It could be a Jekyll and Hyde scenario.”
