So surprised! Scientists found that glial progenitor cells actually directly engulfed synapses and reshaped neural circuits

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Microglia and astrocytes encroach on excess synapses during the first week after birth, promoting synaptic fineness
in the mammalian visual system.
Oligodendrocyte precursor cells (OPCs) are glial progenitor cells that produce myelinated oligodendroglia
.
OPC was originally born in the subventricular region of the embryonic neural tube, where it continues to proliferate and differentiate into oligodendrocytes
.

Although the rate of oligodendrocyte production drops dramatically as the brain matures, OPC remains abundant and maintains its ability to
differentiate in the adult brain.
On September 28, 2022, Lucas Cheadle's research team at Cold Spring Harbor Laboratory in the United States found in the form of Brief Communication in the journal Nature Neuroscience that oligodendrocyte precursor cells not only have the function of forming oligodendrocytes, but also have the function of
synaptic pruning.

The period of significant empirical-dependent synaptic refinement experienced by thalamic-cortical (TC) input from dorsal knee body (dLGN) in the third week of birth is a classic model
for studying synaptic pruning.
The researchers engulfed TC input synapses in adolescent and adult oligodendrocyte precursor cells and phagocytosis more synapses than microglia, while mature oligodendrocytes did not enphagoguate synapses, suggesting that oligodendrocyte precursor cells have stronger
synaptic pruning than microglia.

Figure 1: Oligodendrocyte progenitor cells phagocytic synaptic structure

The vast majority of OPCs (88.
5%) were found to enphagoguate synapses after specifically labeling oligodendrocyte precursor cells by the NG2-cre tool mice, with approximately 16.
5 synaptic inputs
per OPCs.
High-throughput flow cytometry analyzed 25,094 OPCs and found synaptic components in 80% of OPCs, which strongly confirmed the phagocytic synaptic input
of OPCs.

Similar to the mechanism of phagocytic synapses in microglia, a large number of OPCs express the phagocyte receptor LRP1, and synaptic input within OPCs cells is co-localized with early phagosomes (EEA1), late phagosomes (Rab7), and phagolysosomes (Lamp2) markers, and these data indicate that OPC digests synapses
at least in part by phagocytosis.

Figure 2: Visual information deprivation affects oligodendrocyte progenitor cells phagocytic synaptic structure

3-week-old young mice are placed in a dark environment for one week, followed by exposure to a daylight environment to receive light information input
.
This stimulation does not cause microglia phagocytosis, but promotes OPCs phagocytosis
.

Studies have shown that microglia promote the proliferation and differentiation of OPC
.
After clearing microglia by chemical inhibitors in the third week after birth, OPCs phagocytosis synapses
can be significantly reduced.
These mice that clear microglia can significantly promote OPCs phagocytosis synapses after receiving visual information deprivation
.

This paper discovers a novel way that oligodendroglial precursor cells interact with neurons: developmental oligodendroglial precursor cells reshape neural circuits
by phagocytosis.

【References】

1.
https://doi.
org/10.
1038/s41593-022-01170-x

The images in the article are from references