Srcap Haploinsufficiency Induced Autistic-Like Behaviors in Mice through Disruption of Satb2 Expression

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with significant genetic predispositions. Among these, loss-of-function mutations of the chromatin remodeling gene SRCAP have been identified in individuals with ASD, but their pathogenic mechanisms have yet to be fully elucidated. In this study, we established a germline mutant mouse model harboring a heterozygous frameshift mutation in the Srcap gene (Srcap+/-). The Srcap+/- mice exhibited notable impairments in social novelty, repetitive and stereotyped behaviors, anxiety, and learning and memory deficits. We observed a decreased number of parvalbumin (PV)-expressing neurons in their retrosplenial cortex (RSC) and dentate gyrus (DG). Furthermore, abnormalities in dendritic structure, synaptic density, and synaptic transmission were noted in the DG of Srcap+/- mice. RNA sequencing revealed that the expression of 27 genes, implicated in ASD, was dysregulated in the Srcap haploinsufficiency mice. Among these genes, we found that Srcap haploinsufficiency resulted in decreased Satb2 expression due to diminished H2A.z-binding within the promoter region of Satb2. Remarkably, intervention through retro-orbital injection of AAV vectors expressing Satb2 in newborn Srcap+/- mice reversed autistic-like behaviors and developmental defects in the RSC and DG regions. Similarly, in adolescent Srcap+/- mice, stereotactic injection of AAV expressing Satb2 into the RSC ameliorated deficits in social novelty. Collectively, these findings highlight the crucial role of the Srcap in neurodevelopment by regulating Satb2 expression, particularly impacting the development of RSC and DG regions.