Department of Neurosurgery, First Affiliated Hospital of Shihezi University, Shihezi, 832000, China.
Department of Neurosurgery, The People's Hospital of Xinjiang Uygur Autonomous Region, Urumchi, 830001, China.
Neurochem Res. 2018 Jul;43(7):1383-1391. doi: 10.1007/s11064-018-2553-4. Epub 2018 May 22.
Neuritin is an extracellular glycophosphatidylinositol-linked protein that promotes neuronal survival, differentiation, function, and repair, but the exact mechanism of this neuroprotective effect remains unclear. Meanwhile, endoplasmic reticulum stress (ERS) induced apoptosis is attracting increased attention. In this work, we hypothesized that neuritin inhibited ERS to protect cortical neurons. To check this hypothesis, we exposed primary cultured cortical neurons to oxygen and glucose deprivation (OGD) for 45 min followed by reperfusion (R) to activate ERS. We then performed resuscitation for 6, 12, 24, and 48 h. ERS-related factors such as glucose-regulated protein 78 (GRP78), caspase-12 and CHOP were detected by Western blotting and quantitative real-time polymerase chain reaction assay. Apoptosis was assessed by Annexin V binding and propidium iodide staining. Ultrastructural changes of endoplasmic reticulum were observed under a transmission electron microscope. Results showed that GRP78 expression significantly increased at 12, 24, and 48 h and peaked at 24 h. Caspase-12 and CHOP expression significantly increased in a time-dependent manner at 12, 24, and 48 h. GRP78, caspase-12 and CHOP expression as well as apoptosis rate of primary cultured neurons and the ultrastructural changes of endoplasmic reticulum in the OGD/R + neuritin group significantly improved compared with the OGD/R group. In conclusion, the neuroprotection function of neuritin may be involved in ERS pathways.
神经调节素是一种细胞外糖磷脂酰肌醇连接蛋白，能促进神经元存活、分化、功能和修复，但这种神经保护作用的确切机制尚不清楚。同时，内质网应激（ERS）诱导的细胞凋亡正引起越来越多的关注。在这项工作中，我们假设神经调节素通过抑制 ERS 来保护皮质神经元。为了验证这一假设，我们将原代培养的皮质神经元暴露于氧葡萄糖剥夺（OGD）45 分钟，然后再进行复氧（R）以激活 ERS。随后进行 6、12、24 和 48 小时的复苏。通过 Western blot 和实时定量聚合酶链反应检测 ERS 相关因子，如葡萄糖调节蛋白 78（GRP78）、半胱氨酸天冬氨酸蛋白酶-12（caspase-12）和 C/EBP 同源蛋白（CHOP）。通过 Annexin V 结合和碘化丙啶染色评估细胞凋亡。用透射电子显微镜观察内质网的超微结构变化。结果显示，GRP78 表达在 12、24 和 48 小时时明显增加，在 24 小时时达到高峰。caspase-12 和 CHOP 的表达在 12、24 和 48 小时时呈时间依赖性增加。与 OGD/R 组相比，OGD/R+神经调节素组原代培养神经元的 GRP78、caspase-12 和 CHOP 表达以及细胞凋亡率和内质网的超微结构变化均明显改善。综上所述，神经调节素的神经保护功能可能涉及 ERS 途径。
