Researchers at Upstate Medical University have identified a key mechanism that helps determine the length of myelin, the protective coating that surrounds many nerve fibers and allows signals to travel efficiently through the nervous system.
The findings, published this month in PLOS Biology, provide new insight into how the brain and spinal cord organize the intricate wiring of the nervous system.
Myelin is produced by specialized cells called oligodendrocytes. It wraps around nerve fibers, or axons, much like insulation around an electrical wire. The length of these myelin segments varies throughout the nervous system and influences how quickly nerve signals travel.
Myelin sheaths are important to just about everything we do. If myelin is damaged and lost (for example, in multiple sclerosis), signaling between neurons becomes disrupted and the support to maintain neuronal health is lost. This leads to devastating symptoms related to body control, fatigue, vision, thinking, movement, and more.
"Numerous neurological conditions across our lifespan disrupt oligodendrocyte cells and the myelin sheaths they form," said the study's senior author, Marie Bechler, PhD, assistant professor of cell and developmental biology, and neuroscience and physiology. "Our research aims to understand the impact of these changes compared to the healthy nervous system as well as to find ways to promote myelin sheath growth in diseases where myelin is lost or damaged."
For decades, researchers have known that thicker nerve fibers tend to have longer myelin segments. What has remained unclear is how the cells that produce myelin detect the size of a nerve fiber and use that information to determine how much myelin to make.
The Upstate-led study identifies a key part of that process: a protein called Piezo1.
The researchers found that oligodendrocytes use Piezo1 to sense the diameter of the nerve fibers they are wrapping. That information helps determine the length of each myelin segment.
The study also found that Piezo1 appears to play an especially important role during the early stages of myelin formation, when oligodendrocytes are actively building and extending the myelin sheath.
The findings help explain how the nervous system establishes precise patterns of myelin along its nerve fibers. Because myelin influences the speed and efficiency of nerve signaling, understanding how its structure is controlled could provide a foundation for future research into disorders involving myelin and nerve function.
The study was conducted by a team of Upstate Medical University researchers in the Becher lab, with part of the study assisted by the Electron Microscopy core. This work was published with recent PhD graduate Amanda R. Young as first author; Bechler served as senior author.
