Prions link cholesterol to neurodegeneration

Feb 12, 2008

Prion infection of neurons increases the free cholesterol content in cell membranes. A new study published in the online open access journal BMC Biology suggests that disturbances in membrane cholesterol may be the mechanism by which prions cause neurodegeneration and could point to a role for cholesterol in other neurodegenerative diseases.

It is widely believed that prions (protein only infectious material) are the cause of rare progressive neurodegenerative disorders that affect both humans and animals. A prion is an infectious agent made solely of protein. However what is not known is how the prions damage brain cells (neurons).

Dr Clive Bate and colleagues from the Royal Veterinary College in the UK compared the amounts of protein and cholesterol in prion-infected neuronal cell lines and primary cortical neurons with uninfected controls. Protein levels were similar but the amount of total cholesterol (a mixture of free and esterified cholesterol) was significantly higher in the infected cell lines. The cholesterol balance was also affected: the amount of free cholesterol increased but that of cholesterol esters reduced, suggesting that prion infection affects cholesterol regulation.

The team attempted to reproduce the effects of prions on cholesterol levels, by stimulating cholesterol biosynthesis or by adding exogenous cholesterol. Both approaches resulted in increased amounts of cholesterol esters but not of free cholesterol. The free cholesterol is thought to affect the function of the cell membranes and to lead to abnormal activation of phospholipase A2, an enzyme implicated in the depletion of neurons in prion and Alzheimer’s disease.

Studies have recently shown that the controlling cholesterol levels within the brain is critical in limiting the development of neurodegenerative diseases such as Alzheimer’s, Parkinson’s and prion diseases, multiple sclerosis, and senile dementia. This study now gives far more specific insight into the kind of mechanisms at work. Dr Bate stated: “Our observations raise the possibility that disturbances in membrane cholesterol induced by prions are major triggering events in the neuropathogenesis of prion diseases”.

Source: BioMed Central

Explore further: Is fleet diversity key to sustainable fisheries?

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Is fleet diversity key to sustainable fisheries?

24 minutes ago

Concern about fisheries is widespread around the world. Over the past several decades, a robust discussion has taken place concerning how to manage fisheries better to benefit ecosystems and humans. Much of the discussion ...

Strange, fanged deer persists in Afghanistan

1 hour ago

More than 60 years after its last confirmed sighting, a strange deer with vampire-like fangs still persists in the rugged forested slopes of northeast Afghanistan according to a research team led by the Wildlife ...

Captive rhinos exposed to urban rumbles

2 hours ago

The soundtrack to a wild rhinoceros's life is wind passing through the savannah grass, birds chirping, and distant animals moving across the plains. But a rhinoceros in a zoo listens to children screaming, cars passing, and ...

'Divide and rule'—raven politics

3 hours ago

Mythology has attributed many supernatural features to ravens. Studies on the cognitive abilities of ravens have indeed revealed that they are exceptionally intelligent. Ravens live in complex social groups ...

User comments : 0

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.