Problem proteins in Alzheimer's

Mar 02, 2011 By Jonathan Wood

(PhysOrg.com) -- In Alzheimer's disease, two proteins are known to accumulate and build up in the brain. One protein called amyloid β aggregates into large disruptive ‘plaques’, while tau protein forms tangled fibres within nerve cells.

Research has tended to focus on amyloid β, since small numbers of these proteins bound together are known to be toxic to the neurons in the .

But there is some evidence to suggest tau may also be involved in the processes which eventually lead to the memory problems and cognitive decline seen in Alzheimer’s.

Researchers at Oxford University have used a sensitive laboratory model of learning and memory to investigate any connection between amyloid β and tau. They found that tau is absolutely required for amyloid β to disrupt the function of the mouse nerve cells in the lab model. The results were published last month in the Journal of Neuroscience</i>.

"This is one of the first investigations of the mechanisms linking amyloid β and tau that is relevant to the early stages of Alzheimer’s disease," says Dr. Mariana Vargas-Caballero of the Department of Physiology, Anatomy and Genetics, who led the work.

Mariana and colleagues looked at the strengthening of connections between mouse neurons in a dish, since the strengthening of connections in the brain’s neural circuits is thought to be how memories are formed and consolidated.

They found that amyloid β impairs the strengthening of the neural connections, or ‘synaptic plasticity’, although the remained healthy in all other aspects that they could measure. But crucially, in neurons from mice engineered to have no , the amyloid β had no effect on this cellular model of memory.

"This came as a complete surprise. It is a strong and reproducible effect," says Olivia Shipton of the Department of Physiology, Anatomy and Genetics, who is first author on the paper.

The team then went on to show that blocking the activity of tau using a specific chemical inhibitor also prevented the detrimental effects of amyloid β on the mouse neurons.

While it might be tempting to leap to the conclusion that this inhibitor could offer a promising avenue for the development of drugs to slow or halt Alzheimer’s onset, Mariana is more cautious. She says the stage the research is at is more about understanding the disease processes of early Alzheimer’s.

"We want to know how amyloid β can lead to impaired synaptic plasticity as we can assume that this is like what happens in early Alzheimer’s disease. The findings should help us unravel the mechanism involved," she explains.

"There is a huge gap in understanding what is relevant to the situation in humans. But we do now have a sensitive system to study what links amyloid β and tau, and tau and dysfunction in neural connections.

"It is possible that pinpointing where in the chain of events tau is located could allow people in time to develop drug candidates to slow or stop the disruption of neural connections," she adds, but believes that more research is required to first understand the molecular pathways involving tau.

Explore further: Clot dissolver tPA's tardy twin could aid in stroke recovery

More information: www.jneurosci.org/cgi/content/abstract/31/5/1688

add to favorites email to friend print save as pdf

Related Stories

New target identified for Alzheimer’s disease

Sep 29, 2010

Neurological researchers at Rush University Medical Center have found a new therapeutic target that can potentially lead to a new way to prevent the progression of Alzheimer’s disease. The target called neutral sphingomyelinase ...

Scientists identify a new target for Alzheimer's disease

Sep 21, 2010

Neurological researchers at Rush University Medical Center have found a new therapeutic target that can potentially lead to a new way to prevent the progression of Alzheimer's disease. The target called neutral sphingomyelinase ...

Amyloid beta protein gets bum rap

Nov 09, 2009

While too much amyloid beta protein in the brain is linked to the development of Alzheimer's disease, not enough of the protein in healthy brains can cause learning problems and forgetfulness, Saint Louis University scientists ...

Scientists find new cause of Alzheimer's

Apr 19, 2006

Belgium researchers say they are the first to demonstrate the quantity of amyloid protein in brain cells is a major factor of Alzheimer's disease.

Recommended for you

New ALS associated gene identified using innovative strategy

1 hour ago

Using an innovative exome sequencing strategy, a team of international scientists led by John Landers, PhD, at the University of Massachusetts Medical School has shown that TUBA4A, the gene encoding the Tubulin Alpha 4A protein, ...

Can bariatric surgery lead to severe headache?

1 hour ago

Bariatric surgery may be a risk factor for a condition that causes severe headaches, according to a study published in the October 22, 2014, online issue of Neurology, the medical journal of the American Academy of Neurol ...

Bipolar disorder discovery at the nano level

2 hours ago

A nano-sized discovery by Northwestern Medicine scientists helps explain how bipolar disorder affects the brain and could one day lead to new drug therapies to treat the mental illness.

Brain simulation raises questions

5 hours ago

What does it mean to simulate the human brain? Why is it important to do so? And is it even possible to simulate the brain separately from the body it exists in? These questions are discussed in a new paper ...

Human skin cells reprogrammed directly into brain cells

5 hours ago

Scientists have described a way to convert human skin cells directly into a specific type of brain cell affected by Huntington's disease, an ultimately fatal neurodegenerative disorder. Unlike other techniques ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

rafanadal2011
not rated yet Mar 03, 2011
Findrxonline says on its website that should further investigate that only thus will achieve the goal of finding a cure for Alzheimer's disease.