Krzystek Thomas J, Rathnayake Rasika, Zeng Jia, Huang Jing, Iacobucci Gary, Yu Michael C, Gunawardena Shermali
Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA.
Neuroscience Program, The State University of New York at Buffalo, Buffalo, NY, USA.
Cell Death Dis. 2025 Apr 22;16(1):328. doi: 10.1038/s41419-025-07524-0.
Huntington's disease (HD) is a devastating neurodegenerative disorder that manifests from an N-terminal polyQ-expansion (>35) in the Huntingtin (HTT) gene leading to axonal degeneration and significant neuronal death. Despite evidence for a scaffolding role for HTT in membrane-related processes such as endocytosis, vesicle transport, and vesicle fusion, it remains unclear how polyQ-expansion alters membrane binding during these processes. Using quantitative Mass Spectrometry-based proteomics on HTT-containing light vesicle membranes isolated from healthy and HD iPSC-derived neurons, we found significant changes in the proteome and kinome of signal transduction, neuronal translation, trafficking, and axon guidance-related processes. Through a combination of in vitro kinase assays, Drosophila genetics, and pharmacological inhibitors, we identified that GSK3β and ERK1 phosphorylate HTT and that these events play distinct and opposing roles during HD with inhibition of GSK3β decreasing polyQ-mediated axonal transport defects and neuronal cell death, while inhibition of ERK enhancing these phenotypes. Together, this work proposes two novel pathways in which GSK3β phosphorylation events exacerbate and ERK phosphorylation events mitigate HD-dependent neuronal dysfunction highlighting a highly druggable pathway for targeted therapeutics using already available small molecules.
亨廷顿舞蹈症（HD）是一种毁灭性的神经退行性疾病，由亨廷顿蛋白（HTT）基因中N端多聚谷氨酰胺扩展（>35）引起，导致轴突退化和大量神经元死亡。尽管有证据表明HTT在诸如内吞作用、囊泡运输和囊泡融合等膜相关过程中起支架作用，但尚不清楚多聚谷氨酰胺扩展如何在这些过程中改变膜结合。通过对从健康和HD诱导多能干细胞衍生的神经元中分离出的含HTT的轻型囊泡膜进行基于定量质谱的蛋白质组学研究，我们发现信号转导、神经元翻译、运输和轴突导向相关过程的蛋白质组和激酶组有显著变化。通过体外激酶测定、果蝇遗传学和药理抑制剂的组合，我们确定糖原合酶激酶3β（GSK3β）和细胞外信号调节激酶1（ERK1）使HTT磷酸化，并且这些事件在HD过程中发挥不同且相反的作用，抑制GSK3β可减少多聚谷氨酰胺介导的轴突运输缺陷和神经元细胞死亡，而抑制ERK则会加剧这些表型。总之，这项工作提出了两条新途径，其中GSK3β磷酸化事件加剧HD依赖性神经元功能障碍，而ERK磷酸化事件减轻该障碍，突出了一条使用现有小分子进行靶向治疗的高度可药物化途径。
