Department of Neurosurgery, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan.
Department of Neurosurgery, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan.
Exp Neurol. 2021 May;339:113642. doi: 10.1016/j.expneurol.2021.113642. Epub 2021 Feb 15.
Hematopoietic cell-specific protein 1 associated protein X-1 (HAX-1) is a novel mitochondrial protein that regulates oxidative stress-induced apoptosis. However, the roles of HAX-1 in ischemic neuronal injury have not been thoroughly elucidated. In this study, the expression and roles of HAX-1 after ischemic stress were investigated using in vivo and in vitro models. The effect of oxidative stress on the regulation of HAX-1 was examined using knockout mice lacking nicotinamide-adenine dinucleotide phosphate oxidase 2 (NOX2), which is a major source of reactive oxygen species (ROS) after cerebral ischemia. Male C57BL/6 J mice were subjected to transient forebrain ischemia induced by 22-min occlusion of the bilateral common carotid arteries, and striatum samples were analyzed. For in vitro ischemic experiments, oxygen and glucose deprivation (OGD) in a rat pheochromocytoma cell line was utilized. Western blotting and immunofluorescence analysis revealed HAX-1 expression in neuronal mitochondria, which was significantly decreased after ischemia in vivo and in vitro. In NOX2 knockout mice, ischemia-induced decrease in HAX-1 expression and ischemic neuronal injury was significantly alleviated compared to those in wild-type mice. Inhibition of HAX-1 using small interfering RNA significantly increased injury in cultured cells after OGD. These findings suggest that HAX-1 has a neuroprotective effect against ischemic neuronal injury, and downregulation of HAX-1 by NOX2-produced ROS induces apoptosis after cerebral ischemia.
造血细胞特异性蛋白 1 相关蛋白 X-1（HAX-1）是一种新型的线粒体蛋白，可调节氧化应激诱导的细胞凋亡。然而，HAX-1 在缺血性神经元损伤中的作用尚未得到充分阐明。在这项研究中，使用体内和体外模型研究了缺血应激后 HAX-1 的表达和作用。使用缺乏烟酰胺腺嘌呤二核苷酸磷酸氧化酶 2（NOX2）的敲除小鼠（NOX2 是脑缺血后活性氧（ROS）的主要来源），研究了氧化应激对 HAX-1 调节的影响。雄性 C57BL/6J 小鼠接受双侧颈总动脉闭塞 22 分钟诱导的短暂前脑缺血，分析纹状体样本。对于体外缺血实验，使用大鼠嗜铬细胞瘤细胞系进行氧葡萄糖剥夺（OGD）。Western blot 和免疫荧光分析显示 HAX-1 在神经元线粒体中的表达，在体内和体外缺血后明显减少。与野生型小鼠相比，NOX2 敲除小鼠的缺血诱导 HAX-1 表达减少和缺血性神经元损伤明显减轻。使用小干扰 RNA 抑制 HAX-1 后，OGD 后培养细胞的损伤明显增加。这些发现表明，HAX-1 对缺血性神经元损伤具有神经保护作用，NOX2 产生的 ROS 下调 HAX-1 可诱导脑缺血后的细胞凋亡。
