Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun, Jilin, 130021, People's Republic of China.
Department of Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Drive, P.O. Box 245050, Tucson, AZ, 85724, USA.
Mol Brain. 2021 Aug 6;14(1):123. doi: 10.1186/s13041-021-00836-0.
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 Ca 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 Ca/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.
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平衡方面起着关键作用，并且与脑缺血有着千丝万缕的联系。我们之前从钙调蛋白反应调节剂蛋白 2 (CRMP2)中鉴定出一种短肽适体，命名为钙通道结合域 3 (CBD3)肽，该肽可抵抗兴奋性毒性和创伤性脑损伤。ST2-104 是一种九聚精氨酸 (R9)融合的 CBD3 肽，对神经病理性疼痛有有益作用，并在阿尔茨海默病模型中具有神经保护作用；然而，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，我们通过大脑中动脉闭塞 (MCAO) 模型模拟脑缺血再灌注损伤，并用谷氨酸挑战 SH-SY5Y 神经母细胞瘤细胞，以诱导毒性来研究 ST2-104 对缺血/兴奋性损伤后自噬的影响。ST2-104 减少了 MCAO 大鼠的梗死体积并改善了神经评分。ST2-104 通过阻断凋亡和自噬以及限制过度钙内流来保护 SH-SY5Y 细胞免受谷氨酸暴露后的死亡。自噬抑制剂 3-甲基腺嘌呤 (3-MA) 促进了 ST2-104 抑制谷氨酸触发的凋亡作用，而自噬激活剂雷帕霉素则没有。ST2-104 通过抑制钙/钙调蛋白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凋亡，而 STO-609(一种 CaMKKβ 抑制剂)部分增强了这种作用。ST2-104 通过抑制 CaMKKβ/AMPK/mTOR 信号通路来抑制自噬从而减轻神经元凋亡。我们的结果表明，ST2-104 的神经保护作用是由于通过 CaMKKβ/AMPK/mTOR 信号通路抑制自噬来抑制凋亡和自噬之间的串扰。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。
