Point Loma A UC San Diego-led research team has invented a shortcut to turning skin cells into brain cells, a method that may one day be of use in treating neurodegenerative diseases, such as Parkinson's, Huntington's and Alzheimer's.
The team created functional neurons from skin cells by blocking production of a single protein. The method bypasses existing techniques that make neurons from stem cells derived from skin cells, a complicated process.
The researchers found that the protein, called PTB, stops the activity of neuronal genes in non-neuronal cells. When PTB is blocked, the neuronal genes are activated, and functional neurons can be produced. The study was performed with cell cultures.
Neurodegenerative diseases are caused by defects in certain neurons. In Parkinson's, neurons stop producing a chemical called dopamine needed for movement. Transplantation of fresh neurons could cure the disease, or at least relieve symptoms for many years.
Earlier attempts to treat Parkinson's patients with dopamine-producing neurons taken from aborted fetuses have produced mixed results. Scientists such as Jeanne Loring of The Scripps Research Institute say producing neurons from stem cells should be more effective, because neurons of more uniform quality can be made.
Direct conversion of skin cells to neurons would take less time than using stem cells as an intermediary, and might be potentially safer. But before this approach can be tried in people, years of study, including animal testing, will be needed to ensure the method's safety and effectiveness.
The study was published in the journal Cell. Its senior author is Xiang-Dong Fu, professor of cellular and molecular medicine at UC San Diego. Its first author is Yuanchao Xue of Wuhan University in China.
Direct conversion of skin cells to neurons has been done before by adding a variety of chemicals, the study said. The new method provides the advantages of targeting the activity of just one chemical, namely the protein, along with superior efficiency in converting the cells.
Researchers are now focusing on using stem cells of various types to make the neurons. One approach is to make induced pluripotent stem cells, or IPS cells, from skin cells called fibroblasts.
These IPS cells act like human embryonic stem cells, which can become nearly any cell in the body, a state called pluripotency. IPS cells are easier to get than embryonic stem cells and don't involve the moral objections many have to working with such cells, derived from human embryos.
Three stem cell researchers not involved with the study described it as interesting science that if validated, could eventually give another option for therapy.
Loring, who heads The Center for Regenerative Medicine at The Scripps Research Institute, said the new study represents basic research that is a long way from clinical use.
"This is interesting fundamental research but direct conversion of fibroblasts to neurons, which has been done in a number of ways, is a long way from practical use as a therapy," Loring said in an email.
Loring and her colleagues are researching a therapy for Parkinson's patients that employs a patient's own fibroblasts to generate IPS cells, which are then turned into neurons.