Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.
Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
Mov Disord. 2021 Dec;36(12):2768-2779. doi: 10.1002/mds.28698. Epub 2021 Jun 26.
Acetylcholine-mediated transmission plays a central role in the impairment of corticostriatal synaptic activity and plasticity in multiple DYT1 mouse models. However, the nature of such alteration remains unclear.
The aim of the present work was to characterize the mechanistic basis of cholinergic dysfunction in DYT1 dystonia to identify potential targets for pharmacological intervention.
We utilized electrophysiology recordings, immunohistochemistry, enzymatic activity assays, and Western blotting techniques to analyze in detail the cholinergic machinery in the dorsal striatum of the Tor1a mouse model of DYT1 dystonia.
We found a significant increase in the vesicular acetylcholine transporter (VAChT) protein level, the protein responsible for loading acetylcholine (ACh) from the cytosol into synaptic vesicles, which indicates an altered cholinergic tone. Accordingly, in Tor1a mice we measured a robust elevation in basal ACh content coupled to a compensatory enhancement of acetylcholinesterase (AChE) enzymatic activity. Moreover, pharmacological activation of dopamine D2 receptors, which is expected to reduce ACh levels, caused an abnormal elevation in its content, as compared to controls. Patch-clamp recordings revealed a reduced effect of AChE inhibitors on cholinergic interneuron excitability, whereas muscarinic autoreceptor function was preserved. Finally, we tested the hypothesis that blockade of VAChT could restore corticostriatal long-term synaptic plasticity deficits. Vesamicol, a selective VAChT inhibitor, rescued a normal expression of synaptic plasticity.
Overall, our findings indicate that VAChT is a key player in the alterations of striatal plasticity and a novel target to normalize cholinergic dysfunction observed in DYT1 dystonia. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
乙酰胆碱介导的传递在多个 DYT1 小鼠模型中皮质纹状体突触活动和可塑性的损伤中起着核心作用。然而，这种改变的性质尚不清楚。
本工作旨在描述 DYT1 肌张力障碍中胆碱能功能障碍的机制基础，以确定潜在的药物干预靶点。
我们利用电生理学记录、免疫组织化学、酶活性测定和 Western blot 技术，详细分析了 DYT1 肌张力障碍 Tor1a 小鼠模型背侧纹状体中的胆碱能机制。
我们发现囊泡乙酰胆碱转运体（VAChT）蛋白水平显著增加，该蛋白负责将乙酰胆碱（ACh）从细胞质加载到突触小泡中，表明胆碱能张力发生改变。相应地，在 Tor1a 小鼠中，我们测量到基础 ACh 含量的显著增加，同时伴有乙酰胆碱酯酶（AChE）酶活性的代偿性增强。此外，多巴胺 D2 受体的药理学激活预计会降低 ACh 水平，但与对照组相比，其含量异常升高。膜片钳记录显示 AChE 抑制剂对胆碱能中间神经元兴奋性的作用降低，而毒蕈碱自身受体功能得到保留。最后，我们测试了阻断 VAChT 可以恢复皮质纹状体长时程突触可塑性缺陷的假设。囊泡转运蛋白选择性抑制剂，即维拉米酯，可恢复正常的突触可塑性表达。
总之，我们的研究结果表明，VAChT 是纹状体可塑性改变的关键因素，也是一种新型的靶向药物，可以纠正 DYT1 肌张力障碍中观察到的胆碱能功能障碍。
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