• Scientists have identified a ‘Pac-man’ gene that protects the brain from a toxic protein. (BSIP/UIG Via Getty Images)
Aussie scientists have discovered how a ‘Pac-man’ gene helps break down toxic proteins that can cause Alzheimer’s disease.
By
Kemal Atlay

26 Jul 2016 - 2:27 PM  UPDATED 26 Jul 2016 - 3:47 PM

Aussie scientists have discovered how a ‘Pac-man’ gene helps breakdown toxic proteins that can cause Alzheimer’s disease.

Australian scientists have identified a ‘Pac-man’ gene that protects the brain from a toxic protein implicated in the development of Alzheimer’s disease, according to a new study.

Researchers from Neuroscience Research Australia analysed both animal models and human brain tissue samples and discovered that the ABCA7 gene plays a crucial role in protecting the brain from the harmful build-up of the amyloid-beta protein. The study was published today in the Journal of Alzheimer’s Disease.

“ABCA7 has been around for a number of years, but just in recent years it has been identified as one of the key genes that’s associated with Alzheimer’s disease – so until now, the function of ABCA7 was unknown in the brain,” lead author Dr Woojin Kim, a neuroscience and Alzheimer’s disease expert from UNSW, tells SBS.

“Alzheimer’s disease is one of the most important health issues in the 21st century and currently there’s no cure or effective treatment for it, so obviously there’s an urgency for new developments.”

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Alzheimer’s disease is a neurodegenerative disorder that affects up to 70 per cent of all people with dementia. Dementia is the single greatest cause of disability in Australians aged 65 years and older and is estimated to affect over 350,000 people in Australia.

“We’ve been able to show that [ABCA7] is involved in the clearance of the amyloid-beta protein in the brain.”

Too much of the amyloid-beta protein can be toxic to the nerve cells in the brain and is seen as a key player in the development of Alzheimer’s disease.

Plaques can form if the amyloid-beta is left unchecked by the brain’s microglia, or scavenger cells. The microglia relies on the protein produced by the ABCA7 gene to function properly and ‘chomp up’ the amyloid-beta masses.

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“The microglia just goes around the brain and looks for anything that shouldn’t be there, so it detects the toxic amyloid-beta protein and then attempts to clear it or chomp it up,” says Dr Kim.

“It works similar to a Pac-man, but without ABCA7 protein in the microglia, the microglia loses its efficiency.”

Dr Kim’s work shows that an impaired function of ABCA7 contributes the pathology associated with Alzheimer’s disease, which has major implications for future treatment therapies.

Prof Steve Robinson, a neuroscientist from RMIT, says the research is unique in that it seeks to manipulate the brain’s natural defences in fighting neurodegenerative disorder, rather than introducing foreign drugs.

“Previous studies have focused on either getting drugs into the brain that will break down amyloid directly or getting antibodies into the brain that will provoke an immune response to amyloid – both of those are a fairly artificial approach,” Prof Robinson tells SBS.

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“This particular study is defining the way the brain does it normally and then saying perhaps we can harness that and use that in therapeutic processes.”

He says that amyloid-beta build-up “is a huge pathological feature” of Alzheimer’s disease and that the research provides a new avenue for investigating the role of amyloid-beta proteins.

According to Dr Kim, the next step in the research will be to investigate the mechanisms behind ABCA7 expression and whether this can be controlled.

“We need to understand how the ABCA7 gene is turned on and turned off and why this functions in some people but not in others,” he says.

“Once we know that, we’ll be able to control its expression in the brain and thereby initiate this clearance of amyloid-beta proteins.”