Investigating C9orf72 and TDP-43 proteins in a fruitfly model of MND

Background to C9orf72 toxicity

We know that damage to C9orf72 (both the gene and the protein it makes) is a crucial step in why some people get MND and why some people get frontotemporal dementia. There are three possible reasons why C9orf72 is toxic. 1) the way the gene is damaged alters how it normally works. 2) the formation of clumps of RNA – a by-product of the damage and not normally seen in cells, and 3) the formation of very short, new and unwanted proteins called ‘dipeptide repeats’ or ‘DPRs’, again these are not normally seen..

There’s evidence of all three types of toxicity within the motor neurone, but we don’t know how they work together or if one is more toxic than another. We also know that the protein TDP-43 forms clumps in motor neurones affected by the C9orf72 gene.Read More »

Pretty ‘fly’ for a fruit fly

A fruit fly

Dr Frank Hirth is one of the world’s leading fruit fly MND researchers. Based at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, he has been working on an Association-funded project developing a C9orf72 fruit fly model of MND. Here we mark the end of this project, and report on what the researchers have achieved.

Background

In September 2011, an international collaboration, co-funded by the Association, had discovered a genetic mistake within the C9orf72 gene that was found to cause almost 40% of cases of inherited MND. Read More »

MND Awareness Month: Blog a day… coming soon!

June is MND Awareness Month and this year our campaign is featured around the theme ‘VOICE’. Awareness month is our opportunity to raise awareness of MND, making society better informed about the disease. Here in the Research Development team, we are using our global research voice to raise awareness on our MND Research blog.

Dr Frank Hirth (Institute of Psychiatry, King's College London) signs the MND Charter
Dr Frank Hirth (Institute of Psychiatry, King’s College London) signs the MND Charter

Our political voice:

80-95% of people living with MND will face communication problems* as their speech deteriorates. Through local and national campaigning we can give people living with MND a voice; be it signing the MND Charter or by influencing the National Institute for Health and Care Excellence (NICE) guidelines on MND.

Motor neurones lose their voice:

However, it’s not just about our voice. Dr Frank Hirth (Institute of Psychiatry, King’s College London) stated during our Spring Conference in Manchester earlier this month: “Motor neurones affected by the protein TDP-43 ‘lose their voice’ and ability to communicate in MND” You can watch Dr Hirth’s presentation online here.

Our global research voice:

We will be posting a blog a day (maybe even two!) to raise awareness of all aspects of MND research. These guest blogs will be written by a variety of different people (researchers, lab managers and even finance teams!) with the aim of raising awareness of MND this June.

As a ‘sneak preview’ here’s a taste of what’s to come from 1 June 2014:

  • fundraising events by our researchers (including meerkats!)
  • research project updates (such as BioMOx and our zebrafish research)
  • job roles of specific people (including Rachel from the International Alliance).

So, to find out more about MND research make sure you visit this blog every day in June for our ‘blog a day’! You can even subscribe (via our subscribe box on the right-hand sidebar) to receive new blog posts straight in your email inbox!

blog a day1

*Beukelman et al 2011

Flying towards understanding: MND, TDP43, flies and a competition

Dr Frank Hirth King's College London
Dr Frank Hirth, King’s College London

The MND Association has funded a number of research projects in the laboratory of Dr Frank Hirth at the Institute of Psychiatry, King’s College London. His area of expertise is in using fruit flies to understand how motor neurones die in MND.

There is an opportunity to read a summary of some of his work through an online competition. The article is called ‘The TBPH gene – do neurodegenerative disease have a fly in the ointment’ and it is has been shortlisted forThe People’s Choice award , as part of the Access to Understanding competition.

Please go online, read the article, ‘like it’ and add any comments you’d like to, until a deadline of 12 noon on 24 March.

A background (but hopefully not a spoiler!) to this summary and the competition is given below:

Read More »

The C9orf72 mystery begins to unravel even more of its secrets

In 2011 an international team of scientists, including three MND Association-funded researchers, identified the elusive C9orf72 gene located on Chromosome 9. Since this ground-breaking discovery, researchers from around the world have been trying to find a way to open-up and reveal more about this MND-causing gene.

