"Astrocytes are definitely much more than support cells in the brain," said Kim Tieu, Ph.D., a corresponding author of the paper and assistant professor in the Department of Environmental Medicine at the University of Rochester Medical Center. "Scientists are discovering their involvement in many diseases. The latest results point to their role in Parkinson's disease."
Tieu initiated the study while a post-doctoral research associate in the laboratory of Serge Przedborski, M.D., Ph.D., the Page and William Black Professor of Neurology at Columbia University and a corresponding author. They chose to study how the brain handles a chemical known as MPTP, which ultimately damages the exact same brain cells that are injured in patients with Parkinson's disease. While MPTP does not cause Parkinson's disease, scientists regularly use it as a model for the disease because it causes an identical type of brain damage.
In the brain, MPTP is converted primarily in astrocytes to a chemical called MPP+, which is deadly to dopamine neurons. More than 20 years ago, as a graduate student with Solomon Snyder, M.D., Jonathan Javitch, M.D., Ph.D., now professor of psychiatry and pharmacology at Columbia and an author on the current paper, concluded that MPP+ is released from astrocytes before it kills dopaminergic neurons. But exactly how MPP+ is freed from astrocytes was unknown.
In this week's PNAS paper, the scientists finger oct3 as the shepherd that escorts toxic MPP+ out of the astrocytes and into the space surrounding dopamine neurons. That's where another molecule known as the dopamine transporter picks it up and brings it into the neuron itself.
When the team blocked or genetically removed oct3 in mice, the dopamine neurons in the brains di
|Contact: Tom Rickey|
University of Rochester Medical Center