ZCCHC17 modulates neuronal RNA splicing and supports cognitive resilience in Alzheimer’s disease. ZCCHC17 modulates neuronal RNA splicing and supports cognitive resilience in Alzheimer’s disease

ZCCHC17 is a zinc-finger protein previously identified as a regulator of synaptic gene expression which becomes dysfunctional in Alzheimer’s disease. Here, we further investigate the function of ZCCHC17. Co-immunoprecipitation of ZCCHC17 followed by mass spectrometry analysis in human iPSC-derived neurons reveals that ZCCHC17’s binding partners are enriched for RNA splicing proteins. ZCCHC17 knockdown results in widespread RNA splicing changes that significantly overlap with splicing changes found in AD brain tissue, with synaptic genes commonly affected. ZCCHC17 expression positively correlates with cognitive resilience in AD patients, and we uncover an APOE4-dependent negative correlation of ZCCHC17 expression with tangle burden. Furthermore, a majority of ZCCHC17 interactors also co-IP with known tau interactors, and we find significant overlap between alternatively spliced genes in ZCCHC17 knockdown and tau overexpression neurons. These results demonstrate ZCCHC17’s role in neuronal RNA processing and its interactions with pathology and cognitive resilience in AD. Overall design: 6 negative control siRNA-treated iPSC-derived neurons (siNC); 6 ZCCHC17 siRNA-treated iPSC-derived neurons (siZCC)

ZCCHC17是一种锌指蛋白（zinc-finger protein），此前被鉴定为突触基因表达的调控因子，在阿尔茨海默病（Alzheimer’s disease，AD）中发生功能异常。本研究进一步探究了ZCCHC17的生物学功能。通过对人诱导多能干细胞（induced pluripotent stem cell，iPSC）分化而来的神经元进行ZCCHC17免疫共沉淀（co-immunoprecipitation）结合质谱分析，结果显示ZCCHC17的结合蛋白显著富集于RNA剪接（RNA splicing）相关蛋白。ZCCHC17敲低会引发广泛的RNA剪接异常，该异常与阿尔茨海默病脑组织中观察到的剪接变化显著重合，且突触基因多受其影响。ZCCHC17的表达水平与阿尔茨海默病患者的认知弹性呈正相关；本研究还发现，ZCCHC17表达与神经原纤维缠结负荷（tangle burden）之间存在依赖于载脂蛋白E4（apolipoprotein E4，APOE4）的负相关关系。此外，绝大多数与ZCCHC17存在相互作用的蛋白同时也可与已知的tau蛋白相互作用蛋白发生免疫共沉淀；本研究还发现，ZCCHC17敲低组神经元与tau蛋白过表达组神经元的可变剪接基因存在显著重合。上述结果证实了ZCCHC17在神经元RNA加工过程中的功能，以及其与阿尔茨海默病病理进程和认知弹性的关联。
实验设计：6例经阴性对照小干扰RNA（small interfering RNA，siRNA）处理的人诱导多能干细胞分化神经元（siNC组）；6例经ZCCHC17小干扰RNA处理的人诱导多能干细胞分化神经元（siZCC组）