So far, the scientists have used the system to show that myelin regulates the placement and activity of a key protein, called a Kv1.2 voltage-gated potassium channel, that is needed to maintain ideal conditions for the effective transmission of electrical signals along these hippocampal axons.
"This channel is important because it is what leads to electrical activity and how neurons communicate with each other downstream," said Chen Gu, assistant professor of neuroscience at Ohio State and lead author of the study. "If that process is disrupted by demyelination, disease symptoms may occur."
The study appears in the current (July 22, 2011) issue of the Journal of Biological Chemistry.
To create the cell culture system, the researchers began with hippocampus neurons from a rodent brain a cell type that Gu has worked with for years. In culture, these cells can grow and develop dendrites other branch-like projections off of neurons and axons as well as generate electrical activity and synaptic connections, the same events that occur in the brain.
The researchers then added oligodendrocytes, along with some of their precursor cells, to the same dish as the neurons. And eventually, after maturing, these oligodendrocytes began to wrap myelin around the axons of the hippocampal neurons.
This system takes about five weeks to create, but the trickiest part, Gu said, was developing the proper solution for this culture so that both kinds of cells would behave as nature intended.
"In the end, the composition of the culture medium is basically half from a solution that supports the neurons and half from a medium in which the oligodendrocytes function well. We know that all the cells were happy because we got myelin," said Gu, also an investigator in Ohio State's Center for Molecular Neurobiology.
With the system established, they then turned to experimentation to test
|Contact: Chen Gu|
Ohio State University