Live imaging study sheds light on myelination
Taking advantage of the optical transparency of zebrafish, researchers have imaged the dynamic signalling activity that regulates myelination in the living animal.
It has long been known that the majority of axons in our central nervous system are surrounded and insulated by a fatty substance called myelin that is produced by glial cells, called oligodendrocytes. Disruption to myelin is associated with numerous diseases of the nervous system, including multiple sclerosis, but despite its importance, how myelin is formed and how it is wrapped around our axons has remained unclear.
Researchers at the University of Edinburgh have for the first time directly visualised signals that regulate myelination in a living animal. Using embryonic zebrafish, which are optically transparent, and a genetically encoded fluorescent indicator of a specific cell signal, researchers visualised the dynamic activity of calcium in myelin sheaths as they form and mature.
This dynamic imaging analyses revealed that calcium regulates different stages of myelination through distinct signalling modes, and helped researchers identify a new molecular pathway that controls which of our axons are myelinated and which are not. Future studies will investigate whether calcium and its associated pathways might also influence the regeneration of myelin.
This study highlights how being able to directly observe the dynamic activity of our myelin-producing glial cells as the brain develops can lead to the discovery of new and unexpected mechanisms that may help us understand how to regulate myelination and promote myelin repair in humans.