Scientists identify mechanism that could contribute to problems in Alzheimer's

April 26, 2012

Scientists at the Gladstone Institutes have unraveled a process by which depletion of a specific protein in the brain contributes to the memory problems associated with Alzheimer's disease. These findings provide new insights into the disease's development and may lead to new therapies that could benefit the millions of people worldwide suffering from Alzheimer's and other devastating neurological disorders.

The study, led by Gladstone Investigator Jorge J. Palop, PhD, revealed that low levels of a protein, called Nav1.1, disrupt the electrical activity between . Such activity is crucial for healthy and memory. Indeed, the researchers found that restoring Nav1.1 levels in mice that were genetically modified to mimic key aspects of Alzheimer's disease (AD-mice) improved learning and and increased their lifespan. They report their findings in the April 27 issue of Cell, available online today.

"It is estimated that more than 30 million people worldwide suffer from Alzheimer's disease and that number is expected to rise dramatically in the near future," said Lennart Mucke, MD, who directs at Gladstone, an independent and nonprofit biomedical-research organization. "This research improves our understanding of the biological processes that underlie in this disease and could open the door for new therapeutic interventions."

The researchers' findings suggest that Nav1.1 levels in special regulatory called parvalbumin cells, or , are essential to generate healthy brain-wave activity—and that problems in this process contribute to cognitive decline in AD-mice and possibly in patients with Alzheimer's.

In the brain, neurons form highly interconnected networks, using chemical and electrical signals to communicate with each other. The researchers investigated whether this communication between neurons is disrupted in AD-mice, and if so, how this may affect the symptoms of Alzheimer's disease.

To study this, they performed electroencephalogram (EEG) recordings—a technique that detects abnormalities in the brain's electrical waves such as those found in patients with epilepsy. They found that similar abnormalities emerged during periods of reduced gamma-wave oscillations—a type of brain wave that is crucial to regulating .

"Like a conductor in an orchestra, PV cells regulate brain rhythms by precisely controlling excitatory brain activity," said Laure Verret, PhD, postdoctoral fellow and lead author. "We found that PV cells in patients with Alzheimer's and in AD-mice have low levels of the protein Nav1.1—likely contributing to PV cell dysfunction. As a consequence, AD-mice had abnormal brain rhythms. By restoring Nav1.1 levels, we were able to re-establish normal brain function."

Indeed, the scientists found that increasing Nav1.1 levels in PV cells improves brain wave activity, learning, memory and survival rates in AD-mice.

"Enhancing Nav1.1 activity, and consequently improving PV cell function, may help in the treatment of Alzheimer's disease and other neurological disorders associated with gamma-wave alterations and cognitive impairments such as epilepsy, autism and schizophrenia," said Dr. Palop, who is also an assistant professor of neurology at the University of California, San Francisco, with which Gladstone is affiliated. "These findings may allow us to develop therapies to help patients with these devastating diseases."

Related Stories

Recommended for you

Dementia with Lewy bodies: Unique genetic profile identified

December 15, 2017
Dementia with Lewy bodies has a unique genetic profile, distinct from those of Alzheimer's disease or Parkinson's disease, according to the first large-scale genetic study of this common type of dementia.

Major cause of dementia discovered

December 11, 2017
An international team of scientists have confirmed the discovery of a major cause of dementia, with important implications for possible treatment and diagnosis.

Canola oil linked to worsened memory and learning ability in Alzheimer's

December 7, 2017
Canola oil is one of the most widely consumed vegetable oils in the world, yet surprisingly little is known about its effects on health. Now, a new study published online December 7 in the journal Scientific Reports by researchers ...

Genetics study suggests that education reduces risk of Alzheimer's disease

December 7, 2017
The theory that education protects against Alzheimer's disease has been given further weight by new research from the University of Cambridge, funded by the European Union. The study is published today in the BMJ.

Healthy mitochondria could stop Alzheimer's

December 6, 2017
Alzheimer's disease is the most common form of dementia and neurodegeneration worldwide. A major hallmark of the disease is the accumulation of toxic plaques in the brain, formed by the abnormal aggregation of a protein called ...

Alzheimer's damage in mice reduced with compound that targets APOE gene

December 6, 2017
People who carry the APOE4 genetic variant face a substantial risk for developing Alzheimer's disease.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.