Jefferson Scientists Show Human Neural Stem Cells Can Become Dopamine-Making Brain Cells in the Laboratory

Biologists at the Farber Institute for Neurosciences at Thomas Jefferson University have shown for the first time in the laboratory that they can convert some adult human neural stem cells to brain cells that can produce dopamine, the brain chemical missing in Parkinson’s disease. If the researchers can better understand the process and harness this ability, the work may someday lead to new strategies in treating neurodegenerative diseases such as Parkinson’s.

Developmental biologist Lorraine Iacovitti, Ph.D., professor of neurology at Jefferson Medical College of Thomas Jefferson University in Philadelphia, is searching for ways to convert stem cells into dopamine-making neurons to replace those lost in Parkinson’s. In previous work, she and her co-workers showed that mouse neural stem cells placed in rats with Parkinson’s disease could develop into brain cells that produced tyrosine hydroxylase (TH), the enzyme needed to make dopamine.

Dr. Iacovitti, who also is associate director of the Farber Institute for Neurosciences at Jefferson, wanted to see if human neural stem cells could become dopamine-producing brain cells as well. She and her colleagues grew neural stem cells in a laboratory dish. Using a cocktail of protein growth factors and nutrients, the researchers found they could coax approximately 25 percent of the stem cells to make TH in the dish, proving the stem cells had the capacity to manufacture dopamine. What’s more, when they removed the growth factor-cocktail, the cells continued to produce the enzyme. She reports her team’s findings November 5 at the annual meeting of the Society for Neuroscience in Orlando.

“We have two examples of human stem cells that do this,” she says. “The obvious extension [of these results] is to take those predifferentiated human dopamine neurons and transplant then into Parkinson’s disease model systems.”

But first, Dr. Iacovitti would like to purify these neurons. Her group has developed ways of tagging live dopamine neurons with a fluorescent marker, she says, “enabling us for the first time to purify or enrich the number of dopaminergic neurons and transplant them into Parkinsonian animal models.”

Ultimately, she says, they hope to one day be able to develop this as a treatment for Parkinson’s disease in people.