Bazedoxifene rescues sexually dimorphic autistic-like abnormalities in mice carrying a biallelic MDGA1 mutation

In the accompanying study, we describe two pairs of MDGA1 missense mutations (Val116Met/Ala688Val and Tyr635Cys/Glu756Gln) from two patients with autism spectrum disorders (ASDs) and how these mutations exert distinct abnormalities in biological processes during central nervous system development. Here, we generated knockin (KI) mice harboring the murine version of Tyr635Cys/Glu756Gln MDGA1 (Mdga1Y636C/E751Q) and performed extensive behavioral analyses. Male KI mouse pups and adults exhibited impaired ultrasonic vocalizations and sensorimotor gating (ASD-relevant behavioral deficits), and thus exhibited phenotypes different from those of male Mdga1 conditional knockout (cKO) mice. In contrast, adult female KI mice did not exhibit a range of ASD-like behavioral abnormalities. Electrophysiological analyses performed using both juvenile and adult Mdga1Y636C/E751Q mice revealed sexually dimorphic and developmental stage-dependent compromises of GABAergic synaptic inhibition. In addition, proteomics analyses showed that the phospho-proteomic phenotypes differed between Mdga1Y636C/E751Q and Mdga1-cKO mice. Treatment of male Mdga1Y636C/E751Q KI mice with the FDA-approved estrogen receptor modulator, bazedoxifene, restores the KI-related molecular, GABAergic synapse, and behavioral changes. Collectively, our results suggest a novel treatment strategy for ASDs that present developmentally regulated and/or sexually dimorphic features.