Fig. 5: Different patterns of maternal separation trigger different outcomes in stress susceptibility via IGF-1-mediated C/EBPβ activity.

a Schematic representation of the upstream signaling pathway of early life experience affecting C/EBPβ/DRP1 axis, contributing to adolescent depression. b Schematic representation of the experimental procedure for maternal separation on different durations, and AcSD paradigm. c Measurement of C/EBPβ activity in the mPFC neurons of WT mice exposed to different maternal separations and AcSD. d Measurement of Cebpb mRNA levels in the mPFC neurons of WT mice exposed to different maternal separations and AcSD. Data in (c, d) are presented as the mean ± SEM (n = 4 for each group; one-way ANOVA and Bonferroni’s multiple comparison test). e, f. Representative immunoblots and quantification of LAP/LIP ratio in the mPFC neurons of WT mice from (b). Data are representative of three independent experiments. Data are presented the mean ± SEM (n = 4 for each group; one-way ANOVA and Bonferroni’s multiple comparison test). g Schematic representation of molecular pathway hypothesis that IGF-1 induces inhibition of neuronal C/EBPβ activity. h Measurement of the IGF-1 levels in the blood, the mPFC and the hippocampus of WT mice from (b). Data are presented the mean ± SEM (n = 6 for each group; one-way ANOVA and Bonferroni’s multiple comparison test). i Representative immunoblots of LAP/LIP ratio, p-IGF-1R/IGF-1R, p-Akt/Akt and p-S6K1/S6K1 in the primary mouse cortex neurons with vehicle or IGF-1. Data are representative of three independent experiments. j Schematic representation of the experimental procedure for maternal separation for 10 min × 2, and AcSD paradigm and behavioral tests with the mPFC infusion of anti-IgG or anti-IGF-1. k Representative immunoblots of LAP/LIP ratio and DRP1 expressions in the mPFC neurons of WT mice exposed to maternal separation for 10 min × 2, and AcSD paradigm with the mPFC infusion of anti-IgG or anti-IGF-1. Data are representative of three independent experiments. l, m Behavioral tests of WT mice exposed to maternal separation for 10 min × 2, and AcSD paradigm with the mPFC infusion of anti-IgG or anti-IGF-1. Measurement of social interaction ratio, time in interaction zone with target (l), and the percentage of sucrose preference (m) in WT mice with indicative treatments. Data in (l, m) are presented as the mean ± SEM (n = 8 mice for anti-IgG group, n = 10 mice for anti-IGF-1 group; unpaired t-test with Welch’s correction). n Schematic representation of the experimental procedure for AcSD paradigm and behavioral tests with the mPFC infusion of vehicle or IGF-1. o Representative immunoblots and quantification of LAP/LIP ratio, and p-DRP1 and DRP1 expressions in the mPFC neurons of WT susceptible mice exposed to AcSD paradigm with the mPFC infusion of vehicle or IGF-1. Data are representative of three independent experiments. Data in (o) are presented as the mean ± SEM (n = 6 for each group; two-sided unpaired t-test with Welch’s correction). p Scatter plot depicting the distribution of social interaction ratio for susceptible (ratio < 1), and resilient (ratio ≥ 1) after the AcSD paradigm. The red, and blue dots represent the susceptible, and resilient groups, respectively. Data in (p) are presented as the mean ± SEM (n = 22 for susceptible group; n = 26 for resilient group; two-sided unpaired t-test with Welch’s correction). q, r Behavioral tests of WT susceptible mice exposed to AcSD paradigm with the mPFC infusion of vehicle or IGF-1. Measurement of social interaction ratio, time in interaction zone with target (q), and the percentage of sucrose preference (r) in WT susceptible mice with indicative treatments. Data in (q, r) are presented as the mean ± SEM (n = 9 mice for each group; two-sided unpaired t-test with Welch’s correction). See also Supplementary Figs. 8–10. Source data are provided as a Source Data file.