Alzheimer-associated Aβ oligomers impact the central nervous system to induce peripheral metabolic deregulation. (2015)
Figure 7

AβO-induced peripheral glucose intolerance and hypothalamic insulin resistance are mediated by TNF-α signaling and hypothalamic ER stress

Glucose tolerance test (2 g glucose/kg body weight, i.p.) in mice that received i.c.v. injections of vehicle, vehicle + TUDCA, AβOs or AβOs + TUDCA (when used, TUDCA was administered in 5 i.c.v. injections of 5 μg TUDCA each, before and after oligomer injection; see Materials and Methods. Control groups received injections of saline). Glucose tolerance test (GTT) was performed 7 days after i.c.v. injection of vehicle or AβOs. Bar graph represents areas under the curves (AUC) in the time course plots (n = 15 Veh; 15 AβOs; 10 Veh + TUDCA; 16 AβOs + TUDCA). Data are representative of two independent experiments with similar results. Left panel: **P = 0.0048, **P = 0.003, two-way ANOVA followed by Bonferroni post hoc test; right panel: *P = 0.0384, one-way ANOVA followed by Bonferroni post hoc test.

Plasma noradrenaline (NA) levels measured 7 days after i.c.v. injection of vehicle, vehicle + TUDCA, AβOs or AβOs + TUDCA in mice (n = 7 animals/group). Data are representative of two independent experiments with similar results. *P = 0.0071, one-way ANOVA followed by Bonferroni post hoc test.

Glucose tolerance test (2 g glucose/kg body weight, i.p.) in TNFR1−/− mice or wild-type littermates performed 7 days after i.c.v. injection of vehicle or AβOs. Bar graph represents areas under the curves (AUC) in the time course plots (n = 8 WT + Veh; 7 WT + AβOs; 7 TNFR−/− + Veh; 8 TNFR−/− + AβOs). Left panel: **P = 0.0049, ***P < 0.0001, two-way ANOVA followed by Bonferroni post hoc test; right panel: *P = 0.0001, one-way ANOVA followed by Bonferroni post hoc test.

Western blot analysis of phospho-IKKβ (D; n = 6 WT + Veh; 6 WT + AβOs; 4 TNFR−/− + Veh; 6 TNFR−/− + AβOs) and IRS-1pSer636 levels (E; n = 6 WT + Veh; 5 WT + AβOs; 6 TNFR−/− + Veh; 5 TNFR−/− + AβOs) in the hypothalamus of wild-type (WT) or TNFR1−/− mice 10 days after i.c.v. injection of vehicle or AβOs. Representative images from Western blot experiments were always run on the same gels but represent noncontiguous lanes. In (D), *P = 0.0088, Student's t-test; in (E), *P = 0.0428, one-way ANOVA followed by Bonferroni post hoc test.

Adult Swiss mice pre-treated with minocycline or PBS received a single i.c.v. injection of vehicle or 10 pmol AβOs, and hypothalamic levels of mRNA for AgRP (F; n = 5 Veh; 6 AβOs; 5 Veh + Mino; 4 AβOs + Mino) and NPY (G; n = 14 Veh; 13 AβOs; 8 Veh + Mino; 9 AβOs + Mino) were analyzed 7 days after injection. In (F), *P = 0.0097, one-way ANOVA followed by Bonferroni post hoc test; in (G), *P = 0.0219, one-way ANOVA followed by Bonferroni post hoc test.

Glucose tolerance test (GTT) in APP/PS1 mice before and after i.c.v. injection of infliximab (0.2 μg daily for 4 days). Bar graph represents areas under the curves (AUC) in the time course plots (n = 9 animals/group). Left panel: *P = 0.0177, two-way ANOVA followed by Bonferroni post hoc test; right panel: *P = 0.0327, paired t-test.

Data information: Data are expressed as means ± SEM. To assess statistical significance, AβO-injected mice were compared to vehicle-injected mice.

Source data are available online for this figure.