Oyama Soho, Zhang Hengsen, Ferdous Rafia, Tomochika Yuna, Chen Bin, Jiang Shuyun, Islam Md Shoriful, Hasan Md Mahmudul, Zhai Qing, Waliullah A S M, Ping Yashuang, Yan Jing, Mimi Mst Afsana, Zhang Chi, Aramaki Shuhei, Takanashi Yusuke, Kahyo Tomoaki, Hashizume Yoshio, Kaneda Daita, Setou Mitsutoshi
Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Chuo-ku, Hamamatsu 431-3192, Shizuoka, Japan.
Department of Neurosurgery, The Affiliated Hospital of Jiangnan University, Wuxi 214000, China.
Neurol Int. 2024 Oct 22;16(6):1175-1188. doi: 10.3390/neurolint16060089.
BACKGROUND/OBJECTIVES: UBL3 (Ubiquitin-like 3) is a protein that plays a crucial role in post-translational modifications, particularly in regulating protein transport within small extracellular vesicles. While previous research has predominantly focused on its interactions with α-synuclein, this study investigates UBL3's role in Huntington's disease (HD). HD is characterized by movement disorders and cognitive impairments, with its pathogenesis linked to toxic, polyglutamine (polyQ)-expanded mutant huntingtin fragments (mHTT). However, the mechanisms underlying the interaction between UBL3 and mHTT remain poorly understood.
To elucidate this relationship, we performed hematoxylin and eosin (HE) staining and immunohistochemistry (IHC) on postmortem brain tissue from HD patients. Gaussia princeps-based split-luciferase complementation assay and co-immunoprecipitation were employed to confirm the interaction between UBL3 and mHTT. Additionally, we conducted a HiBiT lytic detection assay to assess the influence of UBL3 on the intracellular sorting of mHTT. Finally, immunocytochemical staining was utilized to validate the colocalization and distribution of these proteins.
Our findings revealed UBL3-positive inclusions in the cytoplasm and nuclei of neurons throughout the striatum of HD patients. We discovered that UBL3 colocalizes and interacts with mHTT and modulates its intracellular sorting.
These results suggest that UBL3 may play a significant role in the interaction and sorting of mHTT, contributing to the understanding of its potential implications in the pathophysiology of Huntington's disease.
背景/目的：UBL3（泛素样蛋白3）是一种在翻译后修饰中起关键作用的蛋白质，尤其在调节小细胞外囊泡内的蛋白质运输方面。虽然先前的研究主要集中在它与α-突触核蛋白的相互作用上，但本研究调查了UBL3在亨廷顿舞蹈病（HD）中的作用。HD的特征是运动障碍和认知障碍，其发病机制与有毒的、多聚谷氨酰胺（polyQ）扩展的突变亨廷顿蛋白片段（mHTT）有关。然而，UBL3与mHTT之间相互作用的潜在机制仍知之甚少。
为了阐明这种关系，我们对HD患者的死后脑组织进行了苏木精和伊红（HE）染色及免疫组织化学（IHC）。采用基于高斯王子荧光素酶互补分析和免疫共沉淀来证实UBL3与mHTT之间的相互作用。此外，我们进行了HiBiT裂解检测分析，以评估UBL3对mHTT细胞内分选的影响。最后，利用免疫细胞化学染色来验证这些蛋白质的共定位和分布。
我们的研究结果显示，在HD患者纹状体的整个神经元细胞质和细胞核中存在UBL3阳性包涵体。我们发现UBL3与mHTT共定位并相互作用，并调节其细胞内分选。
这些结果表明，UBL3可能在mHTT的相互作用和分选中发挥重要作用，有助于理解其在亨廷顿舞蹈病病理生理学中的潜在意义。
