Helping the brain heal itself

Slack Ruth

“If we can unlock the mechanisms that control neurogenesis, we can probably speed up recovery for stroke victims and improve treatment for diseases like Alzheimer’s and Parkinson’s.”

– Ruth Slack

Your brain is growing and Ruth Slack wants to know how.

For more than a century, scientists believed that no new neurons ever formed in the adult mammalian brain. We were born, it was argued, with all the neurons we would ever get. Then, about 15 years ago, scientists discovered something revolutionary— that your brain can generate new neurons throughout your entire adult life in a process called “neurogenesis.”

In patients suffering from stroke, Alzheimer’s and Parkinson’s disease, brain cells are destroyed or damaged. Imagine if you could figure out exactly what it is that signals the brain to create new brain cells—that is, trigger neurogenesis—and then find a way to expand these cells and direct them to damaged areas.

This is what Slack and her team are hoping to do.

“We know that as we get older, neurogenesis slows down,” explains Slack, a professor in the Department of Cellular and Molecular Medicine at the University of Ottawa. “We generate fewer and fewer new cells, and this may contribute to memory loss and impaired brain function in the elderly. On the other hand, we also know that things like exercise increase the rate of neurogenesis. So there’s obviously several mechanisms, some signals, which are encouraging new cells to form, or at least ‘slowing down the slowing down.’”

“In cases like stroke, we see new brain cells migrating to areas where there’s damage, but it’s just not happening fast enough,” adds Slack. “If we can unlock the mechanisms that control neurogenesis, we can probably speed up recovery for stroke victims and improve treatment for diseases like Alzheimer’s and Parkinson’s.”

Adult neurogenesis in humans was first discovered in the late 1990s in the hippocampus, an area of the brain involved in learning and memory. There is also some evidence of new neurons being generated in the cerebral cortex, the part of the brain responsible for thinking, perceiving and understanding language.

All of these new neurons are born not from mature brain cells, but rather from neural stem cells that remain in our brains throughout life. Stem cells are unspecialized cells that have the remarkable ability to develop into virtually any kind of cell type, including specialized brain cells.

“We’re looking at the proteins that control stem cells in the brain, and in turn the genes that produce those proteins,” says Slack. “The idea is that these proteins not only regulate the rate at which stem cells develop into mature brain cells, but also the rate at which stem cells replenish themselves.”

Although her research is cutting edge, Slack has been studying neurogenesis for more than 20 years. As a graduate student, she looked at tumour cell differentiation, the process by which these cells become more specialized— similar to how stem cells develop into specialized cells such as brain cells. For over 15 years, she has also been studying how cell cycle proteins affect the development of the embryonic brain.

Today, she is part of an interdisciplinary team at the Centre for Stroke Recovery, the only centre in the world that focuses purely on stroke recovery. Located at the Ottawa Hospital campus, the Centre is a partnership between the University of Ottawa, the Heart and Stroke Foundation, the Ottawa Hospital Research Institute and three other Canadian research centres.

“You can’t really predict how quickly our research will spin into a treatment for stroke, Alzheimer’s or Parkinson’s,” Slack explains. “What I do know is that if we don’t work on this, we’ll never solve the problem.”

Along with her research into neurogenesis, Slack also acts as the assistant dean of Graduate and Postdoctoral Studies in the Faculty of Medicine and was an associate editor of the The Journal of Neuroscience. She also serves on several review panels for research funding agencies and foundations and supervises eight graduate students and several postdoctoral fellows.

Despite her many roles, Slack’s number one passion and focus is research. “It’s so exciting, seeing new things and discovering the unexpected,” she says. “I have students who work into the night because they just can’t wait until the next day to see what’s going to happen next.

“It’s hard work, but it’s important work and so motivat­ing. I love the sense that I might be able to make a differ­ence to people’s lives in the future.”

by Leah Geller

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