Brain cell insulators are short-timers

Limited myelin production time may make it harder to repair nerve casings damaged by multiple sclerosis

SHORT-TIMER CELLS Cells called oligodendrocytes (shown in green) only spend five hours insulating nerve fibers (purple) with a waxy coating of myelin in the zebrafish central nervous system.

T. Czopka et al/Developmental Cell 2013

Cells that sheathe the brain’s electrical wires in a protective coating called myelin have a brief career, a new study of zebrafish finds.

Specialized brain cells known as oligodendrocytes wrap myelin around axons, long fibers that carry electrical messages between nerve cells. After only five hours, the cells bow out of the myelin production business, researchers from the University of Edinburgh report in the June 24 Developmental Cell.

Myelination is crucial for brain function, and when it breaks down, so does communication among brain cells. The new results could influence treatment strategies for diseases such as multiple sclerosis, which damages myelin. Instead of coaxing existing cells to replenish myelin, doctors may need to stimulate new oligodendrocyte growth in patients’ nervous systems.

In the new study, researchers made time-lapse movies of neural development in zebrafish by tagging electricity-generating neurons and myelin-making oligodendrocytes in the fishes’ spinal cords with different colors. A protein called Fyn kinase stimulates oligodendrocytes to produce more myelin sheaths for the first five hours of the cells’ existence, but the protein can’t persuade the cells to postpone retirement, the researchers discovered.

Tina Hesman Saey

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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