The cerebrospinal fluid (csf) that bathes the brain and spinal cord may play a larger role in the developing brain than previously thought, say researchers at Children’s Hospital Boston. A paper published online March 10 in Neuron indicates how signals from the CSF help drive neural development and identifies a CSF protein whose levels are elevated in patients with glioblastoma, a common malignant brain tumor, suggesting a potential link between CSF signaling and brain tumor growth and regulation.
Using a mouse model, the study team noticed that these apical proteins are expressed on the parts of the stem cell that are in contact with the CSF, and that stem cells actually send tiny protruding processes called cilia, that act almost like antennae, directly into the CSF. They suspected that signals to initiate or curb stem cell growth were coming from the CSF. But how? The team showed that Igf2 levels in CSF regulated the rate of stem-cell proliferation, fluctuating over time but peaking near birth, a time when the cortex is actively developing.
“The CSF is really telling the brain what to do,” says senior investigator Christopher Walsh, Bullard Professor of Pediatrics and Neurology and chief of the Division of Genetics at Children’s. “It’s telling the stem cells to either divide a lot if you’re in the embryonic brain, or if you’re in the adult brain, just rest, and we’ll tell you if we need you.”
A better understanding of this process could lead to increased understanding of some brain tumors, including glioblastoma.
Image: Jon Chase/Harvard News Office