Altered Structural Plasticity Mediated by mGlu and NMDA Receptors and Impaired Cognition in a Genetic ASD Model (Shank3Mice).

Abstract

Dendritic spine morphology is strongly associated with neurodevelopmental disorders. Synaptic plasticity alters spine volume, a phenomenon known as structural plasticity, which influences information processing within neuronal circuits. Structural changes at dendritic spines are linked to autism spectrum disorders, particularly those involving gene mutations that result in synaptopathy. Loss of a single copy of thegene leads to Phelan-McDermid syndrome, a synaptopathy, asencodes SHANK3, a scaffold protein in the postsynaptic density of glutamatergic neurons. In this study, the structural plasticity of dendritic spines was evaluated in male and female Shank3and wild-type mice in response to synaptic plasticity. Two-photon imaging and glutamate uncaging were employed in organotypic hippocampal cultures. Cognitive function in adult Shank3mice was also assessed using a novel object recognition test. The results indicate that Shank3mice exhibit altered structural plasticity in response to long-term depression and display a heterosynaptic response in neighboring spines. Increased GluN2B expression and-methyl-d-aspartate currents underlie these effects and may influence object recognition memory in Shank3mice. These findings suggest thathaploinsufficiency induces synaptic alterations during postnatal development that impact memory in adulthood.