The PDE10A Inhibitor TAK-063 Reverses Sound-Evoked EEG Abnormalities in a Mouse Model of Fragile X Syndrome.

Fragile X syndrome (FXS) is a genetic neurodevelopmental syndrome characterized by increased anxiety, repetitive behaviors, social communication deficits, delayed language development, and abnormal sensory processing. Recently, we have identified electroencephalographic (EEG) biomarkers that are conserved between the mouse model of FXS (Fmr1 KO mice) and humans with FXS. In this study, we test a specific candidate mechanism for engagement of multielectrode array (MEA) EEG biomarkers in the FXS mouse model. We administered TAK-063, a potent, selective, and orally active phosphodiesterase 10A (PDE10A) inhibitor, to Fmr1 KO mice, and examined its effects on MEA EEG biomarkers. We demonstrate significant dose-related amelioration of inter-trial phase coherence (ITPC) to temporally modulated auditory stimuli by TAK-063 in Fmr1 KO mice. Our data suggest that TAK-063 improves cortical auditory stimulus processing in Fmr1 KO mice, without significantly depressing baseline EEG power or causing any noticeable sedation or behavioral side effects. Thus, the PDE10A inhibitor TAK-063 has salutary effects on normalizing EEG biomarkers in a mouse model of FXS and should be pursued in further translational treatment development.