Unraveling Myelin Plasticity.

Giulia Bonetto,Ragnhildur Thóra Káradóttir,Yasmine Kamen,Kimberley Anne Evans

doi:10.3389/fncel.2020.00156

Abstract

Plasticity in the central nervous system (CNS) allows for responses to changing environmental signals. While the majority of studies on brain plasticity focus on neuronal synapses, myelin plasticity has now begun to emerge as a potential modulator of neuronal networks. Oligodendrocytes (OLs) produce myelin, which provides fast signal transmission, allows for synchronization of neuronal inputs, and helps to maintain neuronal function. Thus, myelination is also thought to be involved in learning. OLs differentiate from oligodendrocyte precursor cells (OPCs), which are distributed throughout the adult brain, and myelination continues into late adulthood. This process is orchestrated by numerous cellular and molecular signals, such as axonal diameter, growth factors, extracellular signaling molecules, and neuronal activity. However, the relative importance of, and cooperation between, these signaling pathways is currently unknown. In this review, we focus on the current knowledge about myelin plasticity in the CNS. We discuss new insights into the link between this type of plasticity, learning and behavior, as well as mechanistic aspects of myelin formation that may underlie myelin plasticity, highlighting OPC diversity in the CNS.

Highlights

In the central nervous system (CNS), myelin is produced by oligodendrocytes (OLs) that differentiate from oligodendrocyte precursor cells (OPCs) (Fields, 2014)
Whereas, altering amino-3-hydroxy-5-methyl-4isoxazolepropionic acid receptors (AMPARs) receptors, postnatally, during the peak of the myelination period increased OPC proliferation while reducing their differentiation (Chen et al, 2018), suggesting that modifying receptor properties at specific timepoints can alter OPC dynamics. These studies indicate that glutamate signaling through AMPA/kainate receptors (KARs) and N-methyl-D-aspartate receptors (NMDARs) depends on a complex interplay of factors, such as the receptor subtype and density, the frequency, the amount, and probability of glutamate release from active neurons
In zebrafish, two populations of OPCs were identified in the spinal cord: a population that mostly proliferates in response to activity, but does not differentiate, and a second population arising from the first one, which differentiates into myelinating OLs

Summary

Unraveling Myelin Plasticity

Giulia Bonetto1†, Yasmine Kamen1†, Kimberley Anne Evans and Ragnhildur Thóra Káradóttir1,2*. Plasticity in the central nervous system (CNS) allows for responses to changing environmental signals. OLs differentiate from oligodendrocyte precursor cells (OPCs), which are distributed throughout the adult brain, and myelination continues into late adulthood. This process is orchestrated by numerous cellular and molecular signals, such as axonal diameter, growth factors, extracellular signaling molecules, and neuronal activity. We focus on the current knowledge about myelin plasticity in the CNS. We discuss new insights into the link between this type of plasticity, learning and behavior, as well as mechanistic aspects of myelin formation that may underlie myelin plasticity, highlighting OPC diversity in the CNS

INTRODUCTION

THE DIFFERENTIAL PATH OF MYELINATION

Glutamate signaling

OPC HETEROGENEITY

Diverse proliferation and differentiation potential

Cognitive functions Social behavior Sensory experience

OUTLOOK AND FUTURE PERSPECTIVE