Extended Data Fig. 3: Both neurogenic activity and distinct molecular profile between astrocytes and qNSCs are largely preserved with advancing age.
a-d, Representative images of neurogenic lineages in SGZ of (upper) young, (middle) middle-age and (lower) old mice showing decreased neurogenesis with aging. (a) Radial NSCs were labeled by GFAP and SOX2 with radial morphology in SGZ. Note that GFAP and SOX2 are detected simulataneously (SOX2: nucleus; GFAP: radial process) in the same channel to facilitate identification of radial glia-like progenitors, as used by others before23. (b) aNSPCs were labeled by Ki67 including (c) radial and non-radial proliferating progenitors. Radial and non-radial aNSPCs were distinguished by the existence of the radially oriented GFAP-process (pointed out by arrowhead). (d) NB/IMNs were labeled by DCX. e-g, Quantification of (e) radial NSCs (young: 11151 ± 375 cells; middle-age: 3923 ± 200 cells; old: 1324 ± 154 cells; two-tailed unpaired t-test with Welch’s correction, ****P < 0.0001 between young and middle-age, ****P < 0.0001 between middle-age and old, ****P < 0.0001 between young and old), (f) aNSPC (young: 1902 ± 73 cells; middle-age: 433 ± 22 cells; old: 74 ± 17 cells; two-tailed unpaired t-test with Welch’s correction, ****P < 0.0001 between young and middle-age, ****P < 0.0001 between middle-age and old, ****P < 0.0001 between young and old), and (g) NB/IMN (young: 12131 ± 392 cells; middle-age: 1079 ± 32 cells; old: 173 ± 25 cells; two-tailed unpaired t-test with Welch’s correction, ****P < 0.0001 between young and middle-age, ****P < 0.0001 between middle-age and old, ****P < 0.0001 between young and old) in SGZ of mice in different ages. h, Spatial feature plots of Igfbpl1 showing age-dependent decrease in DG. Color gradient indicates the log-normalized gene expression level. i, Feature plots of selected TFs and their GRNs showing good agreement between individual gene expression and their GRN activity. Color gradient indicates the (upper) log-normalized gene expression level and (lower) GRN activity score. j, Projection of pseudotime value in the UMAP space. k, Gene expression dynamics along pseudotemporal trajectory of selective genes representing qNSC (Rfx4 and Sox9), aNSPC (Ascl1 and Hmgb3) and NB/IMN (Neurod1 and Neurod2). Shading indicates 95% confidence interval. l, UMAP plot of astrocytes and qNSCs showing distinct molecular profiles. m, Volcano plot showing DEGs between astrocytes and qNSCs. For all dots shown in color by an adjusted P < 0.05 with Bonferroni correction, MAST differential test. n, Feature plots of selected genes showing (left) shared, (middle) astrocyte-specific and (right) qNSC-specific genes. Color gradient indicates the log-normalized gene expression level. o, Immunofluorescent staining showing the majority of radial NSCs (GFAP+SOX2+) labeled by Gli1-tdTOM in the SGZ across all three ages do not overlap with astrocytic marker, S100b (n = 3 mice for each condition). DEG, differentially expressed gene, GFP, green fluorescent protein, GRN, gene regulatory network, MO, month-old, qNSC, quiescent neural stem cell, Sac, sacrifice, TOM, tomato, UMAP, uniform manifold approximation and projection, Scale bars, (a) 100 μm, (b-d and o) 20 μm and (h) 200 μm.
