Department of Orthopedics, The First People's Hospital of Pingdingshan, Pingdingshan, China.
Department of Orthopedics, Henan Provincial Orthopedic Hospital, Zhengzhou, China.
Neurol Res. 2024 Nov;46(11):1008-1017. doi: 10.1080/01616412.2024.2376999. Epub 2024 Jul 15.
Ubiquitin-specific protease 7 (USP7) has been found to be associated with motor function recovery after spinal cord injury (SCI). Therefore, its role and mechanism in SCI process need further exploration.
SCI rat models were established via performing laminectomy at the T9-T11 spinal vertebrae and cutting spinal cord tissues. SCI cell models were constructed by inducing PC12 cells with lipopolysaccharide (LPS). The protein levels of USP7, nuclear respiratory factor 1 (NRF1), Krüppel-like factor 7 (KLF7) and apoptosis-related markers were detected by western blot. Cell viability and apoptosis were tested by cell counting kit-8 assay and flow cytometry. The contents of inflammatory factors were examined using ELISA. The interaction between NRF1 and USP7 or KLF7 was analyzed by co-immunoprecipitation assay, chromatin immunoprecipitation assay and dual-luciferase reporter assay, respectively.
USP7 was downregulated in SCI rat models and LPS-induced PC12 cells. Overexpressed USP7 promoted viability, while repressed apoptosis and inflammation in LPS-induced PC12 cells. USP7 could stabilize NRF1 protein expression via deubiquitination, and NRF1 knockdown reversed the protective effect of USP7 against LPS-induced PC12 cell injury. NRF1 is bound to KLF7 promoter to enhance its transcription. NRF1 overexpression inhibited LPS-induced PC12 cell inflammation and apoptosis via increasing KLF7 expression.
USP7 alleviated inflammation and apoptosis in LPS-induced PC12 cells via NRF1/KLF7 axis, indicating that targeting of USP7/NRF1/KLF7 axis might be a promising treatment strategy for SCI.
泛素特异性蛋白酶 7（USP7）已被发现与脊髓损伤（SCI）后运动功能恢复有关。因此，其在 SCI 过程中的作用和机制需要进一步探索。
通过在 T9-T11 脊髓椎骨进行椎板切除术和切割脊髓组织来建立 SCI 大鼠模型。通过用脂多糖（LPS）诱导 PC12 细胞来构建 SCI 细胞模型。通过 Western blot 检测 USP7、核呼吸因子 1（NRF1）、Krüppel 样因子 7（KLF7）和凋亡相关标志物的蛋白水平。通过细胞计数试剂盒-8 测定法和流式细胞术检测细胞活力和凋亡。通过 ELISA 检测炎症因子的含量。通过免疫共沉淀测定、染色质免疫沉淀测定和双荧光素酶报告基因测定分别分析 NRF1 与 USP7 或 KLF7 之间的相互作用。
USP7 在 SCI 大鼠模型和 LPS 诱导的 PC12 细胞中下调。过表达 USP7 可促进 LPS 诱导的 PC12 细胞活力，抑制其凋亡和炎症。USP7 通过去泛素化稳定 NRF1 蛋白表达，而 NRF1 敲低逆转了 USP7 对 LPS 诱导的 PC12 细胞损伤的保护作用。NRF1 与 KLF7 启动子结合以增强其转录。NRF1 过表达通过增加 KLF7 表达抑制 LPS 诱导的 PC12 细胞炎症和凋亡。
USP7 通过 NRF1/KLF7 轴减轻 LPS 诱导的 PC12 细胞炎症和凋亡，表明靶向 USP7/NRF1/KLF7 轴可能是治疗 SCI 的一种有前途的策略。
