七氟醚通过作用于泛素化-蛋白酶体途径降低幼鼠突触后致密蛋白95的水平。
Sevoflurane Acts on Ubiquitination-Proteasome Pathway to Reduce Postsynaptic Density 95 Protein Levels in Young Mice.
作者信息
Lu Han, Liufu Ning, Dong Yuanlin, Xu Guanghong, Zhang Yiying, Shu Liqi, Soriano Sulpicio G, Zheng Hui, Yu Buwei, Xie Zhongcong
机构信息
From the Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (H.L., B.Y.); Department of Anesthesia, Critical Care and Medicine (H.L., N.L., Y.D., G.X., Y.Z., L.S., Z.X.) and Massachusetts General Hospital Biostatistics Center (H.Z.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China (N.L.); First Affiliated Hospital, Anhui Medical University, Hefei, China (G.X.); School of Medicine and Health Sciences, George Washington University, Washington, D.C. (L.S.); and Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts (S.G.S.).
出版信息
Anesthesiology. 2017 Dec;127(6):961-975. doi: 10.1097/ALN.0000000000001889.
BACKGROUND
Children with multiple exposures to anesthesia and surgery may have an increased risk of developing cognitive impairment. Sevoflurane, a commonly used anesthetic in children, has been reported to decrease levels of postsynaptic density 95 protein. However, the upstream mechanisms and downstream consequences of the sevoflurane-induced reduction in postsynaptic density 95 protein levels remains largely unknown. We therefore set out to assess whether sevoflurane acts on ubiquitination-proteasome pathway to facilitate postsynaptic density 95 protein degradation.
METHODS
Six-day-old wild-type mice received anesthesia with 3% sevoflurane 2 h daily for 3 days starting on postnatal day 6. We determined the effects of the sevoflurane anesthesia on mRNA, protein and ubiquitinated levels of postsynaptic density 95 protein in neurons, and synaptosomes and hippocampus of young mice. Cognitive function in the mice was determined at postnatal day 31 by using a Morris water maze. Proteasome inhibitor MG132 and E3 ligase mouse double mutant 2 homolog inhibitor Nutlin-3 were used for the interaction studies.
RESULTS
The sevoflurane anesthesia decreased protein, but not mRNA, levels of postsynaptic density 95, and reduced ubiquitinated postsynaptic density 95 protein levels in neurons, synaptosomes, and hippocampus of young mice. Both MG132 and Nutlin-3 blocked these sevoflurane-induced effects. Sevoflurane promoted the interaction of mouse double mutant 2 homolog and postsynaptic density 95 protein in neurons. Finally, MG132 and Nutlin-3 ameliorated the sevoflurane-induced cognitive impairment in the mice.
CONCLUSIONS
These data suggest that sevoflurane acts on the ubiquitination-proteasome pathway to facilitate postsynaptic density 95 protein degradation, which then decreases postsynaptic density 95 protein levels, leading to cognitive impairment in young mice. These studies would further promote the mechanistic investigation of anesthesia neurotoxicity in the developing brain.
背景
多次接受麻醉和手术的儿童发生认知障碍的风险可能会增加。七氟醚是儿童常用的一种麻醉剂，据报道它会降低突触后致密蛋白95的水平。然而，七氟醚诱导突触后致密蛋白95水平降低的上游机制和下游后果在很大程度上仍不清楚。因此，我们着手评估七氟醚是否作用于泛素化-蛋白酶体途径以促进突触后致密蛋白95的降解。
方法
6日龄野生型小鼠从出生后第6天开始，每天用3%七氟醚麻醉2小时，持续3天。我们测定了七氟醚麻醉对幼鼠神经元、突触体和海马中突触后致密蛋白95的mRNA、蛋白质和泛素化水平的影响。在出生后第31天，通过莫里斯水迷宫测定小鼠的认知功能。使用蛋白酶体抑制剂MG132和E3连接酶小鼠双突变2同源物抑制剂Nutlin-3进行相互作用研究。
结果
七氟醚麻醉降低了幼鼠神经元、突触体和海马中突触后致密蛋白95的蛋白质水平，但不影响其mRNA水平，并降低了泛素化的突触后致密蛋白95的水平。MG132和Nutlin-3均阻断了这些七氟醚诱导的效应。七氟醚促进了小鼠双突变2同源物与神经元中突触后致密蛋白95的相互作用。最后，MG132和Nutlin-3改善了七氟醚诱导的小鼠认知障碍。
结论
这些数据表明，七氟醚作用于泛素化-蛋白酶体途径以促进突触后致密蛋白95的降解，进而降低突触后致密蛋白95的水平，导致幼鼠认知障碍。这些研究将进一步推动对发育中大脑麻醉神经毒性机制的研究。
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