Mitochondria in Myelinating Oligodendrocytes: Slow and Out of Breath?

Niklas Meyer,Johanne Egge Rinholm

doi:10.3390/metabo11060359

Niklas Meyer, Johanne Egge Rinholm

Open Access

https://doi.org/10.3390/metabo11060359

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Journal: Metabolites	Publication Date: Jun 5, 2021
Citations: 34	License type: CC BY 4.0

Affiliation: Oslo University Hospital, University of Oslo

Abstract

Myelin is a lipid-rich membrane that wraps around axons and facilitates rapid action potential propagation. In the brain, myelin is synthesized and maintained by oligodendrocytes. These cells have a high metabolic demand that requires mitochondrial ATP production during the process of myelination, but they rely less on mitochondrial respiration after myelination is complete. Mitochondria change in morphology and distribution during oligodendrocyte development. Furthermore, the morphology and dynamic properties of mitochondria in mature oligodendrocytes seem different from any other brain cell. Here, we first give a brief introduction to oligodendrocyte biology and function. We then review the current knowledge on oligodendrocyte metabolism and discuss how the available data on mitochondrial morphology and mobility as well as transcriptome and proteome studies can shed light on the metabolic properties of oligodendrocytes.

Highlights

Myelin is a lipid-rich membrane that wraps around axons and facilitates rapid action potential propagation
Oligodendrocytes have a large network of tubular mitochondria that are important for ATP production and Ca2+ signaling to stimulate differentiation and growth of the myelin sheath
Mature oligodendrocytes have fewer and more fragmented mitochondria. This change in mitochondria is linked to a shift toward more glycolysis and less oxidative phosphorylation (OXPHOS), and mature oligodendrocytes release lactate from the myelin sheath to underlying neurons

Summary

Oligodendrocytes—The Myelin Forming Glia Cells of the Brain

Astrocytes are the most abundant glial cell group with a myriad of interactions. Via their processes, they interact with all kinds of CNS cell types while providing metabolic support to neurons, recycling of neurotransmitters, spatial potassium buffering after neuronal activity, or help in the formation of the blood–brain barrier. The majority of OPCs differentiate into oligodendrocytes, they are able to form astrocytes and neurons [4]. Mature oligodendrocytes are the myelin forming cells of the CNS. Oligodendrocytes are much more abundant in the human than the murine brain, where they have been studied more extensively. Oligodendrocyte health and function is increasingly appreciated and studied

Oligodendrocyte Maturation and Myelin Formation

Developing Oligodendrocytes Have Active Mitochondrial Respiration

Oligodendrocyte Mitochondrial Load and OXPHOS Is Reduced after Myelination

Mitochondria in the Myelin Sheath

Mitochondrial Mobility in Oligodendrocytes

Findings

Conclusions