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Satellite Cell Exploration

A visit with Dawn Cornelison, Assistant Professor of Biological Sciences

By Noelle Buhidar
Published: - Topics: biology stem cells muscle neuromuscular disease mouse

After more than a year of rigorous research without promising results, Dawn Cornelison considered quitting graduate school. “I wanted to just go home, go to medical school, and be a doctor,” says Cornelison. But her husband provided a verbal antidote to her frustration: “You can’t quit; you have to keep going. Because of you, someday, some mother isn’t going to have to cry.” His words reminded Cornelison of the value of her research, and with a replenished feeling of motivation, she went back to the lab and has been there ever since.

Now, as an assistant professor of Biological Sciences, Cornelison specializes in the area of cellular, molecular, and developmental biology. She has dedicated over a decade to the study of muscle regeneration. Her research focuses on the behavior of a group of adult stem cells known as satellite cells. A stem cell’s job is to make more cells for such bodily tissues as skin, blood, intestinal lining, and muscle.

Tiny and uncommon within muscle tissue, satellite cells are not in active communication with each other, or anything else, unless muscle is damaged due to disease, injury, or exercise. In undamaged muscle, satellite cells are quiescent; that is, they don’t undergo cell division. In response to an injury, satellite cells are activated. Like your reaction to an alarm clock’s earsplitting ring, the satellite cells are jolted from their dormant state into a chaotic world. “So these cells wake up into what’s got to be a really noisy place because it’s just been damaged,” explains Cornelison. “There are the insides of the broken muscles, and maybe some broken nerves and blood vessels,” she adds, “so this cell wakes up, and there’s no cell like it nearby. It’s got to decide what its situation is and what it’s supposed to do about it.”

The phenomenon behind satellite cells is their ability to stir from their usual quiescent state and then adequately divide, differentiate, and fuse to restore muscle. How do satellite cells translate the array of stimuli they come across and integrate them into cell activity? Cornelison’s research strives to answer this principal question.

Though Cornelison’s lab conducts research on mouse and dog models, the ultimate goal is to understand how satellite cells function in humans. The lab uses mouse models because, as mammals, “they’ve got muscles, cells, and genes that are sufficiently similar to humans.” Thanks to advances in technology, the lab is able to ask bigger, more complicated, and more precise questions. For example, one of her students is taking time-lapse movies of mouse muscle fiber. “We can see the cells running around on the surface of the fiber and talking to each other,” says Cornelison. “We can watch them differentiate. If we fix them and poke holes in them, we can use antibodies to see what genes they are expressing, what proteins they have, and in what places.”

If she deciphers the mechanics behind muscle regeneration, Cornelison's work might someday lead to new treatments for muscle regeneration deficits in diseases such as Duchenne’s Muscular Dystrophy and aging. Already, her lab has come up with crucial findings, for instance that satellite cells from a dog dying of muscular dystrophy look exactly like cells from a healthy dog if you take them out of the muscle. This discovery means that it isn’t a deficit in the satellite cells that causes aging and disease — it’s the environment. “This really interests us,” explains Cornelison, “because our whole plan is that satellite cells’ responses to their environment is what are most important.”

Ideally, her research will give scientists insight into how to counteract the effects of aging, muscular dystrophy, and other neuromuscular diseases. “The idea that it’s not the satellite cells that are actually going bad in dystrophy could be a big break from the way we are currently trying to treat it,” says Cornelison. “So this research is important for understanding how our bodies work and how our muscles are able to replace themselves appropriately in time and magnitude.” Hopefully, in time her work will help other scientists formulate better cures.

Cornelison has come a long way from her days as a discouraged graduate student, and she has encouraging words to lend to others engaged in complex studies: “If you’re going to do research, you must have a very high tolerance for delayed gratification.” When asked about her feeling toward her work, she smiles: “I wouldn’t be doing anything else, regardless of whatever challenges might come up. To get to work with the people I do, to get to think about cool stuff all day, to think of ways to figure out new cool stuff;” as she concludes, “ I love my life.”