Yang Xiaoxia, Cheng Jianhua, Gao Yubo, Ding Juan, Ni Xinli
Department of Anaesthesiology, General Hospital of Ningxia Medical University, Yinchuan 750004, China.
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan 750004, China.
Neuroscience. 2017 Mar 27;346:74-80. doi: 10.1016/j.neuroscience.2017.01.010. Epub 2017 Jan 17.
In adult stroke models, the neuroprotective protein, Iduna, inhibits poly (ADP-ribose) polymerase-1 (PARP-1)-dependent cell death by decreasing apoptosis-inducing factor (AIF) nuclear translocation. Because the PARP1-dependent pathway and Iduna, which promotes AIF degradation, contribute to hypoxic-ischemic (HI) brain damage in the immature brain, we examined the relationship between Iduna expression and AIF nuclear translocation in the cerebral cortex of postnatal day 7 rats after HI. Ninety rats were divided into three groups: sham, 1-h hypoxia and 2-h hypoxia. The HI insult was induced by permanent ligation of the left common carotid artery plus 1 or 2h of hypoxia. Brain damage pathological features were evaluated by hematoxylin and eosin staining, Nissl staining, transmission electron microscopy, TUNEL staining and immunofluorescence. Immunohistochemistry and western blot analysis were used to assess protein expression and ubiquitination status of AIF. The interaction between Iduna and AIF was tested by co-immunoprecipitation. Learning and memory were analyzed by the Morris water maze test. Compared with sham animals, the number of surviving neurons in the cerebral cortex decreased, and cell damage and DNA breakage were severe in rats with HI, with worse damage in the 2-h group. Iduna expression significantly decreased, whereas nuclear AIF expression increased. Furthermore, Iduna downregulation negatively correlated with nuclear AIF abundance in the 2-h HI group (r=-0.950; P<0.0001). Additionally, learning and memory ability decreased with hypoxic time. These results suggest that AIF nuclear translocation and neuronal cell death are associated with Iduna loss after severe HI in the immature brain.
在成年中风模型中，神经保护蛋白Iduna通过减少凋亡诱导因子（AIF）的核转位来抑制聚（ADP - 核糖）聚合酶 - 1（PARP - 1）依赖性细胞死亡。由于PARP1依赖性途径以及促进AIF降解的Iduna会导致未成熟脑的缺氧缺血（HI）性脑损伤，我们研究了出生后第7天的大鼠在HI后大脑皮层中Iduna表达与AIF核转位之间的关系。将90只大鼠分为三组：假手术组、1小时缺氧组和2小时缺氧组。通过永久性结扎左颈总动脉加1或2小时缺氧诱导HI损伤。通过苏木精和伊红染色、尼氏染色、透射电子显微镜、TUNEL染色和免疫荧光评估脑损伤的病理特征。采用免疫组织化学和蛋白质印迹分析评估AIF的蛋白表达和泛素化状态。通过免疫共沉淀检测Iduna与AIF之间的相互作用。通过莫里斯水迷宫试验分析学习和记忆能力。与假手术动物相比，HI大鼠大脑皮层中存活神经元数量减少，细胞损伤和DNA断裂严重，2小时组损伤更严重。Iduna表达显著降低，而核AIF表达增加。此外，在2小时HI组中Iduna下调与核AIF丰度呈负相关（r = -0.950；P < 0.0001）。此外，学习和记忆能力随缺氧时间下降。这些结果表明，在未成熟脑严重HI后，AIF核转位和神经元细胞死亡与Iduna缺失有关。