Determined to get inside and unravel the secrets behind C9orf72, the Association is funding a number of new and exciting research projects to help solve the mystery. These projects look at, not one, but a number of different aspects to try and understand more about C9orf72.

In order to solve this mystery our C9orf72 researchers are following the clues using zebrafish, mice, flies and DNA samples.

How the C9orf72 MND mystery began

We each contain copies of 23 pairs of chromosomes, including the X and Y sex chromosomes. These chromosomes contain thousands of genes that portray our characteristics such as hair and eye colour. These genes are made up of DNA which can either be ‘coding’ to make a protein, or ‘non-coding’. For details of how genes make a protein see our earlier blog post.

Before C9orf72 was identified researchers had focused on an area on Chromosome 9 that appeared to be connected with both the rare inherited form of MND and the related neurodegenerative disease frontotemporal dementia (FTD).

Using a number of cutting-edge techniques the international team isolated the C9orf72 gene expanded GGGGCC hexanucleotide repeat as being a crucial player in both inherited MND and FTD. Not only did the researchers find a link between MND and FTD, they also found that C9orf72 was found in approximately 40% of cases of inherited MND (where there is a strong family history). This means that we now know 70% of the genes that cause the rare inherited form of MND. For more details on C9orf72 see our earlier blog post.

For more information on inherited MND please see our website.

So, researchers found C9orf72. The next question was ‘What does it do? Is the gene defect repeat itself, or the protein it makes responsible for causing MND? And what goes wrong in MND?’

Detective
Following the clues to solve C9orf72

Two recent research clues

Since 2011 researchers have been trying to answer these questions and find out more about C9orf72. This has led to a dramatic increase in research, including two papers published in February and March this year!

Prof Christian Haass (Munich Centre for Neurosciences, Germany), who recently presented at our 23rd International Symposium on ALS/MND in December 2012, published a paper on the 7 February in the journal Science. The second paper lead by Prof Leonard Petrucelli (Mayo Clinic, USA) was published open access in the journal Neuron on the 20 February.

In a big surprise, both researchers found that the presumed ‘non-coding’ C9orf72 GGGGCC repeat expansion actually made a protein. Normally these ‘non-coding’ regions do not make proteins so this was a very big surprise indeed!

The researchers found that these proteins formed large clumps in the brains, and throughout the central nervous system (CNS), of people with C9orf72 MND and/or FTD. Importantly, they did not find these clumps in healthy individuals or those with other neurological disorders.

It is currently unknown as to whether these protein clumps are involved in MND and/or FTD, but they may be a potential biomarker or a therapeutic target in this most common type of MND. The next step is for the researchers to find out whether these proteins actually cause MND and/or FTD.

Finding more evidence to piece together the clues

In addition to these two papers looking into the mystery behind C9orf72, the Association is funding some exciting new research projects, each looking at different things, to further understand more about this gene.

Dr Johnathan Cooper-Knock
Dr Johnathan Cooper-Knock, MRC/MND Association Lady Edith Wolfson Clinical Research Fellow

Dr Johnathan Cooper-Knock (Sheffield Institute for Translational Neuroscience, UK) is already trying to identify how C9orf72 causes MND by utilising a genetic technique known as gene expression profiling. He is using samples from the Association’s DNA bank which are positive for the C9orf72 genetic mistake. Gene expression profiling is a technique which allows researchers to understand how the activity of genes contributes towards causing MND. (Traditional genetic studies are designed to look at which genes are affected, rather than their activity – ie when and how). Read more about Johnathan’s project here.

Developing new disease models enables us to understand the causes of MND and to test new therapies. One way to understand the function of C9orf72 and how this goes wrong in MND is to create a model. Our current research projects are developing new C9orf72 models in flies, mice and zebrafish.

Dr Frank Hirth (Kings College London, UK) will be producing a fly model, Dr Javier Alegre Abarrategui (University of Oxford) will be making a mouse model and Dr Andrew Grierson (University of Sheffield, UK) will be creating a zebrafish model.

All of these models aim to understand the function of C9orf72 and what goes wrong. The researchers hope to study what happens in MND and how this occurs by looking at behaviour and what happens when C9orf72 is ‘switched’ on and off. For more information about these exciting research projects please see our website.

Solving the mystery

All of our C9orf72 Association-funded research projects are using different approaches to look at C9orf72 in different ways as we are still unsure whether the protein or the repeat is the problem. From mice to flies all of these research projects together are helping to solve the mystery of C9orf72 and MND.

With the proteins formed by C9orf72 likely to be a potential biomarker or therapeutic target the two recent papers are adding to the growing number of clues, pointing researchers in the right direction to unravelling and solving the secrets of C9orf72.

References:

Mori, K. et al. The C9orf72 GGGGCC Repeat Is Translated into Aggregating Dipeptide-Repeat Proteins in FTLD/ALS. Science. 339(6125): 1335-1338. 2013 DOI: 10.1126/science.1232927

Ash, P. E. A. et al. Unconventional Translation of C9ORF72 GGGGCC Expansion Generates Insoluble Polypeptides Specific to c9FTD/ALS. Neuron. 77(4): 639-646. 2013 DOI: 10.1016/j.neuron.2013.02.004

Come fly with me

The Fly
The Fly. Courtesy of MND Association funded researcher Dr Frank Hirth, based at King’s College London

Although millions of years of evolution separate humans from insects, a tiny fruit fly called Drosophila melanogaster has been one of the most extensively studied organisms for more than a century, leading to many advances in research. But why are flies so useful? And can we really learn anything from them?

Why fly?

It is easy to see that this fly has advantages in the laboratory. They are very small and easy to keep, but still large enough to study in detail with relatively simple microscopes. They breed easily from 10 days old, producing many genetically identical offspring from each mating. This makes it easy to study several generations over a matter of weeks.

Simple yet sophisticated

Although considered a simple species, the fly is actually quite sophisticated, with structures that are equivalent to organs such as the heart, kidneys and gut.  The brain and nervous system are considered particularly complex, making the fly valuable for the study of neurodegenerative diseases.

Genetically the fruit fly is also much simpler than a human – it has approximately half the number of genes that we do. But it’s not the number of genes you have that counts; it’s what you do with them!

Luckily, about three-quarters of the genes implicated in human disease have a related gene in the fly, with a high level of similarity between the two. Many methods and techniques have been developed, so researchers can switch the fly’s genes on and off at various points in its life-cycle, or in different parts of the body, and then observe the consequences.

MND fly research

Between 2004 and 2009, only about four scientific papers per year described studies using these fruit flies for MND research. In conjunction with the recent upsurge in genetic discoveries related to MND, there has been a rapid increase to twelve publications in 2010, and a further seven already in 2011.

The MND Association is a leader in funding and promoting cutting edge research and we are currently funding two PhD studentships making extensive use of the fruit fly. You can find out more about these projects on our website:

Understanding disease mechanisms of MND in the fruit fly

How does faulty TDP-43 affect MND in fruit flies?

Learning to fly toward drug discovery

There is considerable interest in using the fly to test potential drugs for MND, as there has been some success in this approach in other conditions.  Like the zebrafish model many more substances can be tested than would be possible with a mouse model, and the results may tell scientists more than a cell-based screen. However, this is not yet a routine approach to drug discovery – historically fruit flies have not been used in this way by pharmaceutical companies. It remains to be seen whether any promising compounds identified using fly models will actually progress to being drugs for the treatment of human diseases.

For such an approach to be useful for MND, there needs to be a reliable and relevant fly model. Recently published work has been focussed on exploring the role of proteins known to be involved in MND such as TDP-43 and FUS. When they publish their work, researchers often hint that their models will be useful in the development of new treatments, even if this was not their main aim.

The use of the fly to discover new medicines may still be some way off, but we can be sure that the tiny fruit fly is already contributing to research in a very big way.