Found: Important Clue to Development of Alzheimer's
Researchers have discovered a gene signature in healthy brains that echoes the pattern in which Alzheimer’s disease spreads through the brain.
The findings, published in the journal Science Advances, could help uncover the molecular origins of this devastating disease, and may be used to develop preventative treatments for at-risk individuals to be taken well before symptoms appear.
The results, by researchers from the University of Cambridge, identified a specific signature of a group of genes in the regions of the brain that are most vulnerable to Alzheimer’s disease. They found that these parts of the brain are vulnerable because the body’s defense mechanisms against the proteins partly responsible for Alzheimer’s disease are weaker in these areas.
Healthy individuals with this specific gene signature are highly likely to develop Alzheimer’s disease in later life, and would most benefit from preventative treatments, if and when they are developed for human use.
Alzheimer’s disease, the most common form of dementia, is characterized by the progressive degeneration of the brain. Not only is the disease currently incurable, but its molecular origins are still unknown. Degeneration in Alzheimer’s disease follows a characteristic pattern: starting from the entorhinal region and spreading out to all neocortical areas. What researchers have long wondered is why certain parts of the brain are more vulnerable to Alzheimer’s disease than others.
“To answer this question, what we’ve tried to do is to predict disease progression starting from healthy brains,” said senior author Professor Michele Vendruscolo of the Centre for Misfolding Diseases at Cambridge’s Department of Chemistry. “If we can predict where and when neuronal damage will occur, then we will understand why certain brain tissues are vulnerable, and get a glimpse at the molecular origins of Alzheimer’s disease.”
One of the hallmarks of Alzheimer’s disease is the build-up of protein deposits, known as plaques and tangles, in the brains of affected individuals. These deposits, which accumulate when naturally-occurring proteins in the body fold into the wrong shape and stick together, are formed primarily of two proteins: amyloid-beta and tau.
“We wanted to know whether there is something special about the way these proteins behave in vulnerable brain tissue in young individuals, long before the typical age of onset of the disease,” said Vendruscolo.
Vendruscolo and his colleagues found that part of the answer lay within the mechanism of control of amyloid-beta and tau. Through the analysis of more than 500 samples of healthy brain tissues, they identified a signature of a group of genes in healthy brains. When compared with tissue from Alzheimer’s patients, the researchers found that this same pattern is repeated in the way the disease spreads in the brain.