Myelination plays an important role in cognitive development and in demyelinating diseases like multiple sclerosis (MS), where failure of remyelination promotes permanent neuro-axonal damage. Modification of cell surface receptors with branched N-glycans coordinates cell growth and differentiation by controlling glycoprotein clustering, signaling, and endocytosis. GlcNAc is a rate-limiting metabolite for N-glycan branching. Here we report that GlcNAc and N-glycan branching trigger oligodendrogenesis from precursor cells by inhibiting platelet-derived growth factor receptor-α cell endocytosis. Supplying oral GlcNAc to lactating mice drives primary myelination in newborn pups via secretion in breast milk, whereas genetically blocking N-glycan branching markedly inhibits primary myelination. In adult mice with toxin (cuprizone)-induced demyelination, oral GlcNAc prevents neuro-axonal damage by driving myelin repair. In MS patients, endogenous serum GlcNAc levels inversely correlated with imaging measures of demyelination and microstructural damage. Our data identify N-glycan branching and GlcNAc as critical regulators of primary myelination and myelin repair and suggest that oral GlcNAc may be neuroprotective in demyelinating diseases like MS.

https://www.sciencedirect.com/science/article/pii/S0021925817506304

So I know that Schwan cells produce myelin sheaths for the PNS while oligodendrocytes form myelin sheaths for the CNS. What I am not understanding is how they wrap around the axon? I know that in the PNS schwann cells form a myelin sheath for a single neuron while oligodendrocytes don't. What does this actually mean? I am having a hard time visualizing it.

Hello! I’m taking a neuro class this semester and I have a lot of questions. My dad has MS so I like to learn as much as I can. My neuro teacher brought up that the CNS has a harder time making new myelin than the PNS, partially due to oligodendrocytes producing myelin slower than Schwann cells do in the PNS. I’m probably explaining this terribly as I’m a beginner but I’d love some clarification on why these cells produce at different rates.

apparently researchers are learning more about how remyelination works, which hopefully will lead to some great meds.

source

Signaling Protein Seen to Help Promote Myelin-making Cells

by Marisa Wexler MS | July 28, 2021

A signaling protein called fractalkine helps to regulate the development of oligodendrocytes, cells of the nervous system responsible for making myelin — the protecting coating of nerve cell fibers that is damaged and lost in multiple sclerosis (MS).

This finding was in the study “Fractalkine signaling regulates oligodendroglial cell genesis from SVZ precursor cells,” published in Stem Cell Reports.

Myelin is a fatty substance that surrounds neurons (nerve cells) like a sheath, helping them to efficiently send electrical signals. In MS, the immune system erroneously attacks the myelin sheath, damaging and killing neurons.

Neural precursor cells, or NPCs, are a type of stem cell that is able to grow and differentiate into several different types of the cells of the nervous system, including oligodendrocytes — the cells that make myelin. When NPCs differentiate into oligodendrocytes, a process called oligodendrogenesis, they first become an intermediary cell type, called an oligodendrocyte precursor cell (OPC), before growing into a mature oligodendrocyte.

The biological mechanisms governing how NPCs grow into OPCs, and then into oligodendrocytes, are still being worked out. A team led by researchers in Canada conducted a series of experiments in cell models and mice to evaluate the role of fractalkine (FKN), a signaling protein, in oligodendrogenesis.

They first confirmed that both NPCs and OPCs express the receptor for FKN (called CX3CR1), which is in line with prior data.

**Researchers then tested the effect of treating NPCs in vitro (in laboratory settings) with varying amounts of fractalkine. After a few days in culture, they found substantially more oligodendrocytes present in cells treated with FKN. Fractalkine’s use, however, did not affect numbers of other cell types, such as neurons, produced by the NPCs.**

FKN