Mice lacking Astn2 have ASD-like behaviors and altered cerebellar circuit properties

Hanzel, M.; Fernando, K.; Maloney, S. E.; Gong, S.; Mätlik, K.; Zhao, J.; Pasolli, H. A.; Heissel, S.; Dougherty, J. D.; Hull, C.; Hatten, M. E.

doi:10.1101/2024.02.18.580354

bioRxiv · 10.1101/2024.02.18.580354

Mice lacking Astn2 have ASD-like behaviors and altered cerebellar circuit properties

Hanzel, M.·Fernando, K.·Maloney, S. E.·Gong, S.·Mätlik, K.·Zhao, J.·Pasolli, H. A.·Heissel, S.·Dougherty, J. D.·Hull, C.·Hatten, M. E.

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Abstract

Astrotactin 2 (ASTN2) is a transmembrane neuronal protein highly expressed in the cerebellum that functions in receptor trafficking and modulates cerebellar Purkinje cell (PC) synaptic activity. We recently reported a family with a paternally inherited intragenic ASTN2 duplication with a range of neurodevelopmental disorders, including autism spectrum disorder (ASD), learning difficulties, and speech and language delay. To provide a genetic model for the role of the cerebellum in ASD-related behaviors and study the role of ASTN2 in cerebellar circuit function, we generated global and PC-specific conditional Astn2 knockout (KO and cKO, respectively) mouse lines. Astn2 KO mice exhibit strong ASD-related behavioral phenotypes, including a marked decrease in separation-induced pup ultrasonic vocalization calls, hyperactivity and repetitive behaviors, altered social behaviors, and impaired cerebellar-dependent eyeblink conditioning. Hyperactivity and repetitive behaviors were also prominent in Astn2 cKO animals. By Golgi staining, Astn2 KO PCs have region-specific changes in dendritic spine density and filopodia numbers. Proteomic analysis of Astn2 KO cerebellum reveals a marked upregulation of ASTN2 family member, ASTN1, a neuron-glial adhesion protein. Immunohistochemistry and electron microscopy demonstrates a significant increase in Bergmann glia volume in the molecular layer of Astn2 KO animals. Electrophysiological experiments indicate a reduced frequency of spontaneous excitatory postsynaptic currents (EPSCs), as well as increased amplitudes of both spontaneous EPSCs and inhibitory postsynaptic currents (IPSCs) in the Astn2 KO animals, suggesting that pre- and postsynaptic components of synaptic transmission are altered. Thus, ASTN2 regulates ASD-like behaviors and cerebellar circuit properties.

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Hanzel, M., Fernando, K., Maloney, S. E., Gong, S., Mätlik, K., Zhao, J., Pasolli, H. A., Heissel, S., Dougherty, J. D., Hull, C., Hatten, M. E.. 2024-02-18. Mice lacking Astn2 have ASD-like behaviors and altered cerebellar circuit properties. https://doi.org/10.1101/2024.02.18.580354

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