Adult Restoration of Shank3 Expression Rescues Selective Autistic-Like Phenotypes

Abstract

Because ASD is a neurodevelopmental disorder and patients typically display symptoms before the age of three ¹ , one of the key questions in autism research is whether the pathology is reversible in adults. Here we investigated the developmental requirement of Shank3, one of the most prominent monogenic ASD genes that is estimated to contribute to ~1% of all ASD cases ^{2– 6} . SHANK3 is a postsynaptic scaffold protein that regulates synaptic development, function and plasticity by orchestrating the assembly of postsynaptic density (PSD) macromolecular signaling complex ^{7– 9} . Disruptions of the Shank3 gene in mouse models have resulted in synaptic defects and autistic-like behaviors including anxiety, social interaction deficits, and repetitive behavior ^{10– 13} . We generated a novel Shank3 conditional knock-in mouse model and used it to demonstrate that re-expression of the Shank3 gene in adult led to improvements in synaptic protein composition, spine density and neural function in the striatum. We also provided behavioral evidence that certain behavioral abnormalities including social interaction deficit and repetitive grooming behavior could be rescued, while anxiety and motor coordination deficit could not be recovered in adulthood. Together, these results elucidate the profound impact of post-developmental activation of Shank3 expression on neural function and demonstrate certain degree of continued plasticity in the adult diseased brain.