Major motor and gait deficits with sexual dimorphism in a Shank3 mutant mouse model

Abstract

Background Contrasting findings were reported in several animal models with a Shank3 mutation used to induce various autism spectrum disorder (ASD) symptoms. Here, we aimed at investigating behavioral, cellular, and molecular consequences of a C-terminal (frameshift in exon 21) deletion in Shank3 protein in mice, a mutation that is also found in clinical conditions and which results in loss of major isoforms of Shank3. A special focus was made on cerebellar related parameters. Methods All three genotypes were analyzed [wild type (WT), heterozygote (Shank3+/ΔC) and homozygote (Shank3 ΔC/ΔC)] and males and females were separated into two distinct groups. Motor and social behavior, gait, Purkinje cells (PC) and glutamatergic protein levels were determined. Behavioral and cellular procedures used here were previously validated using two environmental animal models of ASD. ANOVA and post-hoc analysis were used for statistical analysis. Results Shank3 ΔC/ΔC mice showed significant impairments in social novelty preference, stereotyped behavior and gait. These were accompanied by a decreased number of PC in restricted cerebellar sub-regions and decreased cerebellar expression of mGluR5. Females Shank3 ΔC/ΔC were less affected by the mutation than males. Shank3+/ΔC mice showed impairments only in social novelty preference, grooming, and decreased mGluR5 expression and that were to a much lesser extent than in Shank3 ΔC/ΔC mice. Limitations As Shank3 mutation is a haploinsufficiency, it is of interest to emphasize that Shank3+/ΔC mice showed only mild to no deficiencies compared to Shank3 ΔC/ΔC. Conclusions Our findings indicate that several behavioral, cellular, and molecular parameters are affected in this animal model. The reported deficits are more pronounced in males than in females. Additionally, male Shank3 ΔC/ΔC mice show more pronounced alterations than Shank3+/ΔC. Together with our previous findings in two environmental animal models of ASD, our studies indicate that gait dysfunction constitutes a robust set of motor ASD symptoms that may be considered for implementation in clinical settings as an early and quantitative diagnosis criteria.

Early life sleep disruption potentiates lasting sex-specific changes in behavior in genetically vulnerable Shank3 heterozygous autism model mice

“…In the control treatment group, we did not observe any differences in behavior between WT and Shank3 WT/ΔC littermates (Figs. 3 and 4), consistent with several previous reports 13-17 , suggesting that loss of a single copy of Shank3 alone is insufficient to induce robust ASD relevant phenotypes in mice. Strikingly, we observed that ELSD treatment, but not PASD treatment, resulted in lasting changes in behavior in genetically vulnerable Shank3 WT/ΔC heterozygotes, while WT littermates were resistant.…”

“…Heterozygous mutation or chromosomal loss of SHANK3 is causative of Phelan-McDermid syndrome, a severe neurodevelopmental condition with associated autism and sleep disruption 11,12 . ASD model mice with homozygous mutations in Shank3 exhibit a variety of ASD-relevant phenotypes, while the more clinically relevant Shank3 heterozygotes show no or mild phenotypes 13-17 , often leading to the use of Shank3 homozygous mice as a preferred research model. A recent study has documented that adult male mice with homozygous C-terminal truncation of Shank3 ( Shank3 ΔC/ΔC ) show clear sleep disruption, reminiscent of patients with Phelan-McDermid syndrome 18 .…”

Comparison of SHANK3 deficiency in animal models: phenotypes, treatment strategies, and translational implications

“…Increased self grooming and other repetitive behaviors have been consistently reported in the models ex4-22|ALL [ 128 – 130 ], ex11|SH3 [ 123 ], ex13|PDZ [ 139 , 176 ], ex13-16|PDZ [ 83 , 90 , 155 , 159 , 160 , 162 – 164 , 166 , 168 , 181 – 183 ], ex14-16|PDZ [ 131 ], ex21|PRO [ 125 , 178 , 179 ], and ex11-21|SH3-PRO in rats [ 135 ]. Interestingly, in murine models ex21|PRO-InsG3680 [ 127 ] and ex8|ANK-Q321R [ 132 ], which mimick ASD-associated mutations, increased repetitive behavior was observed, whereas this was not the case in ex21|PRO-R1117X [ 127 ] mice, which harbor a schizophrenia-associated mutation.…”

“…Cre-expression, and thus deletion of Shank3 in neocortical excitatory neurons (ex4-22|ALL-NEX Cre ), Dlx5/6 -positive GABAergic forebrain neurons (ex4-22|ALL-Dlx5/6 Cre ), which include various subclasses of neocortical interneurons but also MSNs as principal striatal projection neurons [ 169 – 174 ], DRD1- (ex4-22|ALL-Drd1 Cre ) and DRD2-positive neurons (ex4-22|ALL-Drd2 Cre ) [ 129 ], did not induce the phenotype previously observed in the constitutive KO model [ 128 ], though it has to be noted that such deficits of constitutive KO mice were also not replicated in this study. Mixed evidence and even conflicting results concerning social interaction deficits were observed in the models ex9|ANK [ 82 , 175 ], ex13|PDZ [ 139 , 176 ], ex21|PRO [ 125 , 177 – 179 ], and the rat model ex6|ANK [ 134 , 180 ]. Intact social motivation and interaction was described in the analysis of the models ex4-7|ANK [ 90 ], ex8|ANK-Q321R [ 132 ], ex21|PRO-InsG3728 [ 126 ], and ex11-21|SH3-PRO in rats [ 135 ].…”

“…Such deficits of social recognition were observed in the animals of ex4-22|ALL [ 128 ], ex4-7|ANK [ 90 ], ex11|SH3 [ 123 ], ex13|PDZ [ 139 , 176 ], ex21|PRO [ 125 , 178 , 179 ], and the rat models ex6|ANK [ 134 ] or ex11-21|SH3-PRO [ 135 ]. A single study on the model ex21|PRO did not replicate the abovementioned deficits [ 177 ].…”