June 7, 2012 -- A team of scientists has discovered what could be a novel source for researching and potentially treating Alzheimer's disease and other conditions involving the destruction of brain cells.
Researchers at the University of California San Francisco-affiliated Gladstone Institutes converted skin cells from mice and humans into brain stem cells with the use of a protein called Sox2. Using only this protein to transform the skin cells into neuron stem cells is unusual. Normally, the conversion process is much more complex.
Neuron stem cells are cells that can be changed into the nerve cells and the cells that support them in the brain. The neuronal stem cells formed in this study are unique because they were prepared in a way the prevented them from becoming tumors, which is what often happens as stem cells differentiate, explained David Teplow, professor of neurology and director of the Easton Center for Alzheimer's Disease Research at UCLA. Teplow was not involved in the study, but is familiar with this type of research.
These immature brain stem cells then developed into different types of functional brain cells, which were eventually able to be integrated into mouse brains.
The idea that these cells can become fully functioning brain tissue is significant, the authors explained, because by becoming part of the brain, the cells can replace the cells killed off by the disease process.
These cells also offer a potential way to learn about the mechanisms behind neurodegenerative disorders as well as lead to research into new drugs, explained Dr. Yadong Huang, a study co-author and associate investigator at the Gladstone Institute of Neurological Disease.
"The next step is, we are trying to get these skin cells from patients with this disease so we can reprogram and convert the diseased cells into these neuron stem cells and develop those into neurons in culture," he said.
After that, researchers can study how these diseases develop based on what's observed in culture dishes.
"It's really hard to get neurons from human brains for research, and now, we can generate them," Huang said. "Secondly, we can do some drug screening. If we have patient-specific neurons in culture, we can test some or develop some drugs to see how they work on these neurons."
These neuron stem cells, Huang explained, also don't develop into tumors as other types of stem cells are prone to do.
"This is a significant step forward," said Teplow. "Thus far, the challenges with stem cells have been to make the right cells and also be able to make a cell preparation where the risk of having cells that can form tumors is low." Teplow was not involved in Huang's study.
There are still a number of steps this area of research must undergo determining whether these cells can really replace lost brain cells, but experts are encouraged.
"One of the target areas of the brain in Alzheimer's disease is the hippocampus, where there is tremendous loss of neurons, and there is also loss in the outer part of the brain as it progresses," Teplow said. "If we can introduce these cells into these two areas to replenish cells that are lost, we can theoretically reverse the disease."