Fig. 5.

Aging impedes poststroke oligodendrogenesis and alters the pattern of oligodendrocyte recovery. (A) (Left) UMAP visualization of oligodendrocyte lineage cells including 1,289 OLs and 101 OPCs from all aged groups and with individual visualizations split by groups. (B) Bar plots showing the proportions of the major subsets (accounting for >10% in all groups) in each group. (B) UMAP visualizations of OPCs in young and aged groups over time, colored by the cell cycle stages inferred by CellCycleScoring R function. (C) Representative images (Left) of PDGFRα and Ki67 immunofluorescence staining on brain sections of young and aged mice at 3 d after MCAO. Quantification (Right) of the numbers PDGFRα⁺ Ki67⁺ cells in the peri-infarct areas. n = 6. *P < 0.05, two-tailed, unpaired t test. Arrowheads, PDGFRα⁺Ki67⁺ cells. (Scale bar, 100 μm.) (D) Representative images (Left) of APC and BrdU immunofluorescence staining on brain sections of young and aged mice at 14 d after MCAO. Dashed lines show the position of the external capsule. Quantification (Right) of the numbers of APC⁺ BrdU⁺ cells in the ipsilateral infarct areas and parallel areas on the contralateral side. n = 5 to 6. *P < 0.05, two-tailed, unpaired t test. (Scale bar, 50 μm.) (E) The distribution of OLs on pseudotemporal axes in the indicated aged groups. Arrowheads, peak of pseudotemporal distribution density. Asterisks, age-specific peaks. Gray dashed lines, the density curves of young groups. Color-coded bars indicated the positions of OLs on pseudotemporal axes. (F) Line charts (Left) showing eight clusters of genes with distinct temporal kinetics in aged groups and the numbers of included genes. Heatmap (Middle) showing the expression level of top 10 genes in each pattern. Representative predicted functions and genes involved in each cluster are annotated on the right.