|Ulrich Mueller, Ph.D., is a professor and director of the Dorris Neuroscience Center at the Scripps Research Institute.|
Scientists at Scripps Research Institute in La Jolla have found a previously unknown type of stem cell in the brain. This one forms the nerves that make up the outer layers of the brain – those layers called the cortex that specifically carry out our higher reasoning.
Until now, the thinking had been that all of the brain’s cells come from a single group of stem cells. This distinction could prove important for developing therapies based on stem cells. Whether a therapy is attempting to inject new stem cells into the brain or manipulate the cells that are already there, the scientists need to know that they are working with the right stem cell.
Up until now, researchers trying to reproduce human cortical neurons in the lab from stem cells have only generated lower-layer-type neurons. “This opens a door now to try to make the upper-layer neurons, which are frequently affected in psychiatric disorders,” said Mueller.
Studies like this one highlight how much there is still to learn about how stem cells build our bodies during development and maintain organs as adults. Developing stem cell-based therapies isn’t a matter of just injecting a stem cell into the damaged organ and hoping for the best. Scientists need to use the right kind of stem cell for each task.
When we interviewed Lawrence Goldstein about Alzheimer’s disease recently he had a great analogy for why scientists can’t just inject any old stem cell into the brain as a “cure” for disease. He pointed out that an iPhone’s mechanics are made of metal, but if your iPhone breaks, you don’t just inject a bunch of metal into the phone. You have to open it up and put the right kind of metal in the right places to fix the specific problem.
This study from Scripps brings scientists one step closer to knowing which is the right kind of metal (or stem cell) to fix disorders like Alzheimer’s disease and autism, which involve the outer brain regions that arise from the newly identified stem cells.
CIRM funding: Santos Franco (TG2-01165)
Santos J. Franco, Cristina Gil-Sanz, Isabel Martinez-Garay, Ana Espinosa, Sarah R. Harkins-Perry, Cynthia Ramos, and Ulrich Müller (2012). Fate-Restricted Neural Progenitors in the Mammalian Cerebral Cortex Science DOI: http://www.sciencemag.org/content/337/6095/746