Höllerhage Matthias, Duan Linghan, Chua Oscar Wing Ho, Moebius Claudia, Bothe Svenja H, Losse Kristina, Kotzur Rebecca, Lau Kristina, Hopfner Franziska, Richter Franziska, Wahl-Schott Christian, Bickle Marc, Höglinger Günter U
Department of Neurology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Center for Systems Neuroscience, Hannover, Germany.
Transl Neurodegener. 2025 Jun 3;14(1):27. doi: 10.1186/s40035-025-00486-5.
Alpha-synuclein (αSyn) is a major player in the pathophysiology of synucleinopathies, which include Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. To date, there is no disease-modifying therapy available for these synucleinopathies. Furthermore, the intracellular mechanisms by which αSyn confers toxicity are not yet fully understood. Therefore, it is of utmost importance to investigate the pathophysiology of αSyn-induced toxicity in order to identify novel molecular targets for the development of disease-modifying therapies.
We performed the first genome-wide siRNA modifier screening in a human postmitotic neuronal cell model using αSyn-induced toxicity as a read-out. In a multi-step approach, we identified several genes, whose knockdown protected against αSyn-induced toxicity. The main hit was further validated by different methods, including immunofluorescence microscopy, qPCR, and Western blot. Furthermore, the main finding was confirmed in mouse primary neurons.
The highest protection was achieved by knockdown of SNX5, which encodes the sorting nexin 5 (SNX5) protein, a component of the retromer complex. The protective efficacy of SNX5 knockdown was confirmed with an independent siRNA system. The protective effect of SNX5 knockdown was further confirmed in primary neurons from transgenic mice, where the knockdown of SNX5 led to amelioration of decrease in synchrony that was observed in untreated and control-siRNA-treated cells. SNX5 protein is a component of the SNX-BAR (Bin/Amphiphysin/Rvs) heterodimer, which is part of the retromer complex. Extracellular αSyn and overexpression of intracellular αSyn led to fragmentation of the trans-Golgi network, which was prevented by SNX5 knockdown that led to confinement of αSyn in early endosomes.
In summary, our data suggest that SNX5 plays an important role in the trafficking and toxicity of αSyn. Therefore, SNX5 appears to be a target of therapeutic intervention for synucleinopathies.
α-突触核蛋白（αSyn）是突触核蛋白病病理生理学中的主要参与者，突触核蛋白病包括帕金森病、路易体痴呆和多系统萎缩。迄今为止，尚无针对这些突触核蛋白病的疾病修饰疗法。此外，αSyn产生毒性的细胞内机制尚未完全了解。因此，研究αSyn诱导毒性的病理生理学对于确定疾病修饰疗法开发的新分子靶点至关重要。
我们在人有丝分裂后神经元细胞模型中进行了首次全基因组siRNA修饰筛选，以αSyn诱导的毒性作为读出指标。通过多步骤方法，我们鉴定了几个基因，其敲低可预防αSyn诱导的毒性。主要发现通过不同方法进一步验证，包括免疫荧光显微镜、qPCR和蛋白质印迹法。此外，在小鼠原代神经元中证实了主要发现。
通过敲低编码分选连接蛋白5（SNX5）的SNX5实现了最高保护，SNX5是逆转录复合物的一个组成部分。使用独立的siRNA系统证实了SNX5敲低的保护效果。在转基因小鼠的原代神经元中进一步证实了SNX5敲低的保护作用，其中SNX5的敲低导致在未处理和对照siRNA处理的细胞中观察到的同步性降低得到改善。SNX5蛋白是SNX-BAR（Bin/Amphiphysin/Rvs）异二聚体的一个组成部分，而SNX-BAR异二聚体是逆转录复合物的一部分。细胞外αSyn和细胞内αSyn的过表达导致反式高尔基体网络碎片化，而SNX5敲低可防止这种碎片化，SNX5敲低导致αSyn局限于早期内体。
总之，我们的数据表明SNX5在αSyn的运输和毒性中起重要作用。因此，SNX5似乎是突触核蛋白病治疗干预的一个靶点。
