Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder characterized pathologically by motor neuron degeneration and associated with aggregation of RNA-binding proteins. TATA-binding protein-associated factor 15 (TAF15) accumulates as cytoplasmic aggregates in neuronal cells, and clearance of these aggregates is considered a potential therapeutic strategy for ALS. However, the exact pathogenic mechanism of TAF15-induced neurotoxicity remains to be elucidated. Glycogen synthase kinase-3 (GSK-3) plays a critical role in the protection of ALS pathology. In the present study, we use a transgenic fly model over-expressing human TAF15 to study the protective effects of Shaggy/GSK3β on TAF15-induced neuronal toxicity in Drosophila brain. Transgenic flies were examined for locomotor activity and lithium treatment. The expression level and solubility of TAF15 were assessed with western blotting, whereas immunohistochemistry was used to assess TAF15 aggregation in Drosophila brain. We have revealed that Shaggy/GSK3β was abnormally activated in neurons of TAF15-expressing flies and its inhibition can suppress the defective phenotypes, thereby preventing retinal degeneration and locomotive activity caused by TAF15. We have also found that Shaggy/GSK3β inhibition in neuronal cells leads to a reduction in TAF15 levels. Indeed, the F-box proteins Slimb and archipelago genetically interact with TAF15 and control TAF15 protein level in Drosophila. Importantly, SCF^slimb is a critical regulator for Shaggy/GSK3β-mediated suppression of TAF15-induced toxicity in Drosophila. The present study has provided an in vivo evidence supporting the molecular mechanism of GSK3β inhibition for protection against TAF15-linked proteinopathies.

中文翻译：

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SCF-Slimb 对于糖原合酶激酶-3β 介导的 TAF15 诱导的果蝇神经毒性抑制至关重要

肌萎缩侧索硬化 (ALS) 是一种严重的神经退行性疾病，其病理特征为运动神经元变性并与 RNA 结合蛋白的聚集相关。TATA 结合蛋白相关因子 15 (TAF15) 在神经元细胞中作为细胞质聚集体积累，清除这些聚集体被认为是 ALS 的潜在治疗策略。然而，TAF15 诱导的神经毒性的确切致病机制仍有待阐明。糖原合酶激酶 3 (GSK-3) 在保护 ALS 病理方面起着关键作用。在本研究中，我们使用过表达人类 TAF15 的转基因果蝇模型来研究 Shaggy/GSK3β 对 TAF15 诱导的果蝇神经元毒性的保护作用脑。检查转基因果蝇的运动活性和锂处理。TAF15 的表达水平和溶解度用蛋白质印迹法评估，而免疫组织化学用于评估 TAF15 在果蝇脑中的聚集。我们发现 Shaggy/GSK3β 在表达 TAF15 的果蝇的神经元中被异常激活，其抑制作用可以抑制缺陷表型，从而防止 TAF15 引起的视网膜变性和运动活动。我们还发现神经元细胞中的 Shaggy/GSK3β 抑制导致 TAF15 水平降低。事实上，F-box 蛋白 Slimb 和 Archipelago 在基因上与 TAF15 相互作用并控制果蝇中的TAF15 蛋白水平。重要的是，SCF^苗条是果蝇中Shaggy/GSK3β 介导的 TAF15 诱导毒性抑制的关键调节剂。本研究提供了体内证据，支持 GSK3β 抑制的分子机制，以防止与 TAF15 相关的蛋白病。