Biology subjects

Kang, S. J.

Publications and source records attributed to Kang, S. J..

4 recordsLinked to original sources

bioRxiv2026

Acute social defeat induces cannabinoid type 1 receptor-dependent synaptic depression in the anterior ventral subiculum to anterior hypothalamic nucleus pathway to drive social avoidance in male mice

BACKGROUND: Social avoidance is a protective response that limits exposure to harmful social stimuli. Although avoidance is a characteristic stress phenotype, its circuit-level regulation remains unclear. The ventral subiculum (vSUB), a major hippocampal output, projects to the anterior hypothalamic nucleus (AHN), a key region for stress responses. METHODS: Male mice underwent acute social defeat stress (ASDS) or subthreshold social defeat stress. We combined social interaction, open field, and elevated plus maze testing with optogenetic-assisted slice recording, pharmacology, pathway-specific chemogenetics and optogenetics, retrograde and anterograde transsynaptic tracing, and in situ hybridization. RESULTS: ASDS induced presynaptic depression at anterior vSUB (avSUB) [->] AHN synapses through a glucocorticoid- and cannabinoid type 1 receptor (CB1R)-dependent mechanism, while posterior vSUB (pvSUB) [->] AHN synapses were unaffected. Infusing a CB1R antagonist into the AHN before ASDS attenuated both the synaptic depression and the social avoidance. Chemogenetic activation of the avSUB [->] AHN pathway during ASDS attenuated social avoidance, whereas its inhibition induced avoidance under subthreshold stress. Optogenetic activation of the avSUB [->] AHN pathway produced an immediate increase in social approach. Anterograde tracing revealed that anterior and posterior vSUB neurons project to largely separate AHN populations. The pvSUB [->] AHN pathway modulates anxiety-like behavior without altering social approach. CONCLUSIONS: These findings reveal specialized roles for vSUB subregions in social and emotional responses, and identify presynaptic gating of the avSUB [->] AHN synapse as a control point for stress-induced social withdrawal.

neuroscience↗

bioRxiv2024

Encoding opposing valences through frequency-dependent transmitter switching in single peptidergic neurons

Peptidergic neurons often co-express fast transmitters and neuropeptides in separate vesicles with distinct release properties. However, the release dynamics of each transmitter in various contexts have not been fully understood in behaving animals. Here, we demonstrate that calcitonin gene-related peptide (CGRP) neurons in the external lateral subdivision of the parabrachial nucleus (CGRPPBel) encode opposing valence via differential release, rather than corelease, of glutamate and neuropeptides, according to firing rate. Glutamate is released preferentially at lower firing rates with minimal release at higher firing rates, whereas neuropeptides are released at higher firing rates, resulting in frequency-dependent switching of transmitters. Aversive stimuli evoke high frequency responses with accompanying neuropeptide release to encode negative valence, whereas appetitive stimuli evoke low frequency responses with glutamate release to encode positive valence. Our study reveals a previously unknown capability of single CGRPPBel neurons to bidirectionally encode valence via frequency-dependent differential release of transmitters in vivo.

neuroscience↗

bioRxiv2022

Isolation and characterization of a neoxanthin synthase gene functioning in fucoxanthin biosynthesis of Phaeodactyum tricornutum

Golden-brown xanthophyll fucoxanthin in marine organisms, especially in diatoms, has attracted widespread attention because of its diverse biological activities. However, the biosynthetic pathway of fucoxanthin remains unclear in diatoms. Fucoxanthin may derive from either neoxanthin or diadinoxanthin pathway. However, the key point is whether neoxanthin and its synthesizing genes exist or not. In this study, we successfully identified a few xanthophylls in trace amounts in the concentrated fraction of carotenoids of diatom Phaeodactylum tricornutum cultured at different light intensities with the co-chromatography method, and cloned the neoxanthin synthase (NXS) gene which was not annotated in diatom genome. The NXS knockdown and knockout experiment show a positive correlation in the accumulation of neoxanthin and zeaxanthin while a negative correlation in violaxanthin and fucoxanthin with the expression of NXS. In vitro assay evidenced that neoxanthin is the precursor for fucoxanthin biosynthesis, indicating that other molecules intermediate the conversion between violaxanthin and fucoxanthin. Overall, we cloned a novel gene functioning in neoxanthin biosynthesis, which should aid to clarifying the fucoxanthin biosynthetic pathway in diatom.

molecular biology↗

bioRxiv2020

Unified neural pathways that gate affective pain and multisensory innate threat signals to the amygdala

Perception of aversive sensory stimuli such as pain and innate threat cues is essential for animal survival. The amygdala is critical for aversive sensory perception, and it has been suggested that multiple parallel pathways independently relay aversive cues from each sensory modality to the amygdala. However, a convergent pathway that relays multisensory aversive cues to the amygdala has not been identified. Here, we report that neurons expressing calcitonin gene-related peptide (CGRP) in the parvocellular subparafasicular thalamic nucleus (SPFp) are necessary and sufficient for affective-motivational pain perception by forming a spino-thalamo-amygdaloid pain pathway. In addition, we find that this thalamic CGRP pain pathway, together with well-known parabrachio-amygdaloid CGRP pain pathway, is critical for the perception of multisensory innate threat cues. The discovery of unified pathways that collectively gate aversive sensory stimuli from all sensory modalities may provide critical circuit-based insights for developing therapeutic interventions for affective pain- and innate fear-related disorders.

neuroscience↗