Defective garbage disposal cells in brain may explain Alzheimer’s toll

Molecular debris in the brain can cause inflammation. Above, a tangle of proteins common in the brains of Alzheimer’s Disease patients. Photo via Wikimedia Commons

It’s been quite a week for Alzheimer’s Disease. Earlier this week, we posted about research into how tau proteins build up in neurons. Now a group of Stanford researchers have demonstrated that a flawed garbage collection system may be responsible for much of Alzheimer’s damage to brain cells.

The brain has immune cells called microglia that are bodyguards and garbage collectors: they attack foreign invaders and also clear up molecular trash that can cause inflammation in the brain. The team, led by CIRM grantee Tony Wyss-Coray, compared the brains of five people who died of Alzheimer’s and five who died of other causes. They found that a protein called beclin, which is critical to many cell types, was severely depleted in the brains of people with Alzheimer’s.

The scientists found that beclin was a critical piece of the microglias’ mechanism for recycling cell surface receptors that are key to the cells’ ability to hoover up and digest trash. In essence, the brain’s garbage truck fleet was short on spark plugs.

A press release from Stanford quoted Wyss-Coray,

“Most research has focused on neurons….Our findings suggest that we should also be looking at other cell types that may be malfunctioning in the brain. If microglia don’t work the way they’re designed to work, a lot of problems may result.”

The study was published last week in the scientific journal, Neuron. Further research into the role beclin plays in Alzheimer’s is necessary since Wyss-Coray’s team was only able to look at so few patients’ brains, but the results have implications for other neurodegenerative diseases as well – a mutation in the same receptor-recycling system.

CIRM funds researchers who are tackling Alzheimer’s from several angles, including early development for possible treatments. You can learn more on our Alzheimer’s Fact Sheet.

Rina Shaikh-Lekso

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