Fig. 5

GEE activates IGF1R-CaMKIV/ERK signaling and thus promotes histone acetylation and BDNF expression. (a,b) In 3XTg AD mice, GEE activates IGF1R with upregulation of CaMKIV/ERK/HAT/BDNF signaling in their offspring (7 m old), while simultaneous inhibition of IGF1R by BMS abolishes GEE-induced histone acetylation, CaMKIV and ERK activation, and BDNF expression (n = 3, one–way ANOVA, *P < 0.05, **P < 0.01, ***P < 0.001 vs. Ctrl; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. GEE). (c,d) In 3-m-old wildtype mice, brain lateral ventricle infusion of IGF1 activates IGF1R with an upregulation of CaMKIV/ERK/HAT/BDNF signaling, while simultaneous inhibition of IGF1R by BMS attenuates these effects (n = 3, one–way ANOVA, *P < 0.05, **P < 0.01,***P < 0.001 vs. Ctrl; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. IGF1). (e, f) In HEK293 cells, upregulation of IGF1R by IGF1 treatment activates CaMKIV and ERK with increased histone acetylation, while inhibition of IGF1R by PPP or BMS attenuates these effects (n = 6, one–way ANOVA, *P < 0.05, **P < 0.01, ***P < 0.001 vs. Ctrl; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. IGF1; & P < 0.05, &&P < 0.01, &&&P < 0.001 vs. IGF1 + PPP). (g, h) In HEK293 cells, simultaneous inhibition of ERK or CaMKIV by CDC0994 or by expressing the inactive CaMKIVK75E abolishes IGF1-induced histone acetylation (n = 3, one–way ANOVA, *P < 0.05, **P < 0.01, ***P < 0.001 vs. Ctrl; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 vs. IGF1; & P < 0.05, &&P < 0.01, &&&P < 0.001 vs. IGF1 + CDC0994). (i) GEE increases the plasma level of IGF1 in the pregnant host, as measured by ELISA (n = 8, unpaired t-test, **P < 0.01 vs. Ctrl). (j) GEE increases the IGF1R level in E19 embryo brain, as measured by dot blotting (n = 5, unpaired t-test, ***P < 0.001 vs. Ctrl). Data are presented as the mean ± s.e.m. and offspring tissue collected from at least 3 independent litters of mice