University of Rochester scientists have found a method to segregate neural stem cells from human brain tissue which brings hope of better and newer treatments for brain diseases.
It could be an important step toward developing new treatments for conditions of the nervous system, like Parkinson's and Huntington's diseases and spinal cord injury.
Neurologist Steven Goldman led the research team.
The natural stem cells can renew themselves and have the potential to become a number of brain cell types - for instance, oligodendrocytes that might help people with multiple sclerosis, or neurons to help people with Parkinson's disease.
Goldman's team found that certain classes of genes encoding for proteins active in mouse neural stem cells - such as members of the Notch and WNT families - were highly active.
But when the scientists looked more closely, they found that the freshly isolated neural stem cells expressed some genes from these families that were previously virtually unknown in humans, and which had never before been implicated in human brain function.
At the same time, some of the genes that are important and active in mouse neural stem cells proved not to be so in the human cells.
"While the general signaling pathways active in mice and people are very similar, the individual genes are quite different. This is not something we would have predicted. It's a good demonstration that you can't use mouse studies to fully dictate what kinds of therapeutics should be used in people," said Goldman.
The new technology is built around a piece of DNA that codes for a protein known as Sox2, which has long been recognized as a key stem cell gene. Since the gene is active only in stem cells, finding a way to see and isolate cells with an active Sox2 gene is the key.
To track it down, the team identified the DNA sequence, known as an enhancer that determines whether Sox2 is active in neural stem cells. The scientists took that piece of DNA, coupled it to a gene that makes cells emit light of a particular wavelength, and then packaged the resulting synthetic DNA into a virus.
They used the virus to deliver the synthetic DNA to neural stem cells in the brain tissue. The technique compelled neural stem cells - and only the stem cells - to emit light of a certain color, which in turn allowed a laser-based system to tag and capture just those cells.
The study was published in the Journal of Neuroscience.