S-Adenosyl-Methionine alleviates sociability aversion and reduces changes in gene expression in a mouse model of social hierarchy.

Epigenetic changes are an important pathogenic mechanism in many diseases, including a variety of psychiatric disorders such as Autism Spectrum Disorder (ASD) and depression. Methyl donors such as S-Adenosyl-Methionine (SAMe) may cause epigenetic modifications, especially during embryonic development when the epigenetic memory is established. We treated pregnant submissive (Sub) mice exhibiting depressive-like phenotype with SAMe during days 12-14 of gestation aiming to alleviate the depressive - like symptoms in their offspring and normalize the expression in their prefrontal cortex of several genes possibly involved in depression. We also aimed to define possible gender differences of the effects of SAMe on the measured parameters. Treatment of the Dams with SAMe did not affect the early neurodevelopmental milestones in males or females. The results of the behavioral tests showed improvement in some behavioral parameters compared to saline treated Sub mice. Several of these improvements were gender related. Prenatal SAMe treatment mainly improved sociability, as observed in the three chambers social interaction test, in both genders. It also improved the increased locomotion (as observed by the open field test) in the female mice, but not in males. Prenatal SAMe increased the expression of Vegfa and Flt1 in males, but not in females. The expression of IgfII and SynIIb increased in males and decreased in females and the expression of serotonin receptor Htr2A did not change in both genders. In our mouse model of depression, prenatal treatment with SAMe significantly improved some parameters of depressive like behavior and normalized the expression of several genes related to depression. The gender differences observed in our studies may explain the sex related differences in the clinical presentation of depression and the different gender related response to treatment.