Nerve cell communication mechanisms uncovered, may lead to new therapeutic approaches for neurodegenerative diseases

Story by Madison Knapp/ Bond Life Sciences summer intern

Simple actions like walking, swallowing and breathing are the result of a complex communication system between cells. When we touch something hot, our nerve cells tell us to take our hand off the object.

This happens in a matter of milliseconds.

This hyperspeed of communication is instrumental in maintaining proper muscle function. Many degenerative diseases affecting millions of people worldwide result from reduced signaling speed or other cellular miscommunications within this intricate network.

Michael Garcia, investigator at the Christopher S. Bond Life Sciences Center and associate professor of biology at the University of Missouri, conducts basic research to answer fundamental questions of nerve cell mechanics.

“In order to fix something, you need to first understand how it works,” Garcia said.

Garcia’s research illuminates relationships between nerve cells to find factors affecting function.  His goal is to provide insight on fundamental cellular mechanisms that aren’t fully understood.

Garcia’s research has been funded partly by the National Science Foundation and National Institutes of Health.

Technological advancements have made it possible to better understand disease development in the human body to create more effective treatments. Alas, a scientist’s work is never finished— when the answer to one question is found, ten more crop up in its wake.

Garcia’s research, which appeared in several journals including Human Molecular Genetics andthe Journal of Neuroscience Research initially sought to shed light on the neuronal response to myelination, the development of an insulating border around a nerve cell, called a myelin sheath, which is critical in rapid communication between cells.

How it works: Rebuilding cell theory

Garcia’s early research disproved a long-standing hypothesis concerning this cellular feature.

Mammals’ nervous systems are uniquely equipped with myelination, which has been shown to increase conduction velocity, or the speed at which nerve cells pass signals. Low velocity is often associated with neurodegenerative diseases, so research exploring why could later have application in therapeutic technology.

In addition to myelination, cell size makes a big difference in conduction velocity — the bigger the nerve cells, the faster they can pass and receive signals. Garcia’s findings disproved a hypothesis that related myelination to this phenomenon.

The hypothesis, published in a 1992 edition of Cell, claimed that myelination causes a cellular process called phosphorylation which then causes an increase in the axonal diameter (width of the communicating part of a nerve cell), leading to faster nerve cell communication. Garcia found that myelination did cause an increase in axonal diameter, and myelination was required for phosphorylation, but that the two results were independent of one another.

To narrow in on the processes affecting axonal diameter, Garcia identified the protein responsible for growth.

Garcia followed earlier work, showing that one subunit controls whether there is growth at all with myelination, by identifying the domain of this protein that determines how much growth.

After clarifying this part of the process, a question still remains: If not to control myelination, why does phosphorylation happen?

Looking forward

Jeffrey Dale, a recent PhD graduate from Garcia’s lab, said current research is in part geared toward finding a connection between phosphorylation and a process called remyelination.

Remyelination could be key to new therapeutic approaches. When a cell is damaged (as in neurodegenerative disease) the myelin sheath can be stripped away. Remyelination is the process a cell goes through to replace the myelin.

Imagine you have a new wooden toy boat, painted and smooth. If you take a knife and whittle away all the paint and then repaint it—even exactly how it was painted before—the boat is not going to be as shiny and smooth as it was before. This is how remyelination works (or rather, doesn’t).  When nerve cells are damaged, the myelin sheath is stripped away and even after the cell rebuilds it, the cell can’t conduct signals at the same speed it was able to before.

“If you can learn what controls myelination, maybe you can improve effectiveness of remyelination,” Dale said.

Garcia said it is possible that revealing the mechanics involved in phosphorylation could lead to better treatments. In context of neurodegenerative diseases, the question why don’t axons function properly might be wrapped up in Garcia’s question: In healthy cells, why do they?

Supervising editor: Paige Blankenbuehler

Article originally published on Decoding Science.