Retinoic acid supplementation rescues the social deficits in Fmr1 knockout mice

Autism spectrum disorder (ASD) is a hereditary intellectual disability. Fragile X syndrome (FXS) is the leading cause of ASD and mainly results from the abnormal CGG amplification (>200 repeats) of the fragile X mental retardation 1 (Fmr1) gene. All-trans retinoic acid (RA) is involved in synaptic plasticity, neuronal differentiation and brain maturation. RA-mediated synaptic strength regulation was abolished in FXS patient-derived induced pluripotent stem (iPS) cells. Previous work on the ASD model with excessive UBE3A expression, of which the ASD-like behaviors caused by repression in RA signaling were successfully ameliorated by oral supplementation of RA. In this study, we used male Fmr1 knock-out (KO) mice to explore the effect of RA exerting on the behaviors. Our results indicated that RA supplementation can alleviate the defects in social novelty. We performed RNA sequencing to find out the differentially expressed genes (DEGs) in the Fmr1 KO group, of which the expression levels were restored to the similar level as those in the wild-type (WT) group after RA supplementation, such as Per1, Per2 and Foxp2. Besides, several DEGs associated with neuronal functions were also identified, like Arc, Ccn2, Foxp2, Xdh, Lepr, Serpina3n andTnfsf10. our findings that RA supplementation improved social novelty behavior in Fmr1 KO mice provided a potential therapeutic intervention method for FXS, which may further be used in other disease models with defective RA signaling. mRNA sequencing data of prefrontal cortex tissue from six WTmale mice treated with Oil; six WTmale mice treated with RA; and six KO male mice treated with Oil; six KO male mice treated with RA. Two mice of the same genotype and treatment were pooled together as one sample. A total of three samples from six male mice were used for high-throughput sequencing in each group, including WT+Oil; WT+RA;Fmr1 KO+Oil; Fmr1 KO+RA.