Human skin cells were successfully converted into the specific types of brain cells affected by Huntington's disease.
A research team demonstrated these cells were able to survive for six months after they were injected into the brains of mice, and behaved similarly to the native cells, the Washington University in St. Louis reported.
"Not only did these transplanted cells survive in the mouse brain, they showed functional properties similar to those of native cells," said senior author Andrew S. Yoo, PhD, assistant professor of developmental biology. "These cells are known to extend projections into certain brain regions. And we found the human transplanted cells also connected to these distant targets in the mouse brain. That's a landmark point about this paper."
The brain cells in question are called medium spiny neurons, which control movement. These cells highly affected by Huntington's disease, which is a genetic disorder that causes involuntary muscle movement and eventual cognitive decline.
To reprogram the vital cells the researchers put the human skin cells in an environment that mimics that of brain cells. In past studies the team had found small molecules of RNA have the ability to transform skin cells into a variety of neurons by revealing DNA that is "packed away." The researchers have also tailored chemical signals to expose cells to additional molecules, dubbed "transcription factors."
"We think that the microRNAs are really doing the heavy lifting," said co-first author Matheus B. Victor, a graduate student in neuroscience. "They are priming the skin cells to become neurons. The transcription factors we add then guide the skin cells to become a specific subtype, in this case medium spiny neurons. We think we could produce different types of neurons by switching out different transcription factors."
The new cells were found to look and behave exactly like medium spiny neurons. These converted allowed cells to express genes specific to spiny neurons. In the future the researchers plan to inject these converted cells into the brains of mice with a model of Huntington's disease to see if it affects symptoms.
The findings were published Oct. 22 in the journal Neuron.
