(Santa Barbara, Calif.) Using the surface forces apparatus and an atomic force microscope, researchers at UC Santa Barbara have taken a molecular approach to myelin membrane interactions, leading to insights into demyelinating diseases, such as multiple sclerosis. Their research is published in the Proceedings of the National Academy of the Sciences.
For a healthy nervous system, axons the long projections of our nerve cells that run throughout our bodies must be properly insulated. Much like conventional power cords need electrical insulators around the conducting wires for efficient and effective transfer of current, axons rely on multiple bilayers of myelin to maintain a rapid and optimal transfer of impulses between, for instance, brain and organ, or spinal cord and muscle. These bilayers are composed of lipids (fat molecules), protein and water.
"Basically, myelin is this multiple stacking of lipid bilayers," said Dong Woog Lee, a researcher in UCSB's Department of Chemical Engineering, and the study's lead author. "They need to be compact, and with very little water between the bilayers."
However, even the slightest change in the composition of these myelin bilayers to affect their ability to insulate axons, the researchers found. To observe and measure the characteristics and differences between healthy and diseased myelin bilayers, they studied the ability of these layers to adhere to each other.
On each of the two opposing surfaces of the surface forces apparatus a highly sensitive instrument that can measure interactions between membranes the researchers deposited a lipid bilayer on a mica substrate. Then they immersed the setup in a buffer solution containing myelin basic protein (MBP), a biomolecule commonly found in myelin that gives them adhesive properties and plays a role in maintaining the optimal structure of the myelin sheath. They brought the two bilayers close together, allowing them to stick
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University of California - Santa Barbara