Cerebral ischemia, a common cerebrovascular disease, is characterized by functional deficits and apoptotic cell death. Autophagy, a type of programmed cell death, plays critical roles in controlling neuronal damage and metabolic homeostasis, and has been inextricably linked to cerebral ischemia. We previously identified a short peptide aptamer from collapsin response mediator protein 2 (CRMP2), designated the Ca2+ channel-binding domain 3 (CBD3) peptide, that conferred protection against excitotoxicity and traumatic brain injury. ST2-104, a nona-arginine (R9)-fused CBD3 peptide, exerted beneficial effects on neuropathic pain and was neuroprotective in a model of Alzheimer’s disease; however, the effect of ST2-104 on cerebral ischemia and its mechanism of action have not been studied. In this study, we modeled cerebral ischemia–reperfusion injury in rats with the middle cerebral artery occlusion (MCAO) as well as challenged SH-SY5Y neuroblastoma cells with glutamate to induce toxicity to interrogate the effects of ST2-104 on autophagy following ischemic/excitotoxic insults. ST2-104 reduced the infarct volume and improved the neurological score of rats subjected to MCAO. ST2-104 protected SH-SY5Y cells from death following glutamate exposure via blunting apoptosis and autophagy as well as limiting excessive calcium entry. 3-Methyladenine (3-MA), an inhibitor of autophagy, promoted the effects of ST2-104 in inhibiting apoptosis triggered by glutamate while rapamycin, an activator of autophagy, failed to do so. ST2-104 peptide reversed glutamate-induced apoptosis via inhibiting Ca2+/CaM-dependent protein kinase kinase β (CaMKKβ)-mediated autophagy, which was partly enhanced by STO-609 (an inhibitor of CaMKKβ). ST2-104 attenuated neuronal apoptosis by inhibiting autophagy through CaMKKβ/AMPK/mTOR pathway. Our results suggest that the neuroprotective effect of ST2-104 are due to actions on the crosstalk between apoptosis and autophagy via the CaMKKβ/AMPK/mTOR signaling pathway. The findings present novel insights into the potential neuroprotection of ST2-104 in cerebral ischemia.

中文翻译：

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CRMP2 衍生肽 ST2-104 (R9-CBD3) 通过 CaMKKβ/AMPK/mTOR 途径抑制自噬有助于缺血后处理诱导的脑缺血再灌注损伤的神经保护作用


脑缺血是一种常见的脑血管疾病，其特征是功能缺陷和细胞凋亡。自噬是一种程序性细胞死亡，在控制神经元损伤和代谢稳态中发挥着关键作用，并且与脑缺血有着千丝万缕的联系。我们之前从崩溃蛋白反应介导蛋白 2 (CRMP2) 中鉴定出一种短肽适体，称为 Ca2+ 通道结合域 3 (CBD3) 肽，可提供针对兴奋性毒性和创伤性脑损伤的保护。 ST2-104 是一种九精氨酸 (R9) 融合的 CBD3 肽，对神经性疼痛发挥有益作用，并且在阿尔茨海默病模型中具有神经保护作用；但ST2-104对脑缺血的影响及其作用机制尚未研究。在这项研究中，我们模拟了大脑中动脉闭塞（MCAO）大鼠的脑缺血再灌注损伤，并用谷氨酸激发 SH-SY5Y 神经母细胞瘤细胞诱导毒性，以探讨 ST2-104 对缺血/兴奋性毒性后自噬的影响侮辱。 ST2-104 减少了 MCAO 大鼠的梗塞体积并改善了神经系统评分。 ST2-104 通过减弱细胞凋亡和自噬以及限制过多的钙进入，保护 SH-SY5Y 细胞免于谷氨酸暴露后死亡。自噬抑制剂 3-甲基腺嘌呤 (3-MA) 可以促进 ST2-104 抑制谷氨酸引发的细胞凋亡的作用，而自噬激活剂雷帕霉素则不能发挥这种作用。 ST2-104 肽通过抑制 Ca2+/CaM 依赖性蛋白激酶激酶 β (CaMKKβ) 介导的自噬来逆转谷氨酸诱导的细胞凋亡，STO-609（CaMKKβ 的抑制剂）可部分增强自噬作用。 ST2-104 通过 CaMKKβ/AMPK/mTOR 通路抑制自噬，从而减弱神经元凋亡。我们的结果表明，ST2-104 的神经保护作用是由于通过 CaMKKβ/AMPK/mTOR 信号通路对细胞凋亡和自噬之间的串扰起作用。这些发现为 ST2-104 在脑缺血中的潜在神经保护作用提供了新的见解。