A new technique is letting scientists study the exact way two brain cells interact.
The work focuses on myelin, the fatty insulator that enables communication between nerve cells. Cellular interactions that trigger the production of myelin are especially hard to pinpoint.
That’s because the crucial point of contact between two types of cells, the connection between axons, along which nerve impulses travel, and glial cells, which support neurons, is essentially hidden.
M. Laura Feltri, a professor of biochemistry and neurology in the University at Buffalo’s Jacobs School of Medicine and Biomedical Sciences, explains:
“Myelin is made by a glial cell wrapping around an axon cell. To study myelin, you really need to study both cells.
The glial cell wraps like a spiral around the axon, so every time you try to study the region of contact between the two cells, you end up studying the whole combination. It’s very hard to look just at the interface.”
And studying this interface is critical in certain diseases, she adds, such as Krabbe Leukodystrophy, an inherited fatal disorder.
“In Krabbe’s, for example, the problem is not just that there isn’t sufficient myelin, but that the glial cell is not providing proper support to the neuron. But to figure out exactly what’s going wrong, we needed a better way to study that interface.”
The new technique for achieving this involves using the second cell (the neuron) as a trigger to attract the first cell (the glial cell). The researchers use a system with two chambers, separated by a membrane.
“When the cells in the upper chamber ‘recognize’ the cells in the bottom chamber, they kind of ‘reach’ through the holes in the membrane for each other and touch. That is the intersection that we can then isolate and study,” Feltri says.
Using this technique, the researchers discovered novel proteins at that intersection called prohibitins, which, they found, are necessary for the production of myelin.
The discovery will help improve the understanding of and development of new treatments for myelin diseases. It also will make it easier to study all kinds of cellular interactions, not just those in the brain.
“Using this method, we can isolate the portion of a cell that comes in contact with another cell, and analyze all the proteins that are present only in this subcellular fraction,” Feltri says. “It provides a glimpse into the social life of cells.”
M. L. Feltri, et al.
Spatial mapping of juxtacrine axo-glial interactions identifies novel molecules in peripheral myelination
Nature Communications 6, Article number: 8303 doi:10.1038/ncomms9303
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