Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases; National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, China.
Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, China.
Hum Mol Genet. 2022 Nov 10;31(22):3886-3896. doi: 10.1093/hmg/ddac142.
The D620N mutation in vacuolar protein sorting protein 35 (VPS35) gene has been identified to be linked to late onset familial Parkinson disease (PD). However, the pathophysiological roles of VPS35-D620N in PD remain unclear. Here, we generated the transgenic Caenorhabditis elegans overexpressing either human wild type or PD-linked mutant VPS35-D620N in neurons. C. elegans expressing VPS35-D620N, compared with non-transgenic controls, showed movement disorders and dopaminergic neuron loss. VPS35-D620N worms displayed more swimming induced paralysis but showed no defects in BSR assays, thus indicating the disruption of dopamine (DA) recycling back inside neurons. Moreover, VPS35 formed a protein interaction complex with DA transporter (DAT), RAB5, RAB11 and FAM21. In contrast, the VPS35-D620N mutant destabilized these interactions, thus disrupting DAT transport from early endosomes to recycling endosomes, and decreasing DAT at the cell surface. These effects together increased DA in synaptic clefts, and led to dopaminergic neuron degeneration and motor dysfunction. Treatment with reserpine significantly decreased the swimming induced paralysis in VPS35-D620N worms, as compared with vehicle treated VPS35-D620N worms. Our studies not only provide novel insights into the mechanisms of VPS35-D620N-induced dopaminergic neuron degeneration and motor dysfunction via disruption of DAT function and the DA signaling pathway but also indicate a potential strategy to treat VPS35-D620N-related PD and other disorders.
空泡分选蛋白 35（VPS35）基因中的 D620N 突变已被确定与晚发性家族性帕金森病（PD）有关。然而，VPS35-D620N 在 PD 中的病理生理作用仍不清楚。在这里，我们在神经元中生成了过度表达人野生型或 PD 相关突变 VPS35-D620N 的转基因秀丽隐杆线虫。与非转基因对照相比，表达 VPS35-D620N 的秀丽隐杆线虫表现出运动障碍和多巴胺能神经元丧失。VPS35-D620N 线虫表现出更多的游泳诱导瘫痪，但在 BSR 测定中没有缺陷，因此表明多巴胺（DA）的再循环回神经元内部受到破坏。此外，VPS35 与多巴胺转运体（DAT）、RAB5、RAB11 和 FAM21 形成蛋白质相互作用复合物。相比之下，VPS35-D620N 突变体破坏了这些相互作用，从而破坏了 DAT 从早期内体向再循环内体的转运，并减少了细胞表面的 DAT。这些效应共同增加了突触小泡中的 DA，并导致多巴胺能神经元退化和运动功能障碍。与用载体处理的 VPS35-D620N 线虫相比，用利血平处理显著降低了 VPS35-D620N 线虫的游泳诱导瘫痪。我们的研究不仅提供了新的见解，即通过破坏 DAT 功能和 DA 信号通路，VPS35-D620N 诱导的多巴胺能神经元退化和运动功能障碍的机制，而且还表明了一种治疗 VPS35-D620N 相关 PD 和其他疾病的潜在策略。
