MiNDS High School Co-op Program

AUTHORS: Siu C, Balsor J, Jones D, Murphy K

Summary: Caitlin Siu

Myelin is typically thought of as insulation, but recent studies show it also plays roles in neuroplasticity, axonal metabolism, and neuroimmune signalling. Myelin is complex, and composed of many proteins, with Myelin Basic Protein (MBP) being the most studied. MBP has 2 families: Classic-MBP, necessary for activity-driven compaction of myelin around axons; and Golli-MBP, found in neurons, oligodendrocytes, and T-cells, called a “molecular link” between the nervous and immune systems. In visual cortex, myelin proteins interact with immune cells to affect experience-dependent plasticity. We studied myelin in human visual cortex using Western blotting to quantify Classic- and Golli-MBP expression in post-mortem samples ranging from 20 days to 80 years old. We found that Classic- and Golli-MBP have different patterns of change across the lifespan. Classic-MBP increases up to 42 years and then declines into aging. Golli-MBP has early developmental changes that coincide with milestones in visual system sensitive period, and gradually increases into aging. There are three stages in the balance between Classic- and Golli-MBP expression, with Golli-MBP dominating early, then shifting to Classic-MBP, and back to Golli-MBP in aging. Golli-MBP has a wave of high inter-individual variability during childhood. These results are timely because they complement recent advances in MRI techniques that produce high resolution maps of cortical myelin in normal and diseased brain. The pattern of Golli-MBP across the lifespan suggests it supports high neuroimmune interaction in cortical development and in aging.