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

Noninvasive eye scan could detect key signs of Alzheimer's years before patients show symptoms

August 17, 2017
Cedars-Sinai neuroscience investigators have found that Alzheimer's disease affects the retina—the back of the eye—similarly to the way it affects the brain. The study also revealed that an investigational, noninvasive ...

Could olfactory loss point to Alzheimer's disease?

August 16, 2017
By the time you start losing your memory, it's almost too late. That's because the damage to your brain associated with Alzheimer's disease (AD) may already have been going on for as long as twenty years. Which is why there ...

New Machine Learning program shows promise for early Alzheimer's diagnosis

August 15, 2017
A new machine learning program developed by researchers at Case Western Reserve University appears to outperform other methods for diagnosing Alzheimer's disease before symptoms begin to interfere with every day living, initial ...

Brain scan study adds to evidence that lower brain serotonin levels are linked to dementia

August 14, 2017
In a study looking at brain scans of people with mild loss of thought and memory ability, Johns Hopkins researchers report evidence of lower levels of the serotonin transporter—a natural brain chemical that regulates mood, ...

Alzheimer's risk linked to energy shortage in brain's immune cells

August 14, 2017
People with specific mutations in the gene TREM2 are three times more likely to develop Alzheimer's disease than those who carry more common variants of the gene. But until now, scientists had no explanation for the link.

Scientists reveal role for lysosome transport in Alzheimer's disease progression

August 7, 2017
Researchers from Yale University School of Medicine have discovered that defects in the transport of lysosomes within neurons promote the buildup of protein aggregates in the brains of mice with Alzheimer's disease. The study, ...

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.