Correcting damaged neurons in frontotemporal dementia

by Madlen Davies for The dDaily Mail:

Scientists are a step closer to developing a pill to cure dementia.

A team in Belgium were able to repair diseased brain cells taken from patients with a common form of the condition, for which there is no cure.

They identified a gene variant that prevents neurons from forming properly, and managed to correct it through genetic engineering.

The researchers found they could also correct alter the gene a compound that inhibited a chemical responsible for the gene mutation.

They have hailed the discovery a breakthrough, believing it could pave the way for a new 'dementia pill'.

The study used stem cells from three patients with a type of dementia called 'frontotemporal dementia', which accounts for about half of cases diagnosed in patients before the age of 60.

There is currently no cure for this type of the condition, which runs in families.

Frontotemporal disorders are the result of damage to neurons in parts of the brain called the frontal and temporal lobes, gradually leading to behavioural symptoms or language and emotional problems.

Mutations in a gene called GRN (progranulin) are believed to be behind frontotemporal dementia, but versions of the condition in mice do not mimic all the features of the human type.

So the Belgian researchers recreated dementia in a laboratory dish using human iPSCs (induced pluripotent stem cells) to help identify a potential new treatment strategy.

Molecular biologist Professor Catherine Verfaillie, of the Catholic University of Leuven, said: 'Use of induced pluripotent stem cell technology makes it possible to model dementias that affect people later in life.'

The technique involves taking skin cells from patients and reprogramming them into embryonic like stem cells capable of turning into other specific cell types relevant for studying a particular disease.

Professor Verfaillie added the research could pave the way for a pill to treat frontotemporal dementia to be developed.

She said: 'iPSC models can now be used to better understand dementia, and in particular frontotemporal dementia, and might lead to the development of drugs that can curtail or slow down the degeneration of cortical neurons.'

The patients in the study all carried a GRN mutation which prevented their immature iPSCs from turning into mature, specialised cells called cortical neurons, the cell type most affected in frontotemporal dementia.

One of the top defective pathways in the iPSCs was a signalling pathway known as Wnt, which plays an important role in the development of neurons.

But genetic correction or treatment with a compound restored the ability of the iPSCs to turn into cortical neurons.

Taken together, the findings demonstrate the GRN mutation causes the defect in cortical neuron formation by altering the Wnt signalling pathway.

Researcher Dr Philip Van Damme, of the Leuven Research Institute for Neuroscience and Disease, added: 'Our findings suggest signalling events required for neurodevelopment may also play major roles in neurodegeneration.

'Targeting such pathways, as for instance the Wnt pathway presented in this study, may result in the creation of novel therapeutic approaches for frontotemporal dementia.'

The researchers will now work to better understand what goes wrong in GRN mutated cells, as well as identify precise molecular targets that could then be used for drug screens.

The study was published in the journal Stem Cell Reports.

It comes after a major research project published this month found simple lifestyle changes could see 80,000 people saved from dementia every year.

The study suggests that people make changes earlier in life to cut the risk of developing the brain disease as they grow old.

Source: http://dailym.ai/1tn9jqiPhoto: Frontotemporal dementia is the result of damage to neurons in parts of the brain called the frontal (pictured in blue) and temporal (pictured in purple) lobes. There is no currently no cure and it runs in families