Fig. 1: Systemic PF4 enhances adult hippocampal neurogenesis in vivo.

a Experimental design of PF4 injection paradigm in young mice. b, c Intravenous (i.v.) PF4 injections for 1 week did not affect neural precursor cell proliferation in the subgranular zone (SGZ; n = 10 mice in saline group; n = 9 mice in PF4 group; counts of one hemisphere), but increased the number of doublecortin⁺ (DCX⁺) cells (n = 15 mice per group; counts of one hemisphere). d Experimental design of the double-labelling paradigm with CldU and IdU. e Acute administration of PF4 did not affect neural precursor cell proliferation, including the recruitment of cells from quiescence (n = 20 mice per group). f Running paradigm of PF4 knockout (KO) mice. g Representative images of Ki67⁺ cells in the SGZ of PF4 KO and wildtype (WT) mice. Scale bar: 50 μm. h PF4 KO mice show a significant reduction in the number of proliferating cells compared to wildtype mice. Physical exercise did not increase neural precursor proliferation in PF4 KO mice (WT STD n = 12; WT RUN n = 8; KO STD n = 14; KO RUN n = 8; counts of one hemisphere). i Representative images of DCX⁺ cells in the dentate gyrus (DG) of PF4 KO and wildtype mice. Scale bar: 50 μm. j PF4 KO mice have significantly lower levels of baseline neurogenesis compared to wildtype littermates (WT STD n = 12; KO STD n = 14; counts of one hemisphere). STD standard-housing, RUN 10-day running. Bars are mean ± SEM. Statistical analysis was performed using unpaired Student’s two-tailed t tests in (c) and (j), and one-way ANOVA with Sidak comparison in (h). *p < 0.05, **p < 0.01, ***p < 0.001. Source data are provided as Source Data file.