Wu Ya, Zheng Minqian, Wang Siqing, Song Changzhi, Wang Chuanbin, Xiao Yueping, Xu Lei, Xu Xiaozu
Department of Orthopaedics, The First People's Hospital of Yancheng, Yancheng, 224006, Jiangsu, People's Republic of China.
J Mol Histol. 2014 Oct;45(5):541-53. doi: 10.1007/s10735-014-9575-2. Epub 2014 May 7.
TNF receptor associated factor 3 (TRAF3), a member of the TRAF family of intracellular signaling proteins, can directly influence the phosphorylation status and activation of c-Jun N-terminal kinase, participating in CD40-induced apoptosis in carcinoma. However, its expression profile and function are still unclear in spinal cord injury (SCI). In this study, we performed an acute spinal cord contusion injury model in adult rats and detected the dynamic change patterns of TRAF3 expression in spinal cord. Western blot and immunohistochemistry revealed a striking upregulation of TRAF3 after SCI. Double immunofluorescence staining prompted that TRAF3 immunoreactivity was found in neurons rather than astrocytes. Moreover, co-localization of TRAF3/active caspase-3 was detected in neuronal nuclei. To further investigate the function of TRAF3, a neuronal cell line PC12 was employed to establish an apoptosis model in vitro. We analyzed the association of TRAF3 with active caspase-3 on PC12 cells by western blot and immunofluorescent labeling, which was parallel with the data in vivo. Additionally, knocking TRAF3 down with siRNA demonstrated the probable pro-apoptotic role of TRAF3 in the process of neuronal apoptosis. To summarize, we firstly uncover the temporal and spatial expression changes of TRAF3 in SCI. Our data suggest that TRAF3 might be implicated in central nervous system pathophysiology after SCI.
肿瘤坏死因子受体相关因子3（TRAF3）是细胞内信号蛋白TRAF家族的成员，可直接影响c-Jun氨基末端激酶的磷酸化状态和激活，参与CD40诱导的癌细胞凋亡。然而，其在脊髓损伤（SCI）中的表达谱和功能仍不清楚。在本研究中，我们在成年大鼠中建立了急性脊髓挫伤损伤模型，并检测了脊髓中TRAF3表达的动态变化模式。蛋白质免疫印迹法和免疫组织化学法显示，脊髓损伤后TRAF3显著上调。双重免疫荧光染色表明，TRAF3免疫反应性存在于神经元而非星形胶质细胞中。此外，在神经元细胞核中检测到TRAF3与活化的半胱天冬酶-3共定位。为了进一步研究TRAF3的功能，我们使用神经母细胞瘤细胞系PC12在体外建立了凋亡模型。我们通过蛋白质免疫印迹法和免疫荧光标记分析了TRAF3与PC12细胞上活化的半胱天冬酶-3的关联，这与体内数据一致。此外，用小干扰RNA敲低TRAF3证明了TRAF3在神经元凋亡过程中可能具有促凋亡作用。总之，我们首次揭示了脊髓损伤中TRAF3的时空表达变化。我们的数据表明，TRAF3可能与脊髓损伤后中枢神经系统的病理生理过程有关。
