Medicine at Michigan-

Sue O’Shea
Photo: D.C. Goings

Sue O’Shea is an outspoken advocate for the importance of embryonic stem cells in research. She works with colonies of mouse embryonic stem cells, which she has maintained in culture since the early 1990s when she was a graduate student at Cambridge University in the United Kingdom. Recently she became the U-M’s first scientist to work with one of the human embryonic stem cell lines approved by the Bush Administration for use in federally funded research.

“Embryonic stem cells are difficult to handle,” O’Shea acknowledges. “They’re picky and caring for them is an art. Cell lines have to be divided or fed specific growth factors every day, including holidays and weekends, to keep them from differentiating.”

But O’Shea maintains that embryonic stem cells have many advantages over adult stem cells, which makes them worth the extra time and trouble. “If you want to learn about how an embryo develops or how cells differentiate, you have to use embryonic stem cells. Adult cells develop too late in the process. Adult stem cells have some plasticity, or the ability to change into other types of cells, but we don’t know how far it goes. Plus, embryonic stem cells grow much faster in culture and we need to grow large numbers of them, so we can learn how they work.”

As a child, O’Shea loved to dissect the fish her father caught, so she could examine the brain. Now graduate students in O’Shea’s laboratory are using mouse and human embryonic stem cells to model early neural system development. “The nervous system is clearly the most interesting aspect of development,” she says.

Theresa Gratsch
Photo: Bill Wood

One of her goals is to develop a library of “designer neuron” human stem cell lines for transplantation after spinal cord injuries or in neurodegenerative disease. By inserting genes called noggin and chordin into embryonic stem cell DNA, O’Shea has triggered embryonic stem cells to begin differentiating into primitive neurons. “It has just not been possible to study an equivalent early stage of neural development in humans before,” O’Shea says.

It took Theresa Gratsch, a research investigator in the O’Shea lab, nearly one full year to find the best way to get the noggin gene into stem cell DNA. “We have learned that noggin is a powerful neural inducer,” Gratsch says. “Ninety percent of stem cells transfected with noggin begin differentiating into primitive neurons as early as one day after treatment.”

Also:

Unlocking the Secrets of Stem Cells

A Stem Cell Glossary