Alzheimer's: How does tau disrupt brain cells?
Scientists have found a previously unknown mechanism in which the protein tau, which is implicated in Alzheimer's disease, damages brain cells by interfering with their internal communications.
The discovery sheds new light on the origins of this most common cause of dementia, a hallmark of which is the buildup of tangled tau protein filaments in the brain.
The finding could also lead to new treatments for Alzheimer's and other diseases that progressively destroy brain tissue, conclude the researchers in a paper about their work that now features in the journal Neuron.
Scientists from Massachusetts General Hospital (MGH) in Charlestown and the Johns Hopkins School of Medicine in Baltimore, MD, led the study, which set out to investigate how tau protein might contribute to brain cell damage.
Alzheimer's disease does not go away and gets worse over time. It is the sixth most common cause of death in adults in the United States, where an estimated 5.7 million people have the disease.
Exact causes of Alzheimer's still unknown
Exactly what causes Alzheimer's and other forms of dementia is still a mystery to science. Evidence suggests that a combination of environment, genes, and lifestyle is involved, with different factors having different amounts of influence in different people.
Most cases of Alzheimer's do not show symptoms until people are in their 60s and older. The risk of getting the disease rises rapidly with age after this.
Brain studies of people with the disease — together with postmortem analyses of brain tissue — have revealed much about how Alzheimer's changes and harms the brain.
"Age-related changes" include: inflammation; shrinkage in some brain regions; creation of unstable, short-lived molecules known as free radicals; and disruption of cellular energy production.
The brain of a person with Alzheimer's disease also has two distinguishing features: plaques of amyloid protein that form between cells, and tangles of tau protein that form inside cells. The recent study concerns the latter.
