The interaction of Synapsin 2a and Synaptogyrin-3 regulates fear extinction in mice
Xi-Ya Shen, … , Ling-Qiang Zhu, Dan Liu
Xi-Ya Shen, … , Ling-Qiang Zhu, Dan Liu
Published January 4, 2024
Citation Information: J Clin Invest. 2024;134(4):e172802. https://doi.org/10.1172/JCI172802.
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Research Article Neuroscience

The interaction of Synapsin 2a and Synaptogyrin-3 regulates fear extinction in mice

Abstract

The mechanisms behind a lack of efficient fear extinction in some individuals are unclear. Here, by employing a principal components analysis–based approach, we differentiated the mice into extinction-resistant and susceptible groups. We determined that elevated synapsin 2a (Syn2a) in the infralimbic cortex (IL) to basolateral amygdala (BLA) circuit disrupted presynaptic orchestration, leading to an excitatory/inhibitory imbalance in the BLA region and causing extinction resistance. Overexpression or silencing of Syn2a levels in IL neurons replicated or alleviated behavioral, electrophysiological, and biochemical phenotypes in resistant mice. We further identified that the proline-rich domain H in the C-terminus of Syn2a was indispensable for the interaction with synaptogyrin-3 (Syngr3) and demonstrated that disrupting this interaction restored extinction impairments. Molecular docking revealed that ritonavir, an FDA-approved HIV drug, could disrupt Syn2a-Syngr3 binding and rescue fear extinction behavior in Syn2a-elevated mice. In summary, the aberrant elevation of Syn2a expression and its interaction with Syngr3 at the presynaptic site were crucial in fear extinction resistance, suggesting a potential therapeutic avenue for related disorders.

Authors

Xi-Ya Shen, Juan Zhang, He-Zhou Huang, Shao-Dan Li, Ling Zhou, Shi-Ping Wu, Cheng Tang, Xian Huang, Zhi-Qiang Liu, Zi-Yuan Guo, Xiang Li, Heng-Ye Man, You-Ming Lu, Ling-Qiang Zhu, Dan Liu

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Figure 6

Syn2a interacts with AA91-99 of Syngr3 via domain H.

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Syn2a interacts with AA91-99 of Syngr3 via domain H. (A) Co-IP of Syn2a ...
(A) Co-IP of Syn2a and Syngr3 from the presynaptic fraction of amygdala homogenates of naive mice (n = 3 replicates). IP, immunoprecipitation; IB, immunoblotting. (B) Co-IP and quantitative analysis to evaluate the binding of Syn2a and Syngr3 from EXT-S and EXT-R mouse mPFC lysates (n = 3 replicates). (C) H293T cells were transiently transfected with the EGFP-Syn2a, EGFP-Syn2a-ΔH, EGFP-Syn2a-ΔE, and full-length Syngr3 [Syngr3(fl)-HA] plasmids. The cell lysates were collected and immunoprecipitated with an anti-HA antibody. Western blotting was performed using anti-HA and anti-EGFP antibodies. (D) H293T cell were transiently transfected with the Syngr3 (fl)-HA, Syngr3 (1-148)-HA, Syngr3 (149-229)-HA, Syngr3 (1-90)-HA or Syngr3 (91-148)-HA, and EGFP-domain H plasmids. The cell lysates were collected and immunoprecipitated with an anti-HA antibody. Western blot was performed by using anti-HA and anti-EGFP antibodies. (E) H293T cells were transiently transfected with the Syngr3 (fl)-HA, Syngr3 (deletion 91-148)-HA, Syngr3 (deletion 91–99)-HA, Syngr3 (deletion 133–148)-HA, and EGFP-domain H plasmids. The cell lysates were collected and immunoprecipitated with an anti-EGFP antibody. Western blot was performed by using anti-HA and anti-EGFP antibodies. (F) Quantitative analysis of Co-IP using the anti-EGFP antibody (n = 3 replicates). Statistical analyses among multiple groups were conducted using 1-way ANOVA followed by Bonferroni post hoc tests (F), whereas an unpaired 2-tailed t test was conducted for comparing 2 groups (B). ***P < 0.001. Values are presented as mean ± SEM.