Remodeling myelination: implications for mechanisms of neural plasticity

Abstract

One of the most significant paradigm shifts in membrane remodeling is the emerging view that membrane transformation is not exclusively controlled by cytoskeletal rearrangement, but also by biophysical constraints, adhesive forces, membrane curvature and compaction. One of the most exquisite examples of membrane remodeling is myelination. The advent of myelin was instrumental in advancing the nervous system during vertebrate evolution. With more rapid and efficient communication between neurons, faster and more complex computations could be performed in a given time and space. Our knowledge of how myelin-forming oligodendrocytes select and wrap axons has been limited by insufficient spatial and temporal resolution. By virtue of recent technological advances, progress has clarified longstanding controversies in the field. Here we review insights into myelination, from target selection to axon wrapping and membrane compaction, and discuss how understanding these processes has unexpectedly opened new avenues of insight into myelination-centered mechanisms of neural plasticity.

Oligodendroglia: metabolic supporters of neurons

“…The oligodendrocyteproduced myelin sheath is classically characterized by the existence of multiple myelin segments along the axon separated by regions devoid of myelin called nodes of Ranvier (for recent reviews see refs. [6][7][8]. Unlike their peripheral analog the Schwann cell, a single oligodendrocyte can produce multiple myelin segments on multiple axons.…”

“…Multiple studies have shown that myelin deposition is not static, but far more dynamic than initially thought, with adaptive changes in myelin driven by changes in neuronal activity (myelin plasticity) (6,(20)(21)(22)(23)(24)(25). These changes, e.g., induced by optogenetic stimulation or stimulated through learning of complex motor skills, promote oligodendrogenesis and the deposition of new myelin sheaths along the axons.…”

Antagonistic Functions of MBP and CNP Establish Cytosolic Channels in CNS Myelin

“…Previously, myelin has been regarded as an inert and purely insulating membrane, but it is now clear that myelin is metabolically active, providing support to the underlying axon (Fünfschilling et al., 2012, Lee et al., 2012, Saab et al., 2016). In addition, myelin growth in response to neuronal activity has been described, and this may contribute to information processing by modulating velocity and synchronicity of nerve impulses in neuronal networks (Fields, 2015, Chang et al., 2016). At first glance, structural dynamics seems to be incompatible with myelin consisting of multilamellar membrane with little cytoplasm (Snaidero and Simons, 2014).…”

Multiscale Modelling of Blast-Induced TBI Mechanobiology - From Body to Neuron to Molecule

“…Inputs from this mechanical model could be used to simulate axonal depolarisation (water and electrolyte shifts), hyper-metabolism needed for repolarisation, disruption to propagation of action potentials and axonal local cytotoxic micro-edema leading to formation of retraction balls. These responses may provide partial explanation of recently reported 'white matter plasticity' in mTBI [61][62][63] . Mathematical models of the mechanical deformation and damage to intraaxonal MTs and associated protein Tau have been recently reported [24][25]30,38,[64][65] .…”