Humanized substitutions of Vmat1 in mice alter amygdala-dependent behaviors associated with the evolution of anxiety

Daiki X Sato; Yukiko U Inoue; Nahoko Kuga; Satoko Hattori; Kensaku Nomoto; Yuki Morimoto; Giovanni Sala; Hideo Hagihara; Takefumi Kikusui; Takuya Sasaki; Yuji Ikegaya; Tsuyoshi Miyakawa; Takayoshi Inoue; Masakado Kawata

doi:10.1016/j.isci.2022.104800

Humanized substitutions of Vmat1 in mice alter amygdala-dependent behaviors associated with the evolution of anxiety

iScience. 2022 Jul 20;25(8):104800. doi: 10.1016/j.isci.2022.104800. eCollection 2022 Aug 19.

Authors

Daiki X Sato^{1

2}, Yukiko U Inoue³, Nahoko Kuga^{4

5}, Satoko Hattori², Kensaku Nomoto⁶, Yuki Morimoto³, Giovanni Sala², Hideo Hagihara², Takefumi Kikusui⁷, Takuya Sasaki^{4

5

8}, Yuji Ikegaya^{4

9

10}, Tsuyoshi Miyakawa², Takayoshi Inoue³, Masakado Kawata¹

Affiliations

¹ Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.
² Division of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
³ Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan.
⁴ Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan.
⁵ Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.
⁶ Department of Physiology, Dokkyo Medical University, Mibu, Tochigi, 321-0293, Japan.
⁷ Department of Animal Science and Biotechnology, Azabu University, Sagamihara, Kanagawa, Japan.
⁸ Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
⁹ Center for Information and Neural Networks, National Institute of Information and Communications Technology, 1-4 Yamadaoka, Suita City, Osaka 565-0871, Japan.
¹⁰ Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan.

Abstract

The human vesicular monoamine transporter 1 (VMAT1) harbors unique substitutions (Asn136Thr/Ile) that affect monoamine uptake into synaptic vesicles. These substitutions are absent in all known mammals, suggesting their contributions to distinct aspects of human behavior modulated by monoaminergic transmissions, such as emotion and cognition. To directly test the impact of these human-specific mutations, we introduced the humanized residues into mouse Vmat1 via CRISPR/Cas9-mediated genome editing and examined changes at the behavioral, neurophysiological, and molecular levels. Behavioral tests revealed reduced anxiety-related traits of Vmat1 ^Ile mice, consistent with human studies, and electrophysiological recordings showed altered oscillatory activity in the amygdala under anxiogenic conditions. Transcriptome analyses further identified changes in gene expressions in the amygdala involved in neurodevelopment and emotional regulation, which may corroborate the observed phenotypes. This knock-in mouse model hence provides compelling evidence that the mutations affecting monoaminergic signaling and amygdala circuits have contributed to the evolution of human socio-emotional behaviors.

Keywords: Behavior genetics; Evolutionary biology; Molecular Genetics; Molecular mechanism of behavior.