Major new research finding raises some old questions

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Hot on the heels of ‘Brain Awareness Week’, comes ‘National Science Week’, with the University of Sheffield enthusiastically organising a numerous activities in their week-long Festival of Science and Engineering, including today’s Open Day at the Sheffield Institute of Translational Neuroscience (SITraN). This event was to include talks by Dr Chris McDermott and Prof Pam Shaw on MND and the role that SITraN plays in the search for effective treatments for neurodegenerative disease.

Unfortunately…… last night’s snow has put the kibosh on that, so instead of heading up the M1 to Sheffield, I decided to use some of the saved time to catch up on some reading – in particular a recent paper that came out in the journal Nature, from an international consortium, led by the scientists from the Austrian Academy of Sciences in Vienna.

The best seven pages in ten years

A senior MND researcher emailed me to say it’s one of the best papers he’s read in the past 10 years and I can understand where he’s coming from. Not only does the research identify a previously unknown cellular process that causes selective motor neuron degeneration, but it also appears to tie together several of the pieces of the pathological jigsaw: disruption of RNA metabolism, oxidative stress and programmed cell death pathways.

As impressive is the sheer amount of work that has gone into this seven-page paper. OK, there are also several extra pages of online supplementary material (one of the great benefits of online publication) but I reckon there is the equivalent of at least three PhD theses and several years of work in there!  

In a nutshell, the researchers created a mouse that has a defect in an enzyme called CLP1 and these mice develop progressive motor neuron degeneration. I’m not going to go into the detail, but rather focus on one interesting item that was buried in the text.

Genetic environment matters for CLP1

When researchers initially tried to create the mice they found that the mice all died well before birth. So they tried using a different strain of mice, but got the same result.

A third strain produced live mice, with normal numbers of motor neurons at birth. However from about the age of four months, these mice then developed a progressive muscle weakness and loss of motor neurons over the course of several months.

The paper focuses in on what’s going on in these mice, but it also raised additional questions for me, such as:

“Why did these mice survive into adulthood, when two other mouse strains didn’t – and is there something different in the genetic make-up of these mice that has basically protected them into adulthood rather than killing them as embryos?”

MND Association funded research on genetic environment

Other groups have noticed that when SOD1 mice are bred on different background strains, it can have a profound effect on disease progression and survival. This brings us nicely back to SITraN, as Prof Shaw and her colleagues are looking at precisely this issue, in an MND Association-funded collaboration with Prof Caterina Bendotti in Milan.

They are looking at the gene expression profiles (basically which genes are switched on and off) in the motor neurons of two strains of SOD1 mice, one of which develops the disease and later age and also lives much longer.  By working out patterns that are linked to specific biological processes, they are starting to pinpoint pathways which are driving the disease and also which ones might be slowing the disease. Some of their findings were presented at the most recent International Symposium (Abstract C61).

If there are protective genes at work in the mice, might the same be happening in humans?

The search for ‘good’ genes hots up

I’m often asked about Steven Hawking – how come he’s lived so long?  For years, one of my pet theories has been that there is something in his genetic make-up that didn’t stop the disease from occurring, but is ‘pushing back’. That’s becoming an increasingly popular and productive area of investigation – as genetic researchers extend their focus from finding ‘bad’ genes that cause or predispose people to develop MND, to potentially ‘good’ genes that might slow down the disease. A couple of candidates have been identified, most notably the EphA4 gene.

The search for these disease-modifying genes needs joined up collaboration between researchers around to world and it’s heartening to see how everyone in the field is starting to get together to pool their samples and data, which will allow the genetic profiles of those with exceptionally slowly progressing MND to be analysed in much larger numbers than ever before. If good genes can be identified and their roles understood, it will open up exciting new treatment opportunities.