Chen Gu, Assistant Professor of Neuroscience at Ohio State and lead author of the study.
COLUMBUS, US: The development of a new cell-culture system that mimics how specific nerve cell fibers in the brain become coated with protective myelin opens up new avenues of research about multiple sclerosis (MS). Initial findings suggested that myelin regulates a key protein involved in sending long-distance signals.
MS has long been considered a disease of white matter, a reference to the white-coloured bundles of myelin-coated axons that project from the main body of a brain cell. But researchers have discovered that the condition also affects myelinated axons scattered in gray matter that contains main bodies of brain cells and specifically the hippocampus region, which is important for learning and memory.
Up to half of MS patients suffer cognitive deficits in addition to physical symptoms. Researchers suspect that cognitive problems are caused by abnormal electrical activities of the demyelinated axons extending from hippocampal cells, but until now have not been able to test myelin’s role in this part of the brain.
Ohio State University researchers have created a system in which two types of cells interact in a dish as they do in nature: neurons from the hippocampus and other brain cells, called oligodendrocytes, whose role is to wrap myelin around the axons.
Now that the researchers can study how myelination is switched on and off for hippocampal neurons, they also can see how myelin does more than provide insulation - it also has a role in controlling nerve impulses traveling between distant parts of the nervous system. Identifying this mechanism when myelin is present will help improve understanding of what happens when axons in this critical area of the brain lose myelin as a result of MS, researchers said.
So far, the scientists have used the system to show that myelin regulates the placement and activity of a key protein, called a Kv1.2 voltage-gated potassium cahannel, that is needed to maintain ideal conditions for the effective transmission of electrical signals along these hippocampal axons.
“This channel is important because it is what leads to electrical activity and how neurons communicate with each other downstream,” said Chen Gu, Assistant Professor of Neuroscience at Ohio State and lead author of the study. “If that process is disrupted by demyelination, disease symptoms may occur.”
The study appears in the current issue of the Jounal of Biological Chemistry.
This work was supported by a Career Transition Fellowship Award from the National Multiple Sclerosis society and a grant from the National Institure for Neurological Disorders and Stroke. Gu conducted this study with Yuanzheng Gu, a research associate in the Department of Neuroscience at Ohio State.
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