Tag Archives: Huntington’s Disease

Protein levels linked to dementia

Scientists have made a breakthrough in the battle to beat early-onset dementia.

Using animal models, researchers have discovered how a protein deficiency may be linked to frontotemporal dementia – a form of early-onset dementia that is similar to Alzheimer’s disease.

They say the results lay the foundation for therapies that one day may benefit those who suffer from the illness and related diseases that wreak havoc on the brain.

As its name implies, FTD is a fatal disease that destroys cells, or neurons, that comprise the frontal and temporal lobes of the brain – as opposed to Alzheimer’s which mainly affects brain’s memory centres in the hippocampus.

Early symptoms of FTD include personality changes, such as increased erratic or compulsive behaviour. Sufferers later experience difficulties speaking and reading, and often suffer from long-term memory loss.

Alzheimer’s

Alzheimer’s

FTD is usually diagnosed between the ages of 40 and 65, with death occurring within two to 10 years after diagnosis. No drug exists to slow, halt or reverse the progression of FTD.

The new study, led by Doctor Robert Farese, offers new hope in the fight against this and other related conditions.

Dr Farese and his team showed how a protein called progranulin prevents a class of cells called microglia from becoming ‘hyperactive.’


Without adequate progranulin to keep microglia in check, this hyperactivity becomes toxic, causing abnormally prolonged inflammation that destroys neurons over time-and leads to debilitating symptoms.

Dr Farese, who is a professor at the University of California, San Francisco, said: ‘We have known that a lack of progranulin is linked to neurodegenerative conditions such as FTD, but the exact mechanism behind that link remained unclear.

‘Understanding the inflammatory process in the brain is critical if we are to develop better treatments not only for FTD, but for other forms of brain injury such as Parkinson’s disease, Huntington’s disease and multiple sclerosis.’

Gene therapy for Huntington’s disease

A new gene-silencing strategy can reverse core symptoms associated with Huntington’s disease, according to a preclinical study.

The short-term therapy produced sustained benefits in both mouse and primate animal models of this neurodegenerative disorder, which currently lacks an effective treatment.

“Our approach is feasible for development now into a therapy for Huntington’s disease in man,” said senior study author Don Cleveland of the University of California at San Diego.

Huntington’s disease is a fatal condition marked by uncontrolled movements and cognitive and psychiatric problems. It arises from mutations in the huntingtin gene, which cause toxic protein fragments to build up in the brain.

Previous preclinical efforts aimed at blocking the production of mutant huntingtin protein have fallen short because they have been directed at a small portion of the brain.

“Because huntingtin is widely expressed, targeting multiple brain regions will likely be required for an effective treatment,” Cleveland stated.

Huntington's disease

Huntington’s disease

In the new study, Cleveland and his team reduced mutant huntingtin levels across brain regions in several mouse models of Huntington’s disease and in nonhuman primates. They achieved a long-lasting drop in huntingtin levels through the transient, one-time infusion of single strands of DNA—called antisense oligonucleotides (ASOs)—which selectively bind to and degrade molecules that contain instructions for making the mutant protein.

The motor performance of treated animals started improving within 1 month and reached normal levels within 2 months. Psychiatric and motor benefits lasted 9 months after treatment, long after mutant huntingtin levels began to rise again.


“This finding has implications more broadly for therapy in any of the age-dependent neurodegenerative diseases that develop from prolonged exposure to a mutant protein,” Cleveland said.

Moreover, the therapy blocked brain atrophy and increased lifespan in mutant mice with a severe form of the disorder. Because ASOs have proven to be safe in clinical trials, with one approved drug and dozens under development, this approach is promising not only for Huntington’s disease, but also for other neurodegenerative disorders with a known genetic cause.