Huntington’s disease affects roughly 4,700 Canadians. Compared to Alzheimer’s, a more common neurodegenerative disease, which affects hundreds of thousands of Canadians, Huntington’s is not as frequently studied, yet just as much a mystery to doctors and researchers.
Working with a yeast model of Huntington’s, Patrick Lajoie is uncovering some of that mystery.
His research received $196,512 from the Canada Foundation for Innovation’s John R. Evans Leaders Fund – part of a larger $52-million investment in 220 new infrastructure projects at 51 universities – which allows researchers from around the country to carry out ground-breaking research in world-class facilities.
His project is one of four at Western receiving funding.
“I’m a yeast geneticist. We use yeast as a model organism to identify the basic cellular processes that are involved in different human diseases,” said the Anatomy and Cell Biology professor.
Huntington’s is an inherited disease that results in death of brain cells. If one parent is affected, a child’s chances of developing the disorder are 50-50. The earliest symptoms are often subtle problems with mood or mental abilities, followed by impaired coordination, an unsteady gait or jerky body movements. Physical conditions decline until coordinated movement is difficult and the patient isn’t able to walk. Cognitive abilities worsen and decline into dementia. As is the case with other neurodegenerative diseases, the onset of symptoms is usually later in life – when the patient is between 30-50 years of age.
“The protein and gene responsible for (Huntington’s) has been identified, so you can get tested early and know if you will get the disease. We take that human protein and express it in yeast, and it induces a growth defect. The yeast doesn’t like (the protein), but it doesn’t kill it right away,” Lajoie explained.
The Huntington protein is expressed from birth; the affected individual will have it, but it’s not toxic to young cells. Symptoms of the disease appear in older adults, so the protein must become increasingly toxic as the person ages. Lajoie is looking at young cells and studying what mechanisms they have to prevent toxicity, and why neurons start dying when they get older. The two aims of his project are to look at the toxicity of the Huntington protein overall, but also to find out more about its age-dependent toxicity.
“The way we assess that is by using yeast as a model organism. As we see in mammalian cells, the Huntington protein (in yeast) doesn’t kill young yeast, but kills old yeast. We have aging yeast we grow in a test tube and leave for a month and it gives us a nice model to study age-dependent toxicity,” he said.
“We want to look at what genes are expressed in young cells, and which are not expressed in old cells, and vice versa, and unmask the toxicity with age.”
Using a yeast model is more feasible than using an animal model for this kind of study, Lajoie added. Yeast lives for two weeks, or up to a month, based on which strain you are using. Mice live for two years. If you want to have any kind of meaningful data for aging in a mouse, it will require 30 mice; it will take more time and be more expensive. Yeast is cheap, allows for a model with a completely sequenced genome and yields more rapid results.
“We also have a mammalian tissue culture model with Huntington’s, and we have human patients with the Pathology Department, so we can go back and forth between the different models and really test whether what we find in yeast is applicable or relevant to a higher organism,” he continued.
“The challenge is to try and identify these aging components. There’s been a lot of work done on trying to figure out Huntington’s and a lot of different models. There’s a dozen animal models for Huntington’s, but they all have different features, so which one you’re picking and how reproducible it is from model to model – that’s why it’s important to go back and forth between models and human samples.”
Another challenge for Lajoie is Huntington’s is rare. Patient cohort samples in studies are small. It’s “not a sexy disease like Alzheimer’s or cancer,” he said, and it doesn’t attract the same amount of research dollars.
Research development from biotech companies is likewise slim because there’s not much money to be made. Even without a cure, there’s aren’t enough patients for companies to make money, whereas with Alzheimer’s there would be, Lajoie noted. He’s hoping his research can contribute to this void.
From delving into the modeling neurodegenerative diseases to looking into digital philosophy, four Western researchers will share in nearly $1 million in funding through the Evans Leaders Fund.
Officially announced last week, MPs Kate Young (London West), Parliamentary Secretary of Science, and Peter Fragiskatos (London North Centre) were at Western today to celebrate the funding.
In addition to Lajoie, Western researchers receiving funding include:
- Mathias Dietz, School of Communication Sciences and Disorders, $200,000, Equipment for bilateral hearing assessment of cochlear implant subjects;
- Alan Getgood, Surgery, $320,000, Mechanobiological Solutions to Joint Injury and Degeneration; and
- David Bourget, Philosophy, $200,000, PhilNet: A Research Tool for Digital Philosophy.