BACKGROUND Anaesthesia has been shown to impair social functioning, but the underlying mechanisms remain largely unknown. The volatile anaesthetic isoflurane potentially disrupts the methionine cycle and trans-sulphuration pathway, contributing to social deficits. Cystathionine-β-synthase (CBS), a key enzyme in this pathway, might be targeted by isoflurane. We investigated the CBS-isoflurane interaction and its role in neuronal function and social behaviour. METHODS Mice aged 3-15 months were anaesthetised with 2 vol% isoflurane for 2 h, and social behaviours were tested 24 h after exposure. Alterations in neuronal activity were assessed using electrophysiological analysis in vivo. Pharmacological activators (S-adenosylmethionine [SAM]) or inhibitors (amino-oxyacetic acid [AOAA]), and adeno-associated virus (AAV) were used to modulate CBS activity. The binding site of isoflurane on CBS was determined using X-ray crystallography. A novel transgenic model with a point mutation knock-in was constructed to eliminate the CBS-isoflurane interaction. RESULTS Isoflurane inhibited CBS activity (by 0.35-fold [0.07] vs 1.00-fold [0.05]; P<0.001), leading to neuronal hypoactivity in the anterior cingulate cortex (ACC) and social impairments in adult and elderly mice. SAM, AOAA, and AAV interventions demonstrated a causal link. Structural and functional analysis identified the lysine 273 (K273) in CBS to be involved in isoflurane inhibition. CBS K273A knock-in mice exhibited increased CBS activity compared with wild-type littermates after isoflurane exposure (2.2-fold [0.22] vs 1.0-fold [0.28]; P<0.001), with successful alleviation of ACC neuronal hypoactivity and social dysfunction. CONCLUSIONS These findings reveal a crucial role for CBS inhibition by isoflurane in anaesthesia-induced social impairment.

中文翻译：

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异氟醚抑制胱硫醚-β-合酶的结构基础及其在麻醉诱导的小鼠社交功能障碍中的作用。


背景 麻醉已被证明会损害社会功能，但其潜在机制在很大程度上仍是未知的。挥发性麻醉剂异氟醚可能会破坏蛋氨酸循环和反式硫化途径，从而导致社会缺陷。胱硫醚-β-合酶 （CBS） 是该通路中的关键酶，可能以异氟醚为靶点。我们研究了 CBS-isoflurane 相互作用及其在神经元功能和社会行为中的作用。方法 3-15 月龄小鼠用 2 vol% 异氟醚麻醉 2 h，暴露后 24 h 测试社交行为。使用体内电生理分析评估神经元活性的改变。使用药理学激活剂 （S-腺苷甲硫氨酸 [SAM]）或抑制剂 （氨基氧乙酸 [AOAA]） 和腺相关病毒 （AAV） 来调节 CBS 活性。使用 X 射线晶体学确定异氟醚在 CBS 上的结合位点。构建了一种具有点突变敲入的新型转基因模型，以消除 CBS-isoflurane 相互作用。结果 异氟醚抑制 CBS 活性 （0.35 倍 [0.07] 对 1.00 倍 [0.05];P<0.001），导致前扣带皮层 （ACC） 神经元活动减退以及成年和老年小鼠的社交障碍。SAM、AOAA 和 AAV 干预证明了因果关系。结构和功能分析确定 CBS 中的赖氨酸 273 （K273） 参与异氟醚抑制。与野生型同窝小鼠相比，CBS K273A 敲入小鼠在异氟醚暴露后表现出更高的 CBS 活性 （2.2 倍 [0.22] 对 1.0 倍 [0.28];P<0.001），成功缓解 ACC 神经元活动减退和社交功能障碍。 结论 这些发现揭示了异氟醚抑制 CBS 在麻醉诱导的社交障碍中的关键作用。