Fig 2: Synapse quantification in the brains of 24-month-old Htt+/+ (+/+), HttΔQP/ΔQP (ΔQP/ΔQP), and HttΔN17/ΔN17 (ΔN17/ΔN17) mice. (A, B) Representative images from brain sections immunostained with PSD-95 (green) and Vglut2 (red). (A) Dorsal striatum. Arrowheads indicate co-localized PSD-95 and Vglut2 (yellow), which represent thalamostriatal synapses. Scale bar = 2μm. (B) Primary motor cortex (layers I/II). Arrowheads indicate co-localized PSD-95 and Vglut2, which represent thalamocortical synapses. Scale bar = 2μm. (C) Diagram illustrating the two brain regions imaged in (A, B). (D, E) Quantification of PSD-95/Vglut2 co-localization in the dorsal striatum (D) and primary motor cortex (E). HttΔN17/ΔN17 mice had reduced PSD-95+Vglut2+ synapses in the striatum compared to Htt+/+ controls (Htt+/+: 0.05887±0.00683, HttΔQP/ΔQP: 0.07323±0.01249, HttΔN17/ΔN17: 0.02940±0.00391, p = 0.0013). HttΔN17/ΔN17 mice also exhibited a trend toward reduced PSD-95+Vglut2+ synapses in the primary motor cortex compared to Htt+/+ controls and a significant reduction compared to HttΔQP/ΔQP mice (Htt+/+: 0.01652±0.0034, HttΔQP/ΔQP: 0.02490±0.00676, HttΔN17/ΔN17: 0.008080±0.00219, p = 0.0324) (mean±SEM, n = 23–25 images from 3 mice/genotype, 1-way ANOVA).

Fig 3: Interneuron-specific Dact1 mutant mice (IDact1-KO) have fewer excitatory and inhibitory synapses along cortical interneuron dendrites. A-E Experimental design. A Composite z-stack image of a GFP+ interneuron located in upper layers of the primary somatosensory cortex, selected for synaptic puncta quantification from postnatal day 30 mouse brain sections. B This representative composite z-stack image is composed of 9 optical sections, 0.25 microns apart, encompassing the proximal dendrite. C Example of optical section used to confirm pre- and post-synaptic co-localization along the GFP+ dendrite. D Representative serial z-stack images used to confirm synaptic puncta co-localization in each z-plane. Co-localized puncta visible in adjacent serial sections are scored only once to avoid duplicate counting of individual synapses. E Boxed region is shown at the higher magnification, as employed to identify: VGAT/Gephyrin (inhibitory, F) and Vglut1/PSD95 (excitatory, F') co-localized puncta (arrowheads) along the GFP+ dendrite in control (left) and IDact1-KO (right) mice. Quantification of co-localized inhibitory (G) and excitatory (G') pre- and post-synaptic puncta in control (open bars) and IDact1-KO mutants (closed bars). Data shown are mean ± sem of at least 3 independent experiments, collected from at least 3 mice per genotype, 5-10 neurons per animal. *p<0.05. Scale bars = 5 µm.

Fig 4: Inhibition of caspase- and calpain-dependent neuronal loss after PAL treatment. (a) Caspase-3 inhibition was independent of Bcl family proteins (Bcl-2 and Bax) in APP/PS1 mouse brains after PAL treatment. n = 8. (b) PAL treatment suppressed the expressions of calpain-1 and α-spectrin (145 KD), whereas increased the expression of full-length HSP70. n = 8. (c) PAL treatment increased the co-localization of cathepsin D (green) with LAMP1 (red). Three sections/brain, n = 5. (d) NeuN, SYP and PSD95 upregulation were induced by PAL treatment, n = 8. (e-f) NeuN positive cells in cortex and SYP intensities in cortex and CA1 region were increased after PAL treatment. Three sections/brain, n = 5. *p < .05, **p < .01 (Student's-t-test). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig 5: Synaptosomal densities of AdipoR1 and AdipoR2. (A) Representative immunoblot showing AdipoR1 immunoreactivity normalized to beta actin in hippocampal fractions. (B) Representative immunoblot showing AdipoR2 immunoreactivity normalized to beta actin in hippocampal fractions. Hippocampal lysate was divided into total (Total) and synaptosomal (Syn) fractions. The synaptosome was further fractionated into the PSD (Post) and non-PSD (Pre) fractions. Synaptic fractionation efficiency is represented by immunoreactivity of PSD95 and SNAP25 for Post and Pre, respectively. Twenty five micrograms of protein were loaded per lane. Bars represent mean ± SEM from 3 independent experiments, hippocampi from 2 mice were pooled for each experiment (n = 6 mice); *indicates significant difference vs. Total; #indicates significant difference vs. Post; *p < 0.05, **p < 0.01, ###p < 0.001. Tukey's post hoc test was used for multiple comparisons.