Figure 5.

IRS4^PVH neurons are necessary for normal feeding and bodyweight. A Cre-dependent adeno-associated virus expresses tetanus toxin A and GFP exclusively in Cre-expressing neurons to inhibit synaptic vesicle exocytosis and GFP visualization of the transduced cells (A). (B) Example hit site of IRS4-iCre mice injected with AAV-Flex-TetTox (PVH^TetTox). Bilateral IRS4^PVH neuronal silencing in IRS4-iCre mice (PVH^TetTox) results in both increased bodyweight (C) and increased bodyweight gain (D) in comparison to IRS4-iCre mice injected with a control AAV (PVH^Flex) or wildtype mice injected with AAV-Flex-TetTox (WT^TetTox, mixed-model analysis followed by Tukey’s post-hoc). (E) PVH^TetTox mice (blue) show increased 7-day food intake at early stages of the study (left) in comparison to WT^TetTox mice (orange; one-way ANOVA followed by Tukey’s post-hoc) whereas later stage food intake shows a trend towards increased feeding (dark blue, one-way ANOVA). (F) PVH^TetTox mice show have increased fat mass percentages (F) at early and late stages of obesity development (one-way ANOVA followed by Tukey’s post-hoc). (G–J) 3-day averages of CLAMS measurements were measured during weeks 2–4 of experiments and compared across groups. While PVH^TetTox mice show a trend towards decreased energy expenditure (I), none of these groups are significantly different from one another (one-way ANOVA. Average values ± SEM are shown, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 compared to WT^TetTox; ^Ƹp < 0.05, ^{Ƹ Ƹ}p < 0.01, ^{Ƹ Ƹ Ƹ}p < 0.001 compared to PVH^Flex; BW/feeding: PVH^TetTox n = 6, PVH^Flex n = 17, WT^TetTox n = 13; body composition: PVH^TetTox early n = 6, PVH^TetTox late n = 5, PVH^Flex early n = 10, PVH^Flex late n = 17, WT^TetTox n = 11; CLAMS: PVH^TetTox n = 6, PVH^Flex n = 8, WT^TetTox n = 13.