Autism-like Behavior In Mice With Deletion Of The Cacna2d3 Gene In Parvalbumin Neurons

BackgroundAutism spectrum disorder（ASD）is a neurodevelopmental disorder that core symptoms are social impairment and repetitive stereotypical behaviour.The prevalence of autism is increasing every year.The CACNA2D3 gene,which encodes the voltage-gated calcium channel（VGCC）subunitα2δ3 protein,is a risk gene for ASD.It has also been suggested thatγ-aminobutyric acid（GABA）interneuron dysfunction is associated with ASD.There is a lack of understanding of the role of GABAergic interneurons in CACNA2D3 gene-associated autism.ObjectiveTherefore,we specifically knocked out the Cacna2d3 gene in different types of GABAergic interneurons in mice to explore the autism-like behavioural phenotype associated with Cacna2d3 gene deletion in different interneurons of mice and the mechanism of GABAergic interneurons in Cacna2d3 gene-associated autism.MethodsIn this study,PV^Cre;Cacna2d3^f/fand SOM^Cre;Cacna2d3^f/fmice and littermate control mice were generated on C57BL/6 mice using the Cre-lox P recombinase system.The newborn mice were genotyped by PCR and agarose gel electrophoresis.Expression of CACNA2D3,PV,GAD67 and c-Fos in brain tissue was detected by Western blot and Immunofluorescence staining.The mice were examined for anxiety in the open-field and elevated experiments,social behaviour in the three chambers social experiment,repetitive stereotyped behaviour in the marble burying and nesting experiments,recognition memory in the new location recognition and new object recognition experiments,and spatial learning memory in the Morris water maze（MWM）water maze.ResultsGenotyping,Western blot and Immunofluorescence staining showed that two types of conditional knockout（CKO）mouse models were successfully constructed:PV^Cre;Cacna2d3^f/fmice and SOM^Cre;Cacna2d3^f/fmice.（2）Compared to littermates,PV^Cre;Cacna2d3^f/fmice showed increased anxiety-like behavior in the open field,while SOM^Cre;Cacna2d3^f/fmice showed no change;（3）PV^Cre;Cacna2d3^f/fmice were significantly less interested in unfamiliar mice in the three chambers social experiment than littermate control mice and there was no difference in the level of interest in new unfamiliar mice between the two groups in the social novelty experiment.SOM^Cre;Cacna2d3^f/fmice performed no differently from control mice;（4）Compared to littermates,PV^Cre;Cacna2d3^f/fmice showed increased repetitive stereotyped behaviour in marble burying test,while SOM^Cre;Cacna2d3^f/fmice showed no change;（5）PV^Cre;Cacna2d3^f/fmice show impaired recognition memory in the new location recognition and new object recognition experiments;（6）In the MWM experiment,PV^Cre;Cacna2d3^f/fmice had better spatial memory compared to littermate control mice;（7）PV and glutamic acid decarboxylase 67（GAD67）protein expression in the prefrontal cortex of PV^Cre;Cacna2d3^f/fmice was significantly lower than that of littermate control mice,PV expression in the striatum was significantly lower than that of littermate control mice;and GAD67 was unchanged.GAD67 expression in the prefrontal cortex of SOM^Cre;Cacna2d3^f/fmice was not significantly different compared to littermates.ConclusionsSpecific knockout of the Cacna2d3 gene on PV neurons in mice results in autistic-like behavioural phenotypes,include social dysfunction and repetitive stereotypes,accompanied by anxiety,impaired recognition memory and enhanced spatial memory.These behavioural phenotypes may be due to PV neuronal dysfunction,causing a de-inhibitory effect in the prefrontal cortex.We did not observe an autism-like phenotype or de-inhibition in the prefrontal cortex in mice with specific knockout of the Cacna2d3gene on SOM interneurons.