Fig. 6.

Glutamate alters cholesterol biosynthesis in mature oligodendrocytes (OLs) and impairs myelination. (A and B) scRNAseq of human OLs in primary culture exposed to glutamate 1 mM or vehicle (control) for 12 h (n = 2 different donors/batch). (A) UMAP (uniform manifold approximation and projection) showing the results of SNN clustering and bar chart illustrating the proportion of each cluster across the different conditions (glutamate versus control). (B) Heatmap of top DEGs in mature OLs exposed to glutamate compared to control condition (adjusted P value < 0.01, absolute LFC ≥ 0.3), relative expression scaled by gene across subpopulations and conditions (row). (C and D) Impact of glutamate on human OLs ensheathing ability on nanofibers. (C) Representative confocal microscopy images (Scale bar, 30 µm.) and (D) quantitative analysis of ensheathing OLs (each dot represents the percentage of OLs ensheathing nanofibers in one well, n = 3 preparations, in duplicates. (E) Impact of exposure to glutamate (1 mM) on myelinated area in organotypic hippocampal slices by immunofluorescence (n = 40 reslices treated with glutamate, n = 35 reslices for control). Statistical analysis for D was performed using one-way ANOVA with Tukey’s post hoc test and for E using two-sided paired Student’s t test. *P < 0.05; **P < 0.01; ***P < 0.001.