We have previously shown essentially no significant NAP effects on behavior in the Adnp+/+ mice
Further results showed no significant brain penetration of Evans blue ( < 0.1 ng/ml, which was the limit of detection), and no difference between chlorobutanol and saline.
Representative pictures show penetration of the Evans blue dye in the periphery (Fig. 1d), but not in the brain (Fig. 1e), with brain concentration values < 0.03 ng/ml (Supplemental Fig. S1)
Figure 1a shows enhanced brain/body bioavailability in the presence of the newly tested vehicle, chlorobutanol over time.
Fig. 1b displays enhanced brain bioavailability by picture evaluation. Fig. 1c shows quantitative assessment of three independent experiments, revealing the dramatic 4-fold increase in specific brain bioavailability.
These findings provide clear evidence that the blood brain barrier remained intact in the presence of chlorobutanol
We have also extended the experiments to female mice, and interestingly, in the social recognition test CB- or NAP-treated females displayed significant preference to mice rather than objects (Supplemental Fig. S2C), unlike previous findings with the “DD” formulation.
As social behavior depends on olfaction, this was also measured showing intact odor discrimination ability in CB-treated males (Fig. 2e) and a sex difference, with no preference for a specific olfactory cue in CB-treated females (Supplemental Fig. S2E), thus corroborating previous findings observed for DD-treated mice
Our original cell culture results showed NAP protection against excitotoxicity over a broad concentration range, suggesting an involvement of the glutamatergic system in ADNP/NAP activity
Furthermore, in both sexes, Adnp haploinsufficiency showed significantly inhibited social memory, which was completely ameliorated by NAP treatment (Fig. 2d, males and Supplemental Fig. S2D, females).
Given the fact that children carrying ADNP mutations (ADNP syndrome children) exhibit motor impairments, we also utilized the hanging wire test to measure potential impairments and amelioration by NAP. Results showed a significant impairment due to Adnp haploinsufficiency and amelioration by NAP treatment (Fig. 2f)
In females, hippocampal VGLUT1 was not affected by the Adnp genotype or NAP treatment (Supplemental Fig. S4A)
In the cerebral cortex, female Adnp+/− mice exhibited significantly reduced VGLUT1 expression, with no effect for NAP (Supplemental Fig. S4B).
When using area counting, NAP treatment was shown to provide full protection against VGLUT1 decreases in both the hippocampus and the cerebral cortex (Fig. 4f, h), whereas in terms of intensity changes in VGLUT1 expression, NAP effect was significant in the hippocampus (Fig. 4g), and exhibited a trend of improvement in the cortex (Fig. 4i).
In males, complementing DTI data (Fig. 3) our results (Fig. 4a) revealed that in Adnp+/− mice, Slc17a7 (VGLUT1) gene expression was significantly decreased in the hippocampus, and completely reversed by NAP treatment (Fig. 4a), while in the cerebral cortex, NAP treatment resulted in a small, albeit significant decrease in the VGLUT1 transcript (Fig. 4b).
In this respect, our previous data associated postsynaptic density protein 95 (PSD95, also known as DLG4) with ADNP/NAP activity
Adnp+/− mice compared with Adnp+/+ mice spent significantly shorter time periods in exploring the new objects, indicative of impaired memory, with intranasal NAP-CB treatment completely ameliorating this impairment (Fig. 2a, b).
While no effect was observed in the Adnp+/− male mouse social recognition, with preference to mice rather than objects (Fig. 2c), Adnp haploinsufficiency showed significantly inhibited social memory, which was completely ameliorated by NAP-CB treatment (Fig. 2d).
Furthermore, FA which is used to characterize the organization of white matter fibers, was shown to be significantly increased in Adnp+/− mice, thus implying of structural impairment. Importantly, this DTI observed structural impairment was ameliorated by NA-PCB treatment (Fig. 3b).
Interestingly, in CB-treated males, Adnp haploinsufficiency showed a reduction in the total time spent with the different odors, which was significantly increased upon NAP treatment (Fig. 2e, inset).
As opposed to this, in females, CB-treated Adnp haploinsufficient mice showed significant increased total odor sniffing time, which was significantly reduced by NAP treatment (Supplemental Fig. S2E, inset).
Here, Adnp haploinsufficiency in male mice has led to a significant increased MD in the hippocampus (Fig. 3a).
At the protein level, a significant reduction in VGLUT1 was observed in both the hippocampus (Fig. 4c–e, immunohistochemistry, 4FG, densitometry) and cerebral cortex (Fig. 4h, i, densitometry).
Also, as our previous experiments, labeling dendritic spines in vivo, showed reduction in spine density in the hippocampus and the cortex as a consequence of Adnp deficiency and protection by NAP injection, we now sought to determine possible genotype/treatment/sex effects on the vesicular glutamate transporter VGLUT1
VGLUT1 is both necessary and sufficient for uptake and storage of glutamate, and thus comprises the sole determinant for an excitatory glutamatergic phenotype
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If you find BEL Commons useful in your work, please consider citing: Hoyt, C. T., Domingo-Fernández, D., & Hofmann-Apitius, M. (2018). BEL Commons: an environment for exploration and analysis of networks encoded in Biological Expression Language. Database, 2018(3), 1–11.