Cheng Xi, Tang Yu, Vidyadhara D J, Li Ben-Zheng, Zimmerman Michael, Pak Alexandr, Nareddula Sanghamitra, Edens Paige Alyssa, Chandra Sreeganga S, Chubykin Alexander A
Department of Biological Sciences, Purdue Institute for Integrative Neuroscience, Purdue Autism Research Center, Purdue University, West Lafayette, IN 47907, USA.
Department of Neurology, Yale University, CT, USA.
iScience. 2023 Sep 6;26(10):107842. doi: 10.1016/j.isci.2023.107842. eCollection 2023 Oct 20.
Auxilin (DNAJC6/PARK19), an endocytic co-chaperone, is essential for maintaining homeostasis in the readily releasable pool (RRP) by aiding clathrin-mediated uncoating of synaptic vesicles. Its loss-of-function mutations, observed in familial Parkinson's disease (PD), lead to basal ganglia motor deficits and cortical dysfunction. We discovered that auxilin-knockout (Aux-KO) mice exhibited impaired pre-synaptic plasticity in layer 4 to layer 2/3 pyramidal cell synapses in the primary visual cortex (V1), including reduced short-term facilitation and depression. Computational modeling revealed increased RRP refilling during short repetitive stimulation, which diminished during prolonged stimulation. Silicon probe recordings in V1 of Aux-KO mice demonstrated disrupted visual cortical circuit responses, including reduced orientation selectivity, compromised visual mismatch negativity, and shorter visual familiarity-evoked theta oscillations. Pupillometry analysis revealed an impaired optokinetic response. Auxilin-dependent pre-synaptic endocytosis dysfunction was associated with deficits in pre-synaptic plasticity, visual cortical functions, and eye movement prodromally or at the early stage of motor symptoms.
辅助蛋白(DNAJC6/PARK19)是一种内吞作用的共伴侣蛋白,通过协助网格蛋白介导的突触小泡脱衣被,对于维持即时可释放池(RRP)的稳态至关重要。在家族性帕金森病(PD)中观察到的其功能丧失突变会导致基底神经节运动缺陷和皮质功能障碍。我们发现,辅助蛋白敲除(Aux-KO)小鼠在初级视觉皮层(V1)第4层到第2/3层锥体细胞突触处表现出突触前可塑性受损,包括短期易化和抑制作用减弱。计算模型显示,在短时间重复刺激期间RRP再填充增加,而在长时间刺激期间则减少。对Aux-KO小鼠V1区的硅探针记录显示视觉皮层回路反应中断,包括方向选择性降低、视觉失配负波受损以及视觉熟悉诱发的θ振荡缩短。瞳孔测量分析显示视动反应受损。辅助蛋白依赖性突触前内吞功能障碍与突触前可塑性、视觉皮层功能以及运动症状前驱期或早期的眼动缺陷有关。