Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China..
Exp Neurol. 2018 Apr;302:22-33. doi: 10.1016/j.expneurol.2017.12.015. Epub 2017 Dec 29.
The endoplasmic reticulum stress-related factor CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) aggravates early brain injury (EBI) in rats after subarachnoid hemorrhage (SAH). Our research aims to investigate the role of CHOP-mediated iron metabolism in EBI after SAH and the underlying mechanism. Male Sprague-Dawley rats were used to establish SAH models. Tunicamycin (Tm) was employed to excite CHOP expression, and two CHOP small interfering RNAs (siRNAs) were used to inhibit CHOP expression. Neurological scores, brain water content, and blood-brain barrier (BBB) permeability were evaluated at 24h after SAH. Western blotting and immunofluorescence were implemented for the quantification and localization of GRP78 (glucoseregulated protein78), CHOP, C/EBPα (CCAAT/enhancer binding proteinα) and hepcidin. Apoptotic cells were detected by TUNEL staining, and the brain iron content was measured via Perls' staining. The expression of CHOP and hepcidin increased and the expression of C/EBPα decreased after SAH. Knockdown of CHOP decreased the brain water content, reduced Evans blue extravasation, and improved neurological functions. CHOP significantly increased hepcidin levels and significantly decreased C/EBPα levels after SAH. Hepcidin is expressed in the nuclei of neurons and is widely co-localized with TUNEL-positive cells both in the hippocampus and cortex. Along with increased hepcidin expression, the iron content in brain tissue and the apoptosis rate were increased. Thus, CHOP promotes hepcidin expression by regulating C/EBPα activity, which increases the brain iron content, induces apoptosis and is involved in the development of EBI after SAH.
内质网应激相关因子 CCAAT/增强子结合蛋白（C/EBP）同源蛋白（CHOP）加重蛛网膜下腔出血（SAH）后大鼠早期脑损伤（EBI）。我们的研究旨在探讨 CHOP 介导的铁代谢在 SAH 后 EBI 中的作用及其机制。雄性 Sprague-Dawley 大鼠用于建立 SAH 模型。使用衣霉素（Tm）激发 CHOP 表达，并使用两种 CHOP 小干扰 RNA（siRNA）抑制 CHOP 表达。在 SAH 后 24 小时评估神经功能评分、脑水含量和血脑屏障（BBB）通透性。Western blot 和免疫荧光用于定量和定位葡萄糖调节蛋白 78（glucoseregulated protein78）、CHOP、CCAAT/增强子结合蛋白α（CCAAT/enhancer binding proteinα）和铁调素。通过 TUNEL 染色检测凋亡细胞，通过 Perls'染色测量脑铁含量。SAH 后 CHOP 和铁调素表达增加，C/EBPα表达减少。敲低 CHOP 可降低脑水含量，减少 Evans 蓝渗出，并改善神经功能。CHOP 显著增加 SAH 后铁调素水平，显著降低 C/EBPα水平。铁调素在神经元核中表达，在海马和皮质中与 TUNEL 阳性细胞广泛共定位。随着铁调素表达增加，脑组织中铁含量和细胞凋亡率增加。因此，CHOP 通过调节 C/EBPα 活性促进铁调素表达，增加脑铁含量，诱导细胞凋亡，参与 SAH 后 EBI 的发生。
