Multiple Early-Life Seizures Alters Neonatal Communicative Behavior in Fmr1 Knockout Mice.

Fragile X syndrome (FXS) is the leading monogenic cause of intellectual disability and a significant contributor to Autism Spectrum Disorder. Individuals with FXS are subject to developing numerous comorbidities, one of the most prevalent being seizures. In the present study, we investigated how seizures affected neonatal communicative behavior in the FXS mouse model. On postnatal day (PD) 7 through 11, we administered 3 flurothyl seizures per day to both Fmr1 knockout and wild-type C57BL/6J male mice. Ultrasonic vocalizations were recorded on PD12. Statistically significant alterations were found in both spectral and temporal measurements across seizure groups. We found that induction of seizures across PD7-11 resulted in an increased fundamental frequency (pitch) of ultrasonic vocalizations produced (p < 0.05), a longer duration of calls (p < 0.05), and a greater cumulative duration of calls (p < 0.05) in both genotypes. Induction of seizures across PD7-11 also resulted in a decreased latency to the first emitted vocalization (p < 0.05) and a decrease in mean power (loudness) for their vocalizations (p < 0.05). Early-life seizures also resulted in an increase in the number of downward and frequency step call types (p < 0.05). There was a significant increase in the number of chevron calls emitted from the Fmr1 knockout mice that received seizures compared to knockout control and wild-type seizure mice (p < 0.05). Overall, this study provides evidence that early-life seizures result in communication impairments and that superimposing seizures in Fmr1 knockout mice does produce an additional deficit in vocalization.

Rapamycin improves social and stereotypic behavior abnormalities induced by pre-mitotic neuronal subset specific Pten deletion.

The mechanistic target of rapamycin (mTOR) pathway is a signaling system integral to neural growth and migration. In both patients and rodent models, mutations to the phosphatase and tensin homolog gene (PTEN) on chromosome 10 results in hyperactivation of the mTOR pathway, as well as seizures, intellectual disabilities and autistic behaviors. Rapamycin, an inhibitor of mTOR, can reverse the epileptic phenotype of neural subset specific Pten knockout (NS-Pten KO) mice, but its impact on behavior is not known. To determine the behavioral effects of rapamycin, male and female NS-Pten KO and wildtype (WT) mice were assigned as controls or administered 10 mg/kg of rapamycin for 2 weeks followed by behavioral testing. Rapamycin improved social behavior in both genotypes and stereotypic behaviors in NS-Pten KO mice. Rapamycin treatment resulted in a reduction of several measures of activity in the open field test in both genotypes. Rapamycin did not reverse the reduced anxiety behavior in KO mice. These data show the potential clinical use of mTOR inhibitors by showing its administration can reduce the production of autistic-like behaviors in NS-Pten KO mice.