Department of Rehabilitation, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
Department of Emergency, First Xiangya Hospital, Central South University, Changsha, Hunan, China.
J Mol Histol. 2020 Jun;51(3):307-315. doi: 10.1007/s10735-020-09881-w. Epub 2020 May 25.
Cerebral ischemia-reperfusion injury is pivotal in the development of multiple-subcellular organelle and tissue injury after acute ischemic stroke. Recently, the Golgi apparatus (GA) has been shown to be a key subcellular organelle that plays an important role in neuroprotection against oxygen-glucose deprivation/reperfusion (OGD/R) injury. PAQR3, a scaffold protein exclusively localized in the GA, was originally discovered as a potential tumor suppressor protein. PAQR3 acts as a spatial regulator of Raf-1 that binds Raf-1 and sequesters it to the GA, where it negatively modulates the Ras/Raf/MEK/ERK signaling pathway in tumor models. Studies suggest that suppression of the ERK pathway can alleviate OGD/R-induced cell apoptosis. However, whether PAQR3 has potential effects on ischemic stroke and the underlying mechanism(s) remain unexplored. The current study is the first to show that PAQR3 was significantly downregulated in mouse neuroblastoma (N2A) cells upon OGD/R exposure, both at the mRNA and protein levels. Compared to that in controls, the mRNA level of PAQR3 began to decline at 0 h (0 h) after reperfusion, while the protein level began to decline at 4 h. Furthermore, overexpression of PAQR3 reduced OGD/R-induced apoptosis. The mRNA and protein levels of total ERK1 and ERK2 were unaltered, while activated p-ERK1 and p-ERK2 were decreased in N2A cells transfected with a PAQR3 expression vector after OGD for 4 h plus 24 h of reperfusion. Collectively, these data indicated that increased PAQR3 expression protected against OGD/R-induced apoptosis possibly by inhibiting the ERK signaling pathway. Therefore, PAQR3 might be a new attractive target in the treatment of OGD/R insult, and the underlying mechanism will pave the way for its potential experimental and clinical application.
脑缺血再灌注损伤是急性缺血性脑卒中后多细胞亚细胞器和组织损伤发展的关键。最近，高尔基器（GA）被证明是一个关键的细胞亚细胞器，在对抗氧葡萄糖剥夺/再灌注（OGD/R）损伤的神经保护中发挥重要作用。PAQR3 是一种专门定位于 GA 的支架蛋白，最初被发现是一种潜在的肿瘤抑制蛋白。PAQR3 作为 Raf-1 的空间调节剂发挥作用，它与 Raf-1 结合并将其隔离到 GA 中，在那里它负向调节肿瘤模型中的 Ras/Raf/MEK/ERK 信号通路。研究表明，抑制 ERK 通路可以减轻 OGD/R 诱导的细胞凋亡。然而，PAQR3 是否对缺血性中风具有潜在影响以及潜在机制仍未被探索。本研究首次表明，在 OGD/R 暴露后，小鼠神经母细胞瘤（N2A）细胞中的 PAQR3 表达在 mRNA 和蛋白水平均显著下调。与对照组相比，PAQR3 的 mRNA 水平在再灌注 0 小时（0 h）开始下降，而蛋白水平则在 4 小时开始下降。此外，过表达 PAQR3 可减少 OGD/R 诱导的细胞凋亡。在 OGD 4 小时加再灌注 24 小时后，转染 PAQR3 表达载体的 N2A 细胞中总 ERK1 和 ERK2 的 mRNA 和蛋白水平不变，而激活的 p-ERK1 和 p-ERK2 减少。综上所述，这些数据表明，增加 PAQR3 的表达可能通过抑制 ERK 信号通路来保护细胞免受 OGD/R 诱导的凋亡。因此，PAQR3 可能是治疗 OGD/R 损伤的一个新的有吸引力的靶点，其潜在机制将为其潜在的实验和临床应用铺平道路。
