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Running triggers production of a molecule that repairs the brain in animal models of neurodegenerative disease
octobre 11, 2016
Researchers at The Ottawa Hospital and the University of Ottawa have discovered that a molecule triggered by running can help repair certain kinds of brain damage in animal models. They found that this molecule, called VGF nerve growth factor inducible, helps to heal the protective coating that surrounds and insulates nerve fibres. Their study, published in Cell Reports, could pave the way for new treatments for multiple sclerosis and other neurodegenerative disorders that involve damaged nerve insulation.
“We are excited by this discovery and now plan to uncover the molecular pathway that is responsible for the observed benefits of VGF,” said Dr. Picketts, senior author of the paper and a senior scientist at The Ottawa Hospital and professor at the University of Ottawa. “What is clear is that VGF is important to kick-start healing in damaged areas of the brain.”
The team made this discovery while studying mice genetically modified to have a small cerebellum, the part of the brain that controls balance and movement. These mice had trouble walking and lived only 25 to 40 days.
However, if these mice were given the opportunity to run freely on a wheel, they lived over 12 months, a more typical mouse lifespan. The running mice also gained more weight and acquired a better sense of balance compared to their sedentary siblings. However, they needed to keep exercising to maintain these benefits. If the running wheel was removed, their symptoms came back and they did not live as long.
Looking at their brains, the researchers found that the running mice gained significantly more insulation in their cerebellum compared to their sedentary siblings.
To find out why running was causing this insulation, the team looked for differences in gene expression between the running and sedentary mice and identified VGF as a prime candidate. VGF is one of the hundreds of molecules that muscles and the brain release into the body during exercise. It also has an anti-depressant effect that helps make exercise feel good.
When the research team used a non-replicating virus to introduce the VGF protein into the bloodstream of a sedentary mutant mouse, the effects were similar to having the mouse run – more insulation in the damaged area of the cerebellum, and fewer disease symptoms.
“We saw that the existing neurons became better insulated and more stable,” said Dr. Matías Alvarez-Saavedra, the lead author on the paper. “This means that the unhealthy neurons worked better and the previously damaged circuits in the brain became stronger and more functional.”
Dr. Alvarez-Saavedra obtained his PhD in Dr. Picketts’ research group, and is currently a postdoctoral fellow at the New York University School of Medicine and the Howard Hughes Medical Institute.
“We need to do broader research to see whether this molecule can also be helpful in treating multiple sclerosis and other neurodegenerative diseases,” said Dr. Picketts.
This study was funded by the Canadian Institutes of Health Research, with support from The Ottawa Hospital Foundation. The group has now received funding from the MS Society of Canada and the Canadian Partnership for Stroke Recovery to further investigate VGF. Dr. Picketts is also a member of the University of Ottawa Brain and Mind Research Institute. Dr. Alvarez-Saavedra is funded by a Pew Latin American Postdoctoral Fellowship in the Biomedical Sciences.
Full reference: Voluntary running triggers VGF-mediated oligodendrogenesis to prolong the lifespan of Snf2h-null ataxic mice. Matías Alvarez-Saavedra, Yves De Repentigny, Doo Yang, Ryan W. O’Meara, Keqin Yan, Lukas E. Hashem, Lemuel Racacho, lya Ioshikhes, Dennis E. Bulman, Robin J. Parks, Rashmi Kothary, and David J. Picketts. Cell Reports (2016), http://dx.doi.org/10.1016/j.celrep.2016.09.030. October 11, 2016.
About The Ottawa Hospital: Inspired by research. Driven by compassion. The Ottawa Hospital is one of Canada’s largest learning and research hospitals with over 1,100 beds, approximately 12,000 staff and an annual budget of over $1.2 billion. Our focus on research and learning helps us develop new and innovative ways to treat patients and improve care. As a multi-campus hospital, affiliated with the University of Ottawa, we deliver specialized care to the eastern Ontario region, but our techniques and research discoveries are adopted around the world. We engage the community at all levels to support our vision for better patient care. See www.ohri.ca for more information about research at The Ottawa Hospital.
About the University of Ottawa: The University of Ottawa is home to over 50,000 students, faculty and staff, who live, work and study in both French and English. Our campus is a crossroads of cultures and ideas, where bold minds come together to inspire game-changing ideas. We are one of Canada’s top 10 research universities—our professors and researchers explore new approaches to today’s challenges. One of a handful of Canadian universities ranked among the top 200 in the world, we attract exceptional thinkers and welcome diverse perspectives from across the globe. www.uottawa.ca
Media Contact: Amelia Buchanan, Senior Communication Specialist, Ottawa Hospital Research Institute; ambuchanan@ohri.ca; Office: 613-798-5555 x 73687; Cell: 613-297-8315
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