University of Wisconsin scientists are the first researchers to coax human embryonic stem cells into spinal motor neurons, a feat that could eventually lead to treatment of individuals with damaged nervous systems, causing disorders such as Lou Gehrig’s disease or muscular dystrophy.
“Motor neurons control all muscles of our body,” said UW professor of anatomy and neurology and lead researcher Su-Chun Zhang. “Without these cells we could not move.”
The team of UW researchers published their results in a Jan. 30 edition of Nature Biotechnology journal as a follow-up of their 2001 published research in which the researchers coaxed embryonic stem cells into general brain stem cells.
Researchers’ goal to convert embryonic stem cells into motor neurons proved difficult, mostly due to the complex nature of motor neuron development.
Motor neurons are one of the earliest neural structures to emerge in a developing embryo, according to Zhang. Due to the narrow time frame for development, they are difficult to make, he said.
There is a critical time period in development that we could coax stem cells to transform themselves into these motor neurons, Zhang said.
“I have the utmost respect for this work,” said UW professor of ophthalmology and stem cell researcher Ronald Kalil, who researches another part of the nervous system unrelated to motor neurons. “In principle, this [research] could be [applied] for all other types of cells.”
Zhang and the other researchers accomplished their goal of motor cell production by generating neural stem cells from embryonic stem cells grown in a petri dish and then exposing the cells to many different chemical “cocktails” designed to promote growth of the motor neurons in the lab dish.
“We gave [chemical] cocktails, each at a specific time, and guided [the stem cell growth] just like you [would] raise a baby,” Zhang said. “You coach them one step at a time.”
According to a release, the key to the researchers’ success was the specific time they coached their cells to change into motor neuron cells.
Xuejun Li, an assistant scientist in Zhang’s group and the lead author of the research’s publication, decided to add a necessary chemical for growth much earlier in the neuronal stage of development than previously attempted. This was crucial to the discovery and demonstrated to researchers that the growth of human stem cells is more complex than previously thought.
Zhang said the most important outcome from his lab’s research was the new way of thinking about neural development and how human development is not exactly like animal development.
“[The research] brings up a new way of thinking about how we are going to use the stem cells,” Zhang said. “Human cells are quite different than mouse cells, and so we need to treat human cells in a very unique way.”
Zhang explained that his team of researchers originally applied knowledge from animal studies to attempt the creation of motor neuron cells, but the method did not work, and the scientists had to change the way they previously thought about development.
For now, Zhang and his lab will study how the motor neuron cells will behave in living animals, rather than in an artificial system, as they have been researching for the past few years.
“What we have learned will have an impact on changing people’s thinking of how the human brain is actually developed,” Zhang said. “This will hopefully [have an] impact on many fronts.”
