Fig 2: CPZ/Rap treatments impede NSC proliferation and differentiation(A and B) Schematic diagram and the timeline of the experiments to assay NSC proliferation and differentiation in 6-week-old wild-type mice receiving the Chow/Rap or CPZ/Rap treatment.(C) Images and quantification of MBP, PLP, CC1, and Ng2 in the DG of Chow/Rap and CPZ/Rap mice. n = 5. Scale bars, 50 μm.(D) Representative images and quantification of total proliferating cells (EdU+) in the DG of the indicated groups. n = 5 animals per group. Scale bar, 100 μm.(E) Representative images and quantification of EdU+GFAP+Sox2+ triple-labelling radial glia-like (RGL) NSCs cells and transiently amplifying progenitor (TAP) EdU+GFAP-Sox2+ cells in the DG of the indicated groups. n = 5 animals per group. Scale bar, 50 μm.(F) Representative images and quantification of BrdU+ cells and BrdU+ DCX+ immature neurons in the DG of the indicated group. n = 5 animals per group. Scale bars, 50 μm.(G) Representative images and quantification of BrdU+ cells and BrdU+ NeuN+ mature newborn neurons in the DG of the indicated groups. n = 5 animals per group. Scale bars, 50 μm. All data were presented as the mean ± SEM. Statistical significance was evaluated with Student’s t-test. Nonsignificant comparisons were not identified. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001.

Fig 3: Environmental enrichment increases spatial information encoding in the DG but this effect is blocked in mice with ablated adult neurogenesis.a Experimental timeline, including irradiation, surgery, housing environment, and in vivo imaging. b Example of calcium imaging field of view. Cells that were active during a recording are shaded in color. c Immunofluorescence labelling of DCX positive neurons in the DG of non-irradiated (top) and irradiated (bottom) mice. Arrows denote neurogenic subgranular layer in the upper and lower leaves of the DG where DCX-expressing cells can be found. d Number of DCX-expressing neurons in imaged mice from regular cage (RC), enriched environment (EE) groups and corresponding irradiated groups (Irr+RC, Irr+EE). (nRC = 4 mice, nIrr+RC = 4 mice, nEE = 4 mice, nIrr+EE = 3 mice, average of three 40 µm slices per mouse, Welch ANOVA test with Dunnett’s T3 multiple comparisons, RC vs Irr+RC **p = 0.008, RC vs EE **p = 0.009, Irr+RC vs Irr+EE ns p > 0.999, EE vs Irr+EE **p = 0.004). e Example calcium traces (top) and respective position of animal on the treadmill (bottom). f Accuracy in decoding position of mouse on treadmill from calcium traces (RC vs Irr+RC: *p = 0.006, EE vs Irr+EE: ****p = 2.15 × 10−5, **RC vs EE: p = 0.03, ANOVA, Holm-Sidak correction for multiple comparisons, n = 4 mice, 42 neurons subsampled per mouse. Dotted line is chance performance level (5%). Error bars represent +/- SEM in all plots. All scale bars = 50 µm.

Fig 4: Meth impairs NSCs proliferation and differentiation, decreased OB neurogenesis. (A) Representative images of the EdU+ cell rate of NSCs. Scale bar, 50 μm. (B) Statistical analysis of the proportion of EdU+ cells among the total cell population (n = 4). (C) Representative images of newly differentiated neurons and astrocytes from cultured NSCs. Scale bar, 50 μm. (D) Statistical analysis of the proportion of Tuj1+ or GFAP+ cells among the total cell population (n = 4). (E) Expression levels of neurons and astrocytes in cultured NSCs were examined by WB. (F,G) Quantification of protein levels shown in E. β-actin served as a normalization control (n = 4). (H) Diagram of the BrdU administration schedule in mice. The BrdU administration dosages were 100 mg/kg (upper panel) and 50 mg/kg (lower panel). Red arrow indicates experiments for detecting NSCs proliferation, while green arrow indicates experiments for assessing the fate determination and long-term fate of NSCs. (I) Schematic diagram of the detected SVZ region. (J) Representative images of proliferating NSCs in SVZ in vivo. Scale bar, 20 μm. (K) Statistical analysis of the number of BrdU+ Sox2+ cells. (L)Representative images of NSCs and mature astrocytes. Scale bar, 20 μm. (M). Statistical analysis of the number of Nestin+ cells (n = 4). (N) Statistical analysis of the number of Nestin− GFAP+ cells (n = 4). (O) Representative images of newborn immature neurons and newborn astrocytes derived from NSCs. Scale bar, 20 μm or 10 μm (insets). (P) Statistical analysis of the proportion of BrdU+ GFAP+ cells among the total cell population in SVZ (n = 4). (Q) Statistical analysis of the proportion of BrdU+ DCX+ cells among the total cell population in SVZ (n = 4). (R) Neuroblasts derived from SVZ NSCs migrate along the RMS to the OB, where they mature and replace interneurons in the GCL or the GL. (S) Representative images of newly generated mature neurons in the OB. Scale bar, 50 μm. (T) Statistical analysis of the number of BrdU+ NeuN+ cells (n = 4). CPu, caudate putamen (striatum); CC, corpus callosum; LV, lateral ventricle; RMS, rostral migratory stream; GCL, granule cell layer; GL, glomerular layer. Data are presented as mean ± SEM. (B), (F), (G), (K), (M), (N), (P), (Q) and (T) by Student's t-test; (D) by one-way ANOVA followed by post hoc comparison using Dunnett’s test. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001

Fig 5: Overexpression of Stx17 can rescue impaired neurogenesis and restore olfactory function in mice. (A) Schematic representation of rAAV-Nestin-Stx17-mCherry injection in the infected SVZ. Scale bar, 20 μm. (B) Expression levels of Notch1 pathway and Stx17 proteins in the SVZ after rAAV injection were examined by WB. (C) Quantification of protein levels shown in B. β-actin served as a normalization control (n = 4). (D) Representative images of proliferating NSCs in SVZ in vivo after overexpression of Stx17. Scale bar, 20 μm. (E) Representative images of NSCs and mature astrocytes after overexpression of Stx17. Scale bar, 20 μm. (F) Statistical analysis of the number of BrdU+ Sox2+ cells (n = 4). (G) Statistical analysis of the number of Nestin+ cells (n = 4). (H) Statistical analysis of the number of Nestin− GFAP+ cells (n = 4). (I) Representative images of newborn immature neurons and newborn astrocytes derived from NSCs after overexpression of Stx17. Scale bar, 20 μm or 10 μm (insets). (J) Statistical analysis of the proportion of BrdU+ DCX+ cells or BrdU+ GFAP+ cells among the total cell population in SVZ (n = 4). (K) Representative images of newly generated mature neurons in the OB after overexpression of Stx17. Scale bar, 50 μm. Statistical analysis of the number of BrdU+ NeuN+ cells (n = 4). (L-P) Overexpression of Stx17 restored olfactory sensitivity, olfactory discrimination, olfactory discrimination, olfaction-dependent food exploration ability in mice (n = 8). Scale, 18 cm. F, familiar; N, novel; ns, not significant. Data are presented as mean ± SEM. (C), (F), (G), (H), (J) and (K) by one-way ANOVA followed by post hoc comparison using Dunnett’s test; (L-O) by two-way RM ANOVA with Bonferroni’s multiple comparisons test; (P) by Student's t-test. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001