Autism spectrum disorder (ASD) is a highly heritable complex neurodevelopmental disorder. While the core symptoms of ASD are defects of social interaction and repetitive behaviors, over 50% of ASD patients have comorbidity of intellectual disabilities (ID) or developmental delay (DD), raising the question whether there are genetic components and neural circuits specific for core symptoms of ASD. Here, by focusing on ASD patients who do not show compound ID or DD, we identified a de novo heterozygous gene-truncating mutation of the Sentrin-specific peptidase1 (SENP1) gene, coding the small ubiquitin-like modifiers (SUMO) deconjugating enzyme, as a potentially new candidate gene for ASD. We found that Senp1 haploinsufficient mice exhibited core symptoms of autism such as deficits in social interaction and repetitive behaviors, but normal learning and memory ability. Moreover, we found that the inhibitory and excitatory synaptic functions were severely affected in the retrosplenial agranular (RSA) cortex of Senp1 haploinsufficient mice. Lack of Senp1 led to over SUMOylation and degradation of fragile X mental retardation protein (FMRP) proteins, which is coded by the FMR1 gene, also implicated in syndromic autism. Importantly, re-introducing SENP1 or FMRP specifically in RSA fully rescued the defects of synaptic functions and core autistic-like symptoms of Senp1 haploinsufficient mice. Taken together, these results elucidate that disruption of the SENP1-FMRP regulatory axis in the RSA may cause core autistic symptoms, which further provide a candidate brain region for therapeutic intervene of ASD by neural modulation approaches.
bioRxiv Subject Collection: Neuroscience